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How can I remove permanent marker from a LEGO brick?
I need to remove permanent marker from hard plastic. How can I do it?

What color is the marker and the piece of plastic?  What type of plastic?  Most Lego pieces are ABS plastic, but I think the clear pieces are something else.

Unless the pieces are somewhat rare or expansive to replace, I suggest just getting new pieces as replacements. Chemicals that remove permanent markers will etch the LEGO pieces, and rubbing the marker away may leave scratches. It usually isn't worth the effort.

I use pure Eucalyptus oil. It works wonderfully. Keep in mind that if you are using it on LEGO, it will also remove the original printing (but won't harm the plastic itself), so I wouldn't recommend it in that case. But other than that Eucalyptus oil can remove marker, paint, glue-residue, and all kinds of gunk much better and faster than products like Goo-Gone. I'm an artist and use it on a regular basis. Eucalyptus oil is available in small bottles at health-food stores, larger bottles at pharmacies (that's what I use), and also at some Asian stores (usually the cheapest).

I've used a dry erase marker, over the permanent, to remove it from a white board.  I don't know if that'd work on Lego or not.

I know it's not the most cost-effective way, but I used to use gasoline on a rag to remove a lot of markings on plastics of all kinds.  It won't warp the plastic when used sparingly on a rag.
The only downside is that it may "smear" the marker, depending on the kind of marker that was used.

Rubbing alcohol has worked for me.

Using something you may already have in your home:
Aerosol hairspray
Spraying this over permanent marker allows the marker to be wiped off, and then you can rinse off the residue in warm water. I've used or seen used this remedy on many types of plastic in my life, but I can't recall if I've used it on LEGO pieces before. I think I did use it on a yellow brick some 12+ years ago, but time makes the details unclear.

Assuming it's regular alcohol based permanent markers, 70% Isopropyl alcohol will wipe it off easily. Coat a swab or wet a tissue, don't apply it directly to the brick - it slightly eats away at the material, but not to the degree where you'll shorten the lifespan of the plastic without repeated cleaning or prolonged exposure.

Dry erase marker works great but often just rubbing it out with a dry paper towel works also.

Without reading the existing answer from Grandpappy that also refers to Dry erase markers, I'm not sure what you mean?

Nail polish remover (or purer acetone if you happen to work in a lab) works really well. You can either soak the piece in it (I like to use a small tupperware container) if it is really covered, or wipe it away with a paper towel wetted with the solution.
This works because the sharpie in is a non-polar molecule and thus will dissolve in solvents like acetone. Rubbing alcohol also works like this, but is markedly less effective.

You need to be careful with Acetone though, as it will melt the ABS used to make the bricks if left for too long.

Using nail polish remover works really well. You can soak the piece in a small tub of it or wet a cotton ball down with the solution and rub the piece. The part that was rubbed will be a little rough, but scrubbing it with water for 30 seconds or so will remove it.

I would not recommend this, as nail polish remover is usually acetone which DISSOLVES the ABS plastic Lego pieces are made of. Not quite like the Wicked Witch effect, but it still damages the piece badly.


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What is the easiest way to sell Lego sets for a good price?
I have a HUGE collection of LEGO sets that I want to sell. Ebay is too cheap and Craigslist takes too long. Is there an easier and faster way to get some good money?

Similar: http://bricks.stackexchange.com/questions/1578/how-to-sell-massive-vintage-and-unsorted-lego-collection-with-manuals and http://bricks.stackexchange.com/questions/1160/how-should-i-go-about-selling-3k-worth-of-unsorted-lego-sets

@Kramii - I agree that this is very similar to How should I go about selling $3k's worth of unsorted LEGO, but I can't in good conscience close as a dup. with your excellent answer here ;) Perhaps if you were to include this in your answer there...

@Zhaph-BenDuguid: I took the other question to be about the nature of the LEGO (mostly unsorted sets), whereas this one is more about good places to sell. For this reason, I don't think they're quite the same question, even though they are related. If we need to discuss this further, I suggest we take it to meta.

Unfortunately, even with the best market conditions, there is always a trade off between selling things at a high price and selling things fast. That's just a principle of marketing.
That said, you might consider these options:
BrickLink / Brick Owl
These are sites that specialize in trading LEGO. I can't comment further, as I've only used these sites as a buyer, not as a seller. As a buyer, I've been impressed.
Both Bricklink and Brick Owl take a commission for each order that goes through.
Local Ads
Some people still rely on newspaper etc. adds for their purchases. Although they reach a smaller audience, they have three advantages over eBay:

Ads are generally a fixed price, so fees don't depend on selling price - ideal for large lots of LEGO.
If you sell locally, you don't have to charge postage, as buyers can generally collect.
It is arguable that people who mainly buy from local adds are generally less well informed about "realistic" prices than people who use web-based purchasing options, so may be willing to pay a little more (although this cuts both ways - they may under-estimate the true price of things, too).

eBay
Despite your aversion to eBay, it is still be your best bet, simply because you'll reach such a large market. Prices on eBay are driven by the market - by what people are willing to pay. For this reason, I'm not sure that it makes sense to say that it is "too cheap".
To get the best price for your LEGO, I suggest using the fixed price listing feature, setting the price at the lowest you're willing to accept. Of course, it may take a little longer to shift your collection if your prices are at the high end of what the market can tolerate. An excellent picture and a good description make a big difference, too, as can your willingness to ship overseas. If you do decide to ship internationally, don't make the mistake of underestimating postage costs.
I use eBay for all my LEGO sales, and I'm generally happy with the results. The only down-side is that the fees can be quite high, but I generally accept that for the convenience.

Is the set new in the box, and never opened? Is it retired and rare?  In that case, the skies the limit since the set may not be available anywhere.  When I find my self in this situation I generally list for the high-end price on brickpicker, but include a best offer option.
Do you have the manual, the box it came in and all of the parts and minifigures?  Then head on over to brickpicker.com and look up the trending used prices on the sets you want to sell.  Use this information to sell the item on ebay (but be ready to pay Ebay 15% of your sale price right off the bat!).  You can also try to sell locally, but you will have a hard time finding anyone willing to pay your asking price for what they will consider old used lego.
Is the set complete, but you have no box? See above, but adjust your asking price.
Are we talking about a collection from your childhood that is in a tub in your parents garage?  An unsorted lot?  A bunch of 'sets' of undetermined completeness?  Aim for $10 per pound, but accept $5 cause it sounds like you may be in a hurry.
-Brian

Can I suggest you also other ways like selling your sets on http://oldlego.com or promoting your selling on big Lego forums like http://eurobricks.com

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Why are Lego products so expensive in Europe?
Comparing a few Lego products at the official online store, I found U.S. prices seem to be consistently around 70% of those in Europe given current currency exchange rates. That's a surprising difference. Given that U.S. import tariffs apply to products manufactured in Europe (such as Lego), one would expect the price difference to be the other way around.
Edit: Found a relevant quote in a book written by Alex Stewart:

America is by far the cheapest country in the world for buying Lego;
  believe it or not sets are much more expensive in other countries.

What is the primary reason for this price differentiation? Better competition in the U.S.? Lower taxes? More wealthy Lego fans in Europe?

I'm going to guess that part of it is that the 19% sales tax is included in the EU but in the US sales taxes are normally applied only when you purchase (partly because they vary depending on your location). So a US purchaser might find state, county and city taxes applied.

That is correct. In addition consider the market; LEGO's number one and largest marketplace is the USA. They can afford to keep their prices low because they sell huge volumes. Also there is competition; LEGO is considered an expensive toy here as well, compared to other brands. If they would go any higher they would loose their customers.

Western Europe is LEGO's largest market, not the US. http://www.theglobalcmo.com/lego-global-marketing/

To answer this question, we must first check the accuracy of your observation that "U.S. prices seem to be consistently around 70% of those in Europe given current currency exchange rates."
Using data provided by Brickset, which pulls data from the online listings at shop.lego.com, we can compare the prices of sets released in 2014 that are listed with prices in both USD and EUR.
I downloaded this data and used a spreadsheet to analyze the prices. Using the 2013 average USD to EUR exchange rate of 1.3282465 I converted retail prices from EUR to USD. On average, the retail prices on the US site are 77.06% of the retail prices on the sites where prices are listed in EUR.
So your observation is close to the apparent actual difference in listed prices, although it is closer to 80% than 70% on average.
The member states of the EU each set a value-added tax (VAT) on items sold in those countries. This rate currently varies from 15% (Luxembourg) up to 27% (Hungary). LEGO includes the VAT in the listed price in countries where it is collected. This means the listed retail price is higher than the actual base price of the set. If you assume a VAT rate of 25% and adjust the list prices accordingly, then comparing the USD prices to the EUR prices shows that US list prices are actually about 96% of EUR prices. This is an average - many sets sell at a similar or lower actual base price in Europe than in the US (when expressed in USD).
For example Set 60045 Police Patrol sells for $44.99 USD in the US. It sells for 39.99 EUR in Germany. The VAT in Germany is 19% and today's exchange rate is 1.3398. To get the base price of the set in EUR, divide the list price by 1.19. That gives us a base price of 33.60 EUR. Multiply that by the current exchange rate and the USD price you would pay in Germany for this set is $45.02 - just three cents more.
Here is the data I use in a spreadsheet format, sorted by their prices in USD. The calculated columns on the right show the EUR prices converted to USD and the bases of EUR list prices assuming 25% VAT.

Thanks. I guess the fact that the base price without taxes is similar implies that LEGO slashes its profit margin in the U.S., to offset the effect of import tariffs. I found this article helpful too.

Perhaps, but LEGO has a factory in Mexico, which has a free trade agreement with the US and Canada. Also, labor costs in Mexico are much lower than in Western Europe.

Each state with a sales tax has its own law about whether sales tax has to be collected for online sales. For example, I live in a state that has a sales tax, but my state says that online retailers only have to collect the tax if they have some kind of physical presence in the state. There is no LEGO store in my state, so when I make a purchase at shop.lego.com, no sales tax is collected. On the other hand, there is an Apple store in my state, so online purchases from Apple are taxed. Some retailers, like Amazon, collect sales tax for all states, regardless of the local law.

So this shows how Lego prices in Europe roughly match US prices in the US, but sadly Canada gets screwed, with before-tax prices that are 20-30% higher than the US even factoring in the exchange rate.

Actually, Canada's base prices are very close to those in the US after you factor out the 5% VAT and using the current exchange rate of 1.09 CAD to USD. I have added more columns to the spreadsheet that show, on average, US base prices are 93% of Canada base prices (converted to USD).

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Cheap Lego sets for Kindergarten classroom?
I am wondering what is the best way to get a set of Lego bricks for my kindergarten classroom?  The children love playing with them and I no longer own them due to a transfer of grade levels.

Are you looking for Duplo or regular Lego?

If there is no need for the bricks to belong to specific sets (as in, it's not important to be able to build some official models from them) then I'd say the best way is to look for ebay bulk brick sales. For around 100$ you can get several pounds or around a thousand semi-random pieces. Try searching for "lego pieces".

If this answer was useful to you, please consider marking it as accepted. Thank you!

You have a lot of resources at hand as a teacher in your community.  Have you considered sending home a request for gently used LEGO Bricks in your student's folders at the start of the year?
The parents of your kids may not have any on hand, but will certainly know someone who does!
-Brian

You may also consider renting them from Pley. Their website allows for set rentals at a discounted rate. I'm sure if you emailed them they might have something special for educational institutes as well. I heard they are running a school program.


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Identify minifigure torso - yellow with blue "N" on front
I've got a yellow torso (with yellow arms). The front (I believe) has a large blue letter 'N' with a orange drop shadow. Otherwise the torso is plain.
I've tried loads of search terms on bricklink to no avail, but sometimes the description on bricklink is bit hard to predict...

i think you mean this part
Yellow Torso Nesquik Bunny Large 'N' Pattern / Yellow Arms / Brown Hands

from  4051-1": Nesquick Rabbit
or
4049-1:Nesquick Rabbit Film Set

I Still can't figure out how to search for the string 'N' (search term includes single quotes) in bricklink

The BrickLink search bar is quite dated and doesn't work too well. In the case of this particular torso what I would have done is to go to the Catalog Tab, than right under it click the Colors Tab, then scroll down to Yellow, click on the first number (which is the number of parts in that color). Then click on Minifig Torso, and sort the results by Thumbnail Gallery. There are only 52 minifig torsos ever made in yellow, so it is really easy to scroll through them. In most cases searching by color like this is a great option.

Didn't know you could search by color that way!. Always frustrated me that the torso description usually doesn't contain the main color. Thx

Is it possibly from Quicky the Nesquik Bunny figure?


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Help to identify a unique minifig head
I have a minifig head that I can't find on the Brickset website or else where. Not sure where it came from but found it amongst a pile of odd bricks my kids had collected years ago.

The head is probably from before 2002 (last time any of them played Lego). I thought maybe from the Legend of Chima range, but couldn't find it in the sets or minifigs and don't have any other models from that range.
I don't have a figure that might match it but I'm just intrigued to know what it is.

It's one of the Indians from the Western theme, from 1997:
http://brickset.com/minifigs/ww016/Indian-Tan-Shirt-Quiver

Great, thanks @Huw Millington for the quick id!

@ken then why not accept the answer


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What is this model number please?
I don't have the instructions for this and I have no idea what model number this is.
Can anyone identify it?

It appears to be a partially-constructed 8242-1 Slammer Turbo

I even think that part of the launcher is visible at the top of the picture


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Are NXT Light sensors compatible with EV3?
I would like to use the NXT light sensors with my EV3 brick. I don't have enough light sensors as I need 2 for each robot (per set) and it only comes with one. However, I have a lot of NXT sensors. Will the EV3 be able to use the NXT light snesor and is the NXT light sensor as accurate as the EV3 light sensor?

possible duplicate of Will Mindstorms EV3 be backwards compatible?

The question asks "is it as accurate as the EV3 light sensor?" The EV3 has a Color sensor.  There are important differences, like the ability to turn on/off the 3 color lights.  I'm not editing because the main question is about the Light sensor.

NXT Color Sensors are supported directly by EV3-G, the EV3 software running on the PC or MAC.
NXT Light Sensors are not.
To use Light sensors requires a bit of trickery.  EV3-G has a Raw Sensor block that provides access to the Light sensor values.  The raw sensor returns values from 0-1023, which is very different than the 0-100 of the NXT-G Light Sensor block.
Setting up the Light sensor to use ambient or reflected light is also solved with a bit of trickery.  Use the Sound Sensor Block and toggle the dB setting.
Once that much is tested and working, create a set of MyBlocks to mimic existing Color Sensor blocks.

Raw sensor value works, but shows a level of dark, not of light :), meaning that higher values indicate lower light.
Ambient light works directly, but for reflected light you need to insert a EV3 Color Sensor block with Reflected Light mode to turn on the light in the NXT Sensor. After that, use raw values or the Sound sensor block.
The Sound sensor block is not included in the download version of the EV3 software (at least not in mine), you can download the necessary ev3b file from http://www.lego.com/en-us/mindstorms/downloads and then import it into your project.

The kids on the FLL team I coach created a video that explains how to use the NXT light sensors on an EV3. Hope it helps. http://youtu.be/I7Bqvk-uMLk?list=UU2r9xq9o39SbEX1cESNdIHA

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Preparations for outside display
I am thinking of using LEGO to make some outside yard art, (large minifig scale castle) and wondered what I should do to prepare them for being outside in variable weather conditions (in the Seattle area).
I am aware that Legoland glues their displays, but have not found any other details on their technique.
Discoloring in the sun is not a big concern of mine, other than I will probably avoid too many white elements which tend to discolor more noticeably.
As it's ABS plastic I imagine water wouldn't be a problem, and I should just be able to wash them down if they get dirty.  What about snow/ice freezing temperatures?
Does anyone have any experience with outdoor displays?

Check out another post here: http://bricks.stackexchange.com/questions/1037/what-glue-should-i-use-for-permanent-lego-construction/1038#1038  that asks a specific question about glue.

I once talked with a Lego Builder at the Florida park. He told me they use a glue that actually melts the Lego blocks together. With that in mind, I searched and found this article (on Facebook). It says Lego Park Model Makers

use a solvent based plastic weld. It heats the bricks up so the edges bind together. Obviously it has to be very strong to withstand weather conditions.

A quick search on that found this from Google shopping.
The article also talks about color fading and model life time (about 5 to 7 years), after which the model can either be rebuilt or cleaned:

We clean them using a shot blasting technique. They are sprayed with a fine salt spray, which takes a very thin layer off the bricks, and then they are lacquered with a UV coating. This gives them another 3 years or so.

I hope the project goes well.

good link, I've seen more info on how the LEGO parks glue their models, here but this one mentioned they spray models with a clear UV coating, and gave some outside display lifetime estimates (5-7 years) also mentions salt water shot blast refurbishment method.  Thanks


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I need information on LEGO part #3001 in Milky White with Sparkles
Have a 3001 part i have come across with a color i've never seen before. It seems to be a milky white but with glitter in it. New style logo with pip on short side.
Any ideas to where it came from?

If you have any additional information about where you came across this part, any pictures, etc. that you can include in your question (rather than in the comments to an answer), that might help others supply more information.

According to a comment from Jan.k 1974 on the source you mentioned (in your comment to 62Bricks answer):

The milky white brick dates to 2005 and has been been made exclusively for the Allianz Arena (Munich soccer stadium) model in Legoland Günzburg. I remember they sold spares of these in packs of 5 for 1.99 after the grand opening

This is confirmed by Maxx3001 in reply (emphasis added):

[…] that's the left brick with slight sparkle in it.

At the time of posting, ND Toys was listing these at $2.39 on BrickLink under "Milky White" with the description:

MILKY WHITE 2X4 BRICK WITH SPARKLES (from LL park spare parts)

The arena, and the milky white bricks can be seen in this shot on the LEGOLAND website:

You may have what is commonly called a "test brick." Many of these were manufactured by the Bayer company in Germany. LEGO had Bayer test various designs and colors for their evaluation before deciding whether to put them into regular production.
One recognized authority on these bricks is the collector Maxx3001, who documents his extensive collection on Flickr. In his comment on this trans-red glitter test brick, he makes reference to the existence of milky white glitter bricks. He may be able to give you more information on your brick.

Maxx is the user i got the part from. He has little info on the part. He has a pic of the part to the left here https://www.flickr.com/photos/maxx361/5494084763/

Bayer also stamps letters on the test bricks not the LEGO logo like i have mention above.

Some test bricks do have the LEGO logo on them.

It may or may not be a test brick is not an answer. I ask for some detailed info and you just gave speculation and a source that has already gave all the info he knows. From the source we have so far this is NOT a test brick. Im sorry to get kinda rude but i want to get to the facts, speculation has been done for a while now. I would like to hear from someone who knows about this part.

And asking for details on a piece for which you have not posted an image, and not indicating where you got it and what you already know about it is not a sincere question. Sorry to be rude, but if you are not going to provide complete information, you're going to get speculation.


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Does anyone have a picture of the Lego Club alphabet code from Bricks and Pieces magazine?
Somwtime maybe in the early eighties, I read a Bricks and Pieces magazine with a small panel showing the brick alphabet code and it would be great to have a picture of this if someone has it.
This code used an apparently random brick construction for each letter of the alphabet, and it would be fun to write messages into MOCs using the code, or to see if anyone else has already done it.

Not to mention that naming pieces with these letters and referencing to this question would raise a couple eyebrows... Maybe you're on to the best way to I.D. basic parts without a paragraph description per!

The code was introduced as a puzzle in the spring 1981 issue and is explained in the summer 1981 issue. (Page 7 at the bottom of the page).
the issue can be found found at: http://www.1000steine.com/brickset/miscellaneous/BricksAndPieces/1981-2%20Summer.pdf
And here is the code:

Enjoy!

Nice, but I'm sure that it was two pieces each letter, using a slope and a 1x1 brick.  I'll look through the rest of the archive just in case there is something else that fits.

Thinking it through, it would have been sometime around the Futuron era, late eighties.  I've checked on bricklink and the sets look right for what I remember from the magazine promotions.


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Where can I buy engraved LEGO bricks?
What is the cheapest site to buy engraved LEGO bricks?
I am searching for the cheapest site to buy engraved 2X4/2x6 bricks so that I can put names on them and send them to people. Any insight is greatly appreciated.

Online I would recommend BrickEngraver
I think your best bet would be to find a local trophy shop, most will engrave items.  Take them some LEGO to test and they should be able to provide what you need without the need to pay shipping.

+1 I think BrickEngraver was the company we used when we did the Brick Fiesta convention, and they turned out really nice.


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EV3 bluetooth controller for mac
Is there a suitable EV3 controller for mac? It should be a compatible alternative from the official EV3 controller in the iOS app store or google play.

You could try the MonoBrick Communication Library.  It is supported for Mac OS and does use Bluetooth as a way of communicating with the EV3 brick.
MonoBrick was listed by IntroRobotics with three other software development resources for EV3.


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How to build an automatic Lego train system?
I was wondering if anybody has ever tried using the IRLink NXT sensor to make an automated train system and if so, what kind of setup did you have to make it all work?
I have been working on a train station for a while now and would like to create an automated system that will stop the train inside the train station for a set amount of time (maybe 30 seconds). As of now, I had an idea to use the touch and IRLink NXT sensors to make the system work. When a train approaches the station it will somehow hit the touch sensor. Then the IRLink sensor will send a signal to the IR receiver stopping the train inside the station. Then after 30 seconds, the IRLink sensor will send another signal to the IR receiver which starts the train. This will be continuous as the train track setup, as of now, is in a loop connecting both ends of the train station. I would also apply the same system on the opposing tracks in the station.
Am I overlooking anything that might make this not work? Are there any better alternatives to the touch sensor? Does anybody have any ideas as to how to avoid a collision within the train station if two trains are approaching less than 30 seconds apart? And finally, are there any experienced NXT programmers that could give me some advice on the programming aspect of the system?
I like this system because the train does not need any positioning awareness on the track for it to stop within the station every time.

Related: http://bricks.stackexchange.com/questions/1798/simplest-approach-for-rail-sets-automation

Easier said than done guys ... I’ve been trying it for a year now. Arduino and Lego esp. with PF system are extremely complex and require advanced programming skills as well as expertise in coding.

I think I'd use the ultrasound sensor instead of the touch sensor (or the brightness sensor with the light turned on in a dark tunnel). I haven't tried this but I'd worry about the touch sensor derailing or scratching the train. Otherwse, your system sounds pretty doable. The collision risk could be addressed by setting up the sensor a little further before the station and sending a stop signal to the second train if it triggers the sensor while the first train is still at the station.

And if the train runs over a minifigure it would get stuck, so perhaps the train could be programmed to stop attempting to turn it's wheels if it detects a sudden drop in rotation speed.

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What set does this minifigure head come from?
I came across this picture:

I think the body is from The LEGO Movie Pajamas Emmet polybag, but have no idea where the head is from.

more comment, it's the face on
twn203: Queasy Man (10244)

It's from Fairground Mixer (10244).
Also, the rest can be had way cheaper than Pyjamas Emmet polybag in the form of Sleepyhead from Collectible Minifig series 6.


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Is there a time mechanism that can be added to an NXT program?
I wanted to create a system where an NXT block would be set into function at a certain time of day (maybe 5:00 and then 5:10 and so on). I would want the timing function to be embedded into the NXT program. Is this a possible function? I have looked for documentation on the web but have not found anything useful..

To get the actual time of day, you can use the mindsensors.com Realtime Clock Sensor.

Time is thought of as a sensor value, measured in seconds. The Timer sensor can be used directly, as part of a Wait For block, as part of a Loop block.

Is there a numerical limit to the sensor block? It seems 86,400 seconds between each function is quite a long time.

86400 seconds is a long time for an NXT.  I think mine shuts down after ten minutes of inactivity.  If it can be set to never shut down, how long do the batteries last?


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How to make NXT bricks communicate information?
Is it possible to connect, in some way, two NXT bricks that has program functions running on both. For example, Brick one would tell brick two that it is okay to start a program. Are there any sensors that could facilitate this type of communication?

You can use the Bluetooth mailbox feature to pass messages back and forth between 2 NXTs.
If you want to use sensors, you could use the HiTechnic NXT IRLink Sensor (NIL1046) and NXT IRReceiver Sensor (NIR1032).


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How much does the NXT brick weigh?
I am working on a project that involves LEGO Mindstorms bricks but for some tasks I want to know the weight of the NXT brick, so I would be pleased if anyone can help me.

Without batteries installed, the NXT brick weighs 159.3 grams, so that's about 0.351 pounds.
Do take into account the added weight of what ever batteries you have installed, though, as that will almost double the weight, and not all types of AA batteries weigh the same. If you're using a rechargeable battery, then for reference, the original NXT rechargeable battery weighs 155 grams (~0.341 pounds), and the newer rechargeable battery weighs 136 grams (~0.2998 pounds).
The weight of a single AA battery according to www.allaboutbatteries.com are:
Alkaline: 24g
Carbon-Zinc: 19g
NiCad: 29g
NiMH: 26g
Lithium Ion: 25g


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I bought a second hand pack of pieces and it looks like it may be a specific set
Hoping for help to identify a set of lego pieces. It definitely has a car wheel base, and the base boards are green.close

A lot, but definitely not all, is likely from Race 3000.

That's great thanks so much... Definitely the race 3000 pieces, just putti together.... Still have a heap of pieces and cars... Not sure if this is a set or to....


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How can I use 1 motor for grabbing/lifting and another for moving?
I am really stuck on how to use the three motors for better functions. Is there anyway in which I can use 1 motor for efficient/quick movement while turning left and right?
Another thing is whether I could use a single motor for turning objects 180 degrees on one side and lifting objects on the other end of the robot, is that possible? alternatively, is it possible to lift and grab using a single motor?
Lastly, would it be less efficient to use two NXT bricks to increase motors capacity?

If you simply need more motors(or sensors), check out this other question: http://bricks.stackexchange.com/questions/3027/how-to-use-two-nxt-bricks-for-3-motors-and-4-sensors/3030#3030

There are also some suggestions for this sort of thing on this question: http://bricks.stackexchange.com/q/646/56

Do these functions (grabbing/lifting/moving) need to be run simultaneously or can they be run in order?

Typical solutions involve staggering functions, so at the limit of one motions travel the other motion starts. For example, combine lifting with gripping by making the lift happen when the grip stalls (many older crane grabs work this way)

Is there anyway in which I can use 1 motor for efficient/quick movement while turning left and right?

Yes, if you use one motor to drive a wheel and another to steer the vehicle. Using an NXT motor for steering would be quite wasteful however, you should at least use gearing to convert the jittery, fast movement of the NXT motor into slower, more balanced steering. You could also look into using Power Functions parts, the servo motor being the obvious choice for steering applications.

Another thing is whether I could use a single motor for turning objects 180 degrees on one side and lifting objects on the other end of the robot, is that possible?

If these two need to operate separately, then you will need to sacrifice some functionality. It is possible to split a motor's output into two axles in a configuration that drives only one axle depending on the direction of the motor. See this setup: How can I make a precise one-way clutch using Technic elements?
This will only allow either axle to turn in one direction only, so if you need lifting AND putting back, you'll need to solve it as a circular function. Driven by the only input axle that is turning in one direction, the lift would need to raise and lower back to the original position without any other input.

alternatively, is it possible to lift and grab using a single motor?

Using some clever mechanics, it is certainly possible. The 8868 Air Tech Claw Rig/Materials Handler used something like this to automatically grab an object, raise its arm, open the claws, drop the arms and start the cycle again. All this using a single motor (and some pneumatics). In this way though you won't get any control over the details (how high it lifts, etc) or over the sequence itself (you can't grab and release something without lifting it).

Lastly, would it be less efficient to use two NXT bricks to increase motors capacity?

You could certainly use two NXTs and have control over 6 motors. This would however require more batteries, result in a larger and heavier model and necessitate some kind of synchronisation between the NXTs. All of these drawbacks can be mitigated, so if you can't seem to solve the problem using engineering (or have proven that it is impossible to achieve your goals using only 3 motors) then feel free to throw in another NXT.
If you need to increase the number of available motors, you could look into using third party parts, like this motor multiplexer that allows you to use two motors on one sensor port.

If this answer was useful to you, please consider marking it as accepted. Thank you!


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Decals for LEGO Pharaoh's Quest Flying Mummy
Do all LEGO sets have decals?  I am specifically looking for decals for LEGO Pharaoh's Quest Flying Mummy.

I don't have any, but there are at least 67 of them available on Bricklink: http://www.bricklink.com/catalogItem.asp?P=7307stk01
(and no, not all sets have stickers)

authors: 醫家有藥-全港最大醫生處方藥平台


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LEGO mindstorm - which product to use to make projects mentioned below
I'm planning to buy a Lego Mindstorms kit for the following projects. I haven't really used Lego before - my friend asked me to consult him about projects (I use microcontrollers and build robots from material I find in my garage).

Two track tank with a distance sensor to create a map of a room. A gyroscope sensor to measure the angle of slope would also be very useful. It would use fuzzy-logic, A* algorithm and OpenCV if I decide to put a web camera on top of the tank.
Inverted pendulum (PID controller). It needs an encoder and a rather high speed motor which can change it's direction of rotation.
Some crawler (like a snake or spider) - models with holonomic constraints.

Now I'm considering the EV3 basic educational kit and I think it doesn't fit my needs. I also can't understand some things about software - if I buy a kit for home use, I suppose I shouldn't buy any software.
Questions

Which kit would be the best fit? Maybe two kits or even three?
Is the servo limited in rotation or can it be used as a simple electric motor? If no, then which motor can be?
Can I program the models using free software (downloaded from a website)? C or Java is preferable. NXC is nice too (it looks like C, but I haven't used it before).
How to remote control the robots? Should I buy additional Wi-Fi adapters?

A basic EV3 seems to be enough for most of the basic projects, but you might find yourself in need of a handful of extra parts (gears, beams, etc). The basic kit does not include a gyroscope, but you can buy an extra one separately. The same stands for the ultrasonic distance sensor.
The alternative is the educational set which already includes the ultrasonic sensor.
All EV3 sets come with the official software, but for any serious project you should indeed look for a more capable software. For Java there is LeJOS, for C there is NXC. Both are free and open source.
The motors sold in EV3 kits are capable of continuous rotation, but also have position encoders in them, making them capable of moving with 1° precision. For more precision you can always use gearing or other mechanics to reduce movement.
Remote controlling is possible with Bluetooth (built in) or with WiFi (via an external USB dongle).

Thank you very much. I've checked there is a gyro sensor in ev3 education core set.

If my answer was useful to you, please consider marking it as accepted. Thank you!

@IvanIvanov Just to add, LeJOS provides a remote control utility for controlling motors and reading sensors wirelessly. You can link to an EV3 over bluetooth or Wifi, but you will need to buy a wifi adapter for EV3. NXC is for the NXT brick, not the EV3 - if you're looking to code C, take a look at EV3RT.


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Direct command lego ev3
Is there any documentation about direct command bluetooth of EV3?
Thanks,
regards!

What do mean by direct command? Do you want to, using code running on the EV3, communicate directly to the EV3 bluetooth module?

There are bluetooth commands to drive the motors directly, without the help of ev3 use a program, but there is no documentation about them. I get some commands from source codes of any libraries, I can control motors ev3 by set velocity and power, but I can't control this by step or degrees

Try http://ev3.fantastic.computer/doxygen/index.html and http://ev3.fantastic.computer/doxygen-all/
It seems to be the best option at the moment.


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Can anyone identify this spinner with 1-5 and a skull?

My son has just inherited a large box of Lego, we're hoping someone can help identify what set this might be from.

It's the center of set 2519 Skeleton Bowling:


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Is the LEGO Mindstorms EV3 brick waterproof?
I am trying to build a ROV (Remotely operated underwater vehicle) with LEGO Mindstorms Ev3. Is it waterproof?

No, the LEGO Mindstorms EV3 is NOT waterproof. Any electronic product that is capable of being immersed in water will clearly state in the packaging/manual the level of water protection provided. This may be in the form of an IP Code:

Ingress Protection Marking, classifies and rates the degree of
  protection provided against the intrusion (including body parts such
  as hands and fingers), dust, accidental contact, and water by
  mechanical casings and electrical enclosures.

Source: http://en.wikipedia.org/wiki/IP_Code
However, it is possible to contain the EV3 brick within a waterproof case, there are already many cases available suited to Smartphones, Tablets, Cameras and other Digital devices.

If your remotely operated underwater vehicle requires some form of propulsion (perhaps from a propeller powered by a EV3 motor) then you may required to make some alterations to the case. Any physical alteration will compromise the waterproofing and safety of the protective case. Do so at your own risk.

If you intend on building a NXT submarine, check out these projects: https://www.youtube.com/watch?v=gYT3hTpNT4E and http://hackaday.com/2012/08/14/lego-rov-without-a-tether/


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Is it possible to connect EV3 and NXT bricks like master/slave configuration via bluetooth?
Can I make a Bluetooth connection between LEGO EV3 bricks and LEGO NXT bricks? and If it is possible how to handle the software to make  a chain between them?

There are many possible ways of doing this. I am a contributor to the ev3dev project, so I am a bit biased in that direction.
To do this with ev3dev, I would install the nxt-python package on the EV3 and use it to remote control the NXT.
If you want to stick with the standard firmware, another possibility would be to relay bluetooth mailbox messages through a PC or other device. Here is an example (it goes in the other direction though - NXT controlling EV3).
Another possibility is to use Lejos or MonoBrick. Both have NXT and EV3 remote control libraries,

I use C++ instead of Python on ev3dev. How do I use bluetooth there?

How about this? http://www.yakachu.de/nxt/

umm, I actually cross-compile and execute C++ right on the device, in ev3dev. it provides TTY for various motors but bluetooth isn't one of them. the link you posted is something completely different


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What part can I use to get the connection
This is what I have..

Would like to connect the long "thing" to the square base.. not sure which part will give me a angled elevation
In case you are wondering what I am trying to do.. this is what I am trying for the same exact purpose
http://www.youtube.com/watch?v=4PcL6-mjRNk

You are going to have to explain a little better than that.  If all you are looking to do is connect two neighboring pieces, you can use something like http://www.bricklink.com/catalogItem.asp?P=43857 or http://www.bricklink.com/catalogItem.asp?P=32140

Hey, Nick tks for responding back.
if u look at the youtube video I want the long thing to be elevated but also connected to the square base... something like TitanFall (video game) orbital shooting cannon..kind of setup.. I think the youtube video pretty much sums it up...

This may call for a bit of re-designing. I don't think there's a special piece for angled elevation, because you can mimic the effect with a gear.
Use a 24- or 40-toothed gear, and attach your "arm" to it. This has the advantage that you can connect it to a servo or motor using a few more gears - I assume you want to mimic the ball-throwing device in the Youtube clip.
You can connect the gear to your base in a number of ways, although personally I'd build the base from "normal" technic beams (e.g. the 16x1 types), If you insist on using your current base, you'll have to add a construction that you can put the axle through.

Yep, and if you use a worm gear you'll have a built in locking mechanism.


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Lego Motor for cycling a tool
I am curios to know if I can utilise the Lego Power range to rotate a transducer to a set point and return to its original position and if so is it able to cycle the movements repetitively? Ideally I would like to set the motor to run  to between say 0 degrees around to 240 degrees and then back to 0, 100 times although these figures could change.
Any advice/help is greatly appreciated!
Thanks

It would be difficult to get the exact rotations that you are talking about using Power Functions parts. The servo motor would be your best option, but its range is fixed to +/- 90 degrees from center. If you use a controller with variable speed, it will rotate through 7 steps to get to 90 degrees in either direction.
If you're willing to look at Mindstorms, there is a servo motor with a built-in rotation sensor that was released with both NXT and EV3. These can both be rotated to and from any position, and they are accurate within 1 degree. It sounds like that's the best option to meet your needs.

If you don't need constant speed motion a better idea would be to use a crank running from any modern motor (ie, geared down internally). That way you can guarantee the end points. For a 240° rotation you might need to gear up after the crank, but as long as there's a spring or constant load in one direction backlash shouldn't be an issue.

Here;s a really quick sketch of what I mean. Your motor drives the black axle in the foreground, and that rotates a full 360° (continuously). That pushes the cyan lever backwards and forwards, rotating the black gear. Which in turn drives the grey gear which is your output. By judicious fiddling with the gear ratio and the crank lengths you'll be able to get just about any output rotation you want.


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Need help to identify minifigure
Can someone help me to identify minifigure linked below:
I´ve been searching now about three hours without luck :)

Knight's Kingdom II - the guardian (picture taken from bricklink)
http://www.bricklink.com/catalogItem.asp?M=cas264
I searched on Bricklink catalog under, 'minifig leg assembly' using the keyword, 'brown,' using thumbnails.  Only had two pages to look through.


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Why are some of the supports on bottom of a lego piece hollow, and other are solid?
I've added an image of me holding two 1x3 bricks, one has solid supports (not sure the technical name...) and the other has hollow supports.
Does anyone know the reason why they are different? Other than that, they are identical and from what I know they were purchased at the same time (I didn't buy them).

Almost assuredly it is a move to reduce the amount of plastic used. It may seem inconsequential, but adding up hundreds of millions of these makes for a ton of savings. The same thing goes for the brick walls, but not in the case of the ones you show here. I haven't seen it in any 1x bricks, but in most 2x bricks these days, the walls are a tiny bit thinner (perhaps the cause of many complaints of translucency) but with little ridges there the studs touch to keep clutch at appropriate levels. One might guess that this new wall would reduce the number of times a brick will accept a stud before losing reasonable clutch power.

I'll buy that as an explanation, thanks for the answer.


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How do I get the Mindstorm EV3 software to recognize an NXT brick via Bluetooth?
I'm trying to program my NXT brick via the EV3 software over a Bluetooth connection.
I can connect it via USB (although that too failed initially, but has since been resolved; not sure why) but I'd really like to do it via Bluetooth as I could with the NXT 2.1 software.
How do I get the EV3 software to recognize my NXT brick over Bluetooth?
Here is a copy of the connection area in the EV3 software showing that the NXT brick is available via USB but not Bluetooth:

And here is the same NXT brick available in the NXT 2.1 software:

A screenshot of the lower right corner of the EV3 software running on your PC/Mac would help.  There is a collapsible panel there that should list EV3/NXT(s) connected.  Also, the NXT has to be ON.

Update: it now connects via the USB cord but not via Bluetooth even though I can connect on the same machine with the old NXT software.  I'll include a screenshot when I get a chance.

Could you get a chance? Or have you been able to solve the problem by yourself? If so, please share with us what you learned.

Update: It will now recognize via USB but not via Bluetooth.  I'm not sure what changed.  I've updated the question to target Bluetooth only.

Communicating with the NXT from the LEGO MINDSTORMS EV3 software is not supported.
From http://www.lego.com/en-us/mindstorms/support/faq/:

3.10 Is the LEGO® MINDSTORMS® EV3 Home Edition Software backward-compatible with NXT Hardware?
Yes. You can program your NXT Intelligent Brick using the new LEGO MINDSTORMS EV3 Home Edition Software. However, not all Software features are supported by the NXT Intelligent Brick.

It does not explicitly mention Bluetooth, but it is one of features that is not supported.
References:

Compatibility EV3 software with NXT brick - known limits?
http://robotsquare.com/2013/07/16/ev3-nxt-compatibility/

That's unfortunate.  It looks like Lego is no longer supporting the NXT software on Yosemite so Mac users will no longer have Bluetooth as an option for NXT.

Does Lego no longer support NXT 2.0 at all? I am running Mac OS X 10.15 (Catalina) and the EV3 software can't detect my NXT 2.0 using USB.

LEGO officially stopped supporting NXT in 2015, however the original NXT programming software is still available on the official LEGO MINDSTORMS web page. The original NXT programming software and EV3 desktop programming software are both 32-bit, so cannot run on macOS 10.15. The new EV3 programming software based on Scratch does not work with NXT. So the only way to program NXT on macOS 10.15 is with 3rd party software such as NXC/NQC or leJOS.


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Substitutions for vintage hinges
I've recently gotten back into LEGO and I'm trying to restore old space sets (late 80's era) by buying parts on Bricklink. I've noticed that some of the hinge pieces are extremely expensive (e.g. parts 4275 and 4276), often making a single hinge assembly cost over 5$ if using "new" parts.
It seems that Lego has discontinued these parts some time ago, so I was wondering the following:

Why were the parts discontinued? Were they prone to breaking?
Which newer parts can be used to substitute these and are they really better? I don't mind if they don't look exactly the same as long as there is functional equivalence.
I'm assuming that there is no substitutions possible for the old canopy hinges (e.g. part  4315)?

What I remembered of those parts was that force was needed to snap them together, and I believe I also have some that are broken over the years.
The part was introduced in 1983, updated in 1985 and the last sets were released in 2002 with one set in 2004.
In 2003 the parts are replaced by Hinge Plate 1 x 2 Locking with Dual Finger on End Vertical' (44302) and Hinge Plate 1 x 2 Locking with Single Finger on End Vertical' (44301). These parts have a number of fix angles in which the hinge can be placed. This finger shape is also added to al kind of other parts, like the canopy
There is also a version for non fixed angles Plate, Modified 1 x 2 with Clip Horizontal on End and Plate, Modified 1 x 2 with Handle on End - Closed Ends and these can also be combined with other parts

Joost answered eloquently, but I'd like to add that while 44302 and 44301 were made to replace the finger hinge they won't work in all situations. The geometry of 4275 and 4276 allowed useful techniques - you could use it to reverse studs by 180 degrees in a small amount of space, 90 degrees, and more. The new pieces can't do the same, which is a shame.
(Side note: the finger hinge are my favourite pieces ever. I even got them tattooed on my arm :)


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How can I tell if my NXT motor is faulty?
I pulled my old Mindstorms NXT out of storage (it's been there for a few years). After patching together a test robot, I noticed that my motors behave strangely.
At first, one of the motors did not respond to move commands. After disconnecting/connecting a few cables, another motor stopped working (with a different cable, on a different port). While troubleshooting, the behaviour erraticaly switched between all three motors working (rarely and for a brief time), two not working, or one not working.
Now it's stable, with one of the motors not working, always the same one, no matter what port I plug it in. I suspect that it may be faulty, however I'm not sure due to the strange behaviour described above.
Does anybody know how I can test the motors, see which are faulty, if any? Or any other tips troubleshooting this? Thanks.

If the one motor exhibits the same behaviour on any port with any cable and the other motors are working on all of the ports with any cable, then it is safe to say that the problem is definitely with the motor itself.
Make sure you swap cables as well as motors to rule out a faulty cable.
Also, check for signs of corrosion on the pins of the cables, motors and NXT. This kind of erratic behaviour is indicative of poor electrical connections.


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Vision Command and Exploration Mars software for Mindstorms RIS 2.0
I recently bought a set 3804 LEGO Mindstorms RIS (Robotics Invention System) v2.0 very well maintained but did not have the installation CD of the RCX program and IR tower. With some research on the Net, I managed to find the RIS v2.0 software and the expansions Extreme Creatures and RoboSports.
This set also includes the USB Camera from the Vision Command expansion but without the installation CD and the problem is that I can not find the software nowhere. Where can I download the software in English for the 9731 Vision Command and 9736 Exploration Mars??
I found a similar question here which was answered by another user with the links for the download of the software Vision Command but one was in German the other in French.

As it just so happens, I'm physically in possession of an English Vision Command CD. I've uploaded the iso here:
https://www.mediafire.com/?xo6xfjvnbzaaf7u
I didn't upload and post it in that other question you mentioned since I wasn't aware none of the Vision Command ones were English, but I've also updated the answer in that other question with this link for completeness.
Note that this software was originally designed for Windows 98. The very first thing you should do is run the install file in compatibility mode for Windows 98, otherwise you'll get an error telling you that your version of Windows is too new. And if you keep getting warning messages saying that this software has known compatibility issues, click "Continue anyway" for every one of them. I'm also wanting to say that you sometimes get an error when the camera itself is installing. In this event, just keep clicking "ignore" or "retry" or whatever until it finishes. I've been able to get the software to install and run on Windows XP, Vista, and 7, although the camera won't be recognized by your computer if your operating system is 64-bit. I'd be interested in seeing if that driver David Lencher linked you to would fix this problem for 64-bit operating systems.

Thank you. I have searched for this software since I bought the RIS v2.0 set. Now I'm happy :)

I managed to obtain also the expansion 9736 Exploration Mars but I lost my installation CD and as the expansion 9731, I can not find the software to download on the Internet. Can you also help me on this?

I'm afraid that RIS 2.0 and Vision Command are the only RCX-era software I physically possess, so I can be of no more help than anyone else. Sorry.

Hello again. I managed to obtain the installation CD of 9736 Exploration Mars. I shared on the "Multi Software Download" -> http://bricks.stackexchange.com/questions/4414/where-can-i-download-the-software-for-old-rcx-era-mindstorms-sets

I found this page: http://riskonomics.blogspot.com/2009/06/lego-vision-command-camera-drivers.html
The author says that he was able to get the camera to work with a Logitech Webcam driver is730enu.exe (which is linked on that page).
From the sound of it, the original driver wouldn't do you any good anyway unless you are still running Windows XP.

Would make sense as under the hood LEGO seemed to use the Logitec cameras for both LEGO Studios and Vision Command.


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Convert 3rd party NXT programming language code to NXT-G program?
Is there a way to convert code from one or more 3rd party programming languages used for programming the NXT into a program that can be loaded up in NXT-G? If not, do any text-based languages provide support for making custom blocks that can be imported into NXT-G?

possible duplicate of Is there any other way to program the Lego Mindstorms NXT other than the provided software?

I disagree. This question is about converting source files from other programming languages into a format readable by NXT-G, not asking what programs exist as an alternative to it.

No, there is no automated way to convert source files from other programming languages into un-compiled NXT-G code. The .rbt format is very complex, so writing a program to interpret programs written in other languages and generate a proper .rbt file with properly placed and configured blocks would be an incredibly time-consuming and tedious task that wouldn't be worth the effort. You'd be better off manually translating each program manually.
As for your second question, it is possible to make custom blocks for NXT-G, although not in any text-based languages. Custom blocks are made in LabView, a graphical programming language that has a wide variety of uses, including programming NXT robots. See this tutorial on creating custom NXT-G blocks if you're interested:
ftp://ftp.ni.com/evaluation/mindstorms/NXT_Creating_MINDSTORMS_Blocks.pdf


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Resources to learn useful common Mindstorms mechanical construction patterns
I'm currently working on building a small scale CNC-like (X-Z, no Y axis) machine to cut glass mosaic tiles.
I decided to give it a go using my EV3 set and I'm having some trouble with the Z-axis movement.
I find I'm loosing too much time figuring out by myself how to build what I'd expect are known elementary construction units, or what I'd call "patterns" (get my SW Eng bg? :-)). For example: a circular-to-linear movement using the medium servo (push vs pull), commonly used gear assemblies, duplexing servo movement axis, etc.
I'm looking for resources where to learn some basic construction patterns that would help me speed up building more complex structures.  For example, a while ago I saw a book that seemed to contain some construction patterns -> combining gears, how to build strong structures, ... I can't find it anymore.
Any available online/offline resource that could help is welcome.

I've had trouble finding good examples as well. One of the most interesting one is, sadly, in Spanish, but the images (and some help from Google Translate) helped me some. Hopefully it can be a start.
http://www.hispalug.com/foro/index.php?topic=11730.0

sadly it covers mostly constructions using 'studded' (pieces) while EV3 uses studless beams.

Ah - didn't know that, so thanks for saying that :) I'm mostly a system builder myself. This is supposedly the largest technic blog as far as I know:
http://www.technicbricks.com/
Maybe you'll have better luck there?

There are two sites I can think of that describe commonly used gear assemblies. Both sites make use of animations to illustrate how the gears work.
LEGO Education: Constructopedia
This web article produced by The LEGO Group introduces common, basic usages of gears and pulleys. It includes alterations to the direction of gears, idler gears, gearing up/down and pulleys at angles.
TECHNICOPEDIA: Building Fundapementals
Technicopedia: Building Fundapemtnals describe more advanced usages of gears and different gear types such as bevel, worm, rack and differential gears.


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Teleoperated arm trouble
I have built a robotic arm with the lego Mindstorms ev3.  My goal is to control its motion via teleoperation, that is , to have a gyro sensor strapped onto my arm and have the robot mimick the up and down motion of my forearm.  However, I am completely stumped concerning the programming.  I need a reliable way to read the gyro sensor readings while taking into account any bias in the sensor.  Second, I would also like the sensor to read the rate of change in my arm and translate that into power for the large motor.  If anyone can show me how to do this with the ev3 programming environment, the help would be greatly appreciated.

Are the robotic arm (motor) and the gyro sensor connected to the same EV3 brick? If two EV3 bricks, the programming is more about the communication protocol between the bricks.

Yes, the gyro and the motor are on the same brick.  I am considering getting another ev3 brick, as I could easily see how to program that setup.

Disclaimer: I have never used the EV3 interface, only the text based programming languages for the NXT. Therefore I might be proven wrong.

I need a reliable way to read the gyro sensor readings

I think the gyro sensor should have come with the appropriate instructions to do that. If not, you can find many tutorials online, such as this: http://robotsquare.com/2014/06/25/tutorial-gyro-ultrasonic-sensor-ev3-home-edition/

while taking into account any bias in the sensor.

Bias can be accounted for by using a previously known position to calibrate the sensor. You could start your program with the gyro (and your arm) in one of the extreme positions and measure movement relative to that.

Second, I would also like the sensor to read the rate of change in my arm and translate that into power for the large motor.

This sounds like a simple differentiation task. You measure the angle and store it along with the current time (in milliseconds or whatever the most precise measurements available). In the next iteration you make another measurement, take the difference of the current and the previous angles, and divide it by the difference of the current and previous times. The result is the rate of change. This can be translated to motor speeds by using either trial and error, or calculations based on the characteristics of the motor, the gearing and the gyro.
However, I would rather use a command to turn the motor a specified number of degrees to match the measurements of the gyro.


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Why I get this message saying "unable to compile some documents for deployment ev3"?
I have a LEGO Mindstorms EV3 program that I was working on for a long time but recently and suddenly when I try to download the program the software displays the following message:

"unable to compile some documents for deployment"

Taking into consideration that there are no missing blocks and the sensors ports are adjusted correctly and checked many times. What is the main cause of this and how can this be fixed?

that happend to me to but i tried everything but nothing works for all you people out there try deleting the lego mindstorms it self then redownloading it

Is that the whole error message or are there more lines to it?
You could always try copying and pasting your project pieces into a new project, maybe the project file itself got corrupted in some way.
It also might be possible that some of your custom blocks have errors in them.
If none of these work for you, then try to isolate the source of the error - hold Ctrl and click on parts of the program, then press Run Selected (looks like play sign with parentheses) to check if the error is still there. If the error goes away after testing a specific block, then it is the source of the error, therefore you should look more closely to find the issue.

If You are using Custom "My-blocks", try copying their content, deleting the block, then pasting it into another tab and re-make it. Hope I helped :)

Create a new MyBlock and delete the old MyBlock.
So, you have to create a new MyBlock with a different name and move all the programming to the new MyBlock. Then delete the old MyBlock and replace the old MyBlock with the new MyBlock. This did work for us.


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How can I use the EV3 educational firmware instead of the retail version?
I have an EV3 brick from the retail kit, which is currently running the retail firmware. I would like to replace the EV3's firmware with the educational version. How can I do this?

Update: LEGO Education software is now available for free.
https://education.lego.com/en-us/downloads/mindstorms-ev3
Original answer:
You need to purchase the EV3 Education version of the software. It includes the EV3 Education version firmware.

EV3 Education Software (single user licence)
EV3 Software v1.1 Update (includes v1.06E firmware update)


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Faulty NXT Motor
I have a motor that prevents the program from running. It simply allows a few slow movements forward with stops in between. It seems very stiff to rotate manually. Any way I can repair this motor?

This happened to me a long time ago. I ended up just getting a new one to replace it. I'm wanting to say that disassembling a motor beyond a certain point makes it impossible to reassemble, so I'm not sure how practical it would be to repair a motor.

I agree with HaydenStudios, it is impossible to disassemble completely NXT motor without breaking the orange axle hub. You can nonetheless half-open it enough to see what's happening inside (you need a Torx screwdriver - T10 size if I remember well - to open it. See photos here http://philohome.com/nxtmotor/nxtmotor.htm.
Anyway, first try to see what LEGO support can do for you!

I had a similar problem with the RCX about a month ago.  Check the wires for shorts or fraying, and if you can open the case and look for shorts in there.  I fixed my fraying wire with electrical tape.

Glad to hear you could fix your problem with electrical tape. I doubt that will help this "Faulty NXT Motor", since "very stiff to rotate manually" is an indication of broken gears inside to motor.

Mine was also "stiff to rotate" until I fixed it


text:
Brick-built alternative to "Door 2 x 5 x 5 Swivel, Bracket Base"
I am trying to make a brick-built alternative to the swivelling door piece that's frequently used to provide secret entrances in castle sets.
Example: this combination (images from Bricklink)

The pre-fab Lego piece has several advantages but is also fairly ugly for use in builds that don't rely on panels for walls. Its main advantage though is that it is compact and swivels around the centre, which is possible because the inner piece is very thin and slightly narrower than the outer piece.
I have achieved a similar pattern using the 2x2 turntable tile but getting the turntable positioned under the wall so that the wall spins on its centre means I need to use two levels of jumpers, both at the top and bottom of the wall. This consumes a lot of vertical space and also juts out horizontally at the top (Why doesn't Lego have an inverse jumper? one stud-hole on the bottom, two studs on top?)
Here are pictures of my creation. I'd appreciate any tips on how to make it more compact.
Note that the round 1x1 bricks are needed on the sides to make enough room for it to swivel. It still rubs a bit but it's fine.

The first layer of jumpers offsets the turntable so that the wall spins on its central axis. The second set of jumpers allows the wall  to be centered over the turntable. On top, I have to hang the jumpers out, then repeat with the turntable and then more jumpers. In this prototype the dark grey layers are jumpers and the black layers are turntables.

Why not use just two jumper plates (3794), one on the top and one on the bottom? No more additional are pieces required.

You can also replace the stack of 1x1 round bricks with a single Support 1 x 1 x 6 Solid Pillar (43888) piece. The piece is used in conjunction with a large swinging vault door in the Bank & Money Transfer (3661) set. The brick is stronger then a stack of 1x1 round bricks and the round part of the brick (at five bricks high) is tall enough for most minifigures.

I considered the single jumper approach but thought it would be too ... I'm not sure. Too tight to turn? Too easily knocked out of its frame?

If you plan to build more of the wall on each side and maybe above you will add strength to the frame. It actually isn't as difficult as I expected to turn the wall but the turntable is certainly easier to turn.

I like the idea of using the pillar piece. I have a bunch of those, I just wonder if I'll have the right colours. Otherwise, I would probably have stuck a 6L bar in side the 1x1 round bricks.

I built a prototype of this type of swivel door and in my prototype I find that the door no longer smoothly fits between the round bricks; it rubs too much and bends the round bricks outward.I can't figure out why, though.

That's very strange. I can't think why that is when both your wall and mine are 1x6.

I tried mixing your solution and mine: using my 2x4 turntable solution at the bottom and a single jumper at the top. It turns in between as easily as our respective solutions. Somehow, adding the turntable seems to decrease the friction of the edge of the door on the round 1x1s. I've tried several times and none of them turn as freely (and with as little friction on the frame) as my original solution. Am I imagining it? I can't figure it out.

You could try something like this if you have Technic beams available:

This solution looks nice but your prototype is only 1 plate shorter than mine. It does look like it should be possible to make it shorter though. And I like that it's the door that's rounded instead of the wall; in some circumstances that will be a huge structural advantage.

It should be possible to make this a little shorter. One simple way would be to build a full size Technic brick into the floor rather than the half size one that I used. This would allow you to flip the pin at the bottom the other way around and allow the platform that the minifig is standing on to be lowered down to the level of the ground. That assumes that you have space to build into your floor, though.

I played around with this solution and found a couple of issues. For one, I don't have enough technic beams to make this work, but that's not a flaw in the solution itself. The bigger flaw is that the ledge where the minifig stands can only stick out by one stud or else the door can't swing all the way open. I need at least 1.5 studs to fit a fig or else they lean awkwardly. (My use case is that the fig is a statue, not a character). Also due to my lack of technic pieces I can't build it well AND have a platform. It'd still be a great solution for a swivel wall with no platform though.

If you need more space on the platform, you could use 7 wide beams for the door rather than 5. While being bigger than your original design, this should give you plenty of space for your statue.

What part of this isn't doable with standard LEGO pieces?

If you're asking why I used Technic parts, it's because they provide a very compact, sturdy, and nearly frictionless way to create a pivot point at the top and bottom of the door. They are also rounded on the ends, which prevents the door from binding.

Ok, not quite what was asked, but this might spark some new directions for other people.

As to your statue, a few 2x1 plates at the base instead of the tiles could attach to the legs.
This solution would allow weapons, etc, to be displayed on the secret walls.
Re-edited to include final improvements.

Using tiles and inverted tiles lets the wall be two plates thick, which allows movement without looking ugly, this build is surprisingly sturdy.  All in grey this would look much like a castle wall.

This works and offers some interesting possibilities for the outward facing side, on account of the snot construction. But the back side of it doesn't look as nice and is rather clearly a door. Maybe that could be disguised better, by using a 2x4 plate with two pin holes underneath instead of just one, and then extending technic tubes up to the top, and building the same structure (but non functional) on the other side. considers

I tried this construction. It's promising, but ultimately doesn't work for me. When I build it your way, with the hinge set on a jumper, I don't see an easy way to attach it at the top of the door and that makes the door too flimsy. When I use a 2x2 tile with a pin on it, this moves the door half a stud forward and then it rubs too hard against the frame and can't really be opened.

Fair enough, the, 'back of the door,' problem could be solved with inverse tiles (http://www.bricklink.com/catalogItem.asp?P=11203), the attachment at the top of the door could be a half-peg onto one of those rods underneath the 1x? plates, but the stiffness is still a problem, maybe some more SNOT with some L-panels (http://www.bricklink.com/catalogItem.asp?P=4865). mounted on a sideways 1x? plate.

I worked out that an upside-down plate would function as a bottom hinge, this design is still not perfect.


text:
Train track switching using servo motor
My project requires using a servo motor for switching track. It needs to be automate switching points. Is this possible? What is the cheapest / easiest way of achieving this?


text:
Is it possible to use a LEGO NXT ultrasonic sensor for a LEGO train crossing?
I was looking at LEGO NXT components, and I found the ultrasonic sensor. I was wondering that if I put off to the side of the track, the nose of my train would activate the sensor, thus operating the servo and closing the gate?... I have already prepared my crossing with a gate attached to a 12 stud axle. At the end of the axle pointing away from the track, a servo would  move the axle at about 45 degrees. Is this possible or are there any alternatives that would work better? I'm not sure if my idea has been attempted before with Power Functions tracks. Also note that I am using a 32x32 base plate. I am hoping that I won't have to use a Mindstorms control panel (I'm not entirely sure what they're called) because they are so expensive.

As you suspected, you cannot use the Ultrasonic sensor without an "Intelligent Brick" (EV3 or NXT). MINDSTROMS would be a great way to automate your train if you are willing to make the investment.
For more ideas on how to use LEGO MINDSTORMS with LEGO trains, check out Sioux.NET.

Thank you! I appreciate my question being answered and you have contributed to my LEGO City layout!


text:
Help identify this 70s or 80s lego space set
I bought some bags of LEGO bricks which appear to contain a 1970's space set in it. I want to find instructions to put it all back together.

The brick with the space logo is from either set 452/894 or set 6901.  The buggy is technic set 1972.  Information from Bricklink search.


text:
Help identify mystery piece and set it could go to
More mystery parts from the bags of LEGO pieces we bought.  I can't find a LEGO symbol on it.  Is it a LEGO part or some other brand?

I have never encountered this piece before, but what I do when I find pieces that I cannot identify, I first look at the studs. Obviously yours does not have any studs, so what I would do is either check inside the element, or look it up online. If more than one source says it is, then case closed. If you cannot identify it even after searching, you should talk to a brick specialist. That's all I can tell you. Hope this helps.

This would be a Crane Bucket - Complete Assembly (Top, Jaws, Spring).
It could have come from any of 29 sets from 1974 to 2012.

gev has the exact name of the piece, but I'd like to add one more point that could be helpful. When trying to identify pieces as Lego or non-Lego, pay attention to the more obscure standard connections. The small ball above the hinge is a standard small ball joint connection, recently revitalized by the Mixels series (among other things). It connects to the old Lego figure arms, as well as trailer hitches and the like. It's about the only thing on the piece that's standard Lego, but it is a defining feature.

It could've been from the 2012 city mine set. It was used to build the crane.

Here's all the sets this part was in:
http://rebrickable.com/parts/3492c01/crane-bucket-complete-assembly-top+-jaws+-spring/14


text:
9v and Power Functions Hybrid?
I am building a train layout and I am running some of my track through a tunnel. I would like to know if I could hook up a 9v train motor at the opposite end of my train. The front will use Power Functions for the motor. Will this work together in case my IR receiver loses communication to the controller and at the same time run at the same exact speed? Is there an alternative?

I'm not so sure using 9V will be usefull ?
My son has a PF cargo train in his room, when he turns it on, it goes, ok.
but even if my son goes downstair to get a cookie while he still has the PF emitter in his hand, then train still runs !
According to me, PF infrared link is used only when you wish to change speed setting, so if you don't plan to slow down your train in the tunnel, you are ok.

One option is to only use the 9V train motor, but power it most of the time with the PF battery back.  This will require some customization of the motor, and probably some cutting/soldering of the wires, but this would work. (See: Can 10153 9V train motor be powered by the Power Functions Battery pack?)
Another solution is to add a second battery pack in parallel to the first, and only turn it one when the train is in the tunnel.  You can mechanically (and automatically) turn it one when the train enters the tunnel, and then turn it off when the train leaves the tunnel.  A small switch under the train (using something like two of these to make a switch that can be "flicked" on and off).

If you don't connect the two subsystems electrically, then it is quite possible to do so. The Power Functions motor will be on when it can get a signal and the 9V train motor will be on when the train runs over the metal rails. The metal rails will need to have external power attached, and you have to adjust the speed there separately. The mechanical resistance of the unpowered motor will probably have undesired effects though.
If you can't make a seamless transition from unpowered rails to powered ones, then you might look into building a more complicated setup where a PF remore receiver "sets" some kind of mechanical variable that controls the on-board motor output. This way even if you lose PF reception, the train will still run at the speed you set last.
If your train is longer than the tunnel, you could also install two PF receviers, one in the front and another in the rear. This way one of them will always be in range.
You could also consider using an SBrick. It controls PF units via Bluetooth, so no line-of-sight is required.


text:
where can I find simple Lego ideas
I have just acquired a bunch of bricks and specialized bricks. Where could I get a lot of ideas?
Anything to do with a city would be good. I have already tried the LEGO club.

just found out about lego ideas book expensive

You might consider checking out the LEGO Adventure Book. There are two volumes available now, and they are full of interesting ideas (I wrote a review on the first one here: http://thebrickblogger.com/2012/12/lego-book-review-the-lego-adventure-book/.) They are not only City related, but many of them are. Also, if you like LEGO's own designs, you can download instruction books on LEGO's website and use those for inspiration. They are available here: http://service.lego.com/en-us/buildinginstructions/.

That's a pretty vague question, but here are some general resources on city building:
Rebrickable has a large selection of MOCs. Browse through it and see if you can find something fun there.
You can look through all of the official City sets. Brickset is a good place for that.
Twinlug has a fun Micropolis standard you can use to build a large layout together with other fans.
When you get serious, you might want to get into the modular buildings - it has become a pretty common standard to build for as well.
Hopefully that gives you a start.


text:
NXT shuts down USB on Mac after connecting motors
After successfully connecting our NXT to my Macbook Air and upgrading firmware to 1.31 we built our first robot. We plugged in the motors to ports A, B & C and now we get an Error stating that USB ports have been shut down because a device is drawing too much power. I have tried Reseting NXT and now it is stuck in "clicking mode" I have tried two different computers and three different cables. I also plugged in in through a USB hub all with the same result. I have restarted, Shutdown and restarted, Unplugged and restarted, Reset P-Ram.

The clicking mode means that you need to reload the firmware on the NXT (under the Tools menu in the NXT software).
If you still get the overcurrent shutdown using different cables and different computers, then the conclusion has to be that there is something wrong with the NXT itself. The USB port should be drawing little to no current at all since the NXT has its own power source.
It would also be worth contacting LEGO support if you do indeed have a defective NXT.

I get the over current shutdown using different computers and cables. I will contact Lego. Thanks


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Mindstorms crashes when connecting to EV3 with Bluetooth
I am using OS X 10.10 (Yosemite) on a 2011 MacBook Air, LEGO Mindstorms EV3 Home Edition v1.0 and the latest firmware on the EV3 (v1.06H)
When I attempt to pair the EV3 with my Mac over Bluetooth, then Mindstorms consistently crashes.
Here's what I do:

Connect the EV3 with the USB cable
Select "Refresh" in Mindstorms
OS X prompts me to pair the EV3
I click "Pair"
Beachball appears for a couple of seconds, and Mindstorms crashes.

Any hints on what to do?

There appears to be a known issue with the Bluetooth stack in Yosemite. Until this is resolved, you won't be able to pair the EV3 with a Mac.

It works now, with the latest version (1.1.1) of Mindstorms.

Sweet, glad it's sorted :)

This might help to the problems:
If you download the latest version of mindstorms by the Mindstorms-Site you´ll get the version 1.1.1.then you can connect via Bluetooth to the brick with the newest version EV3 (v1.o6H)
But if you are like me a teacher and using the educational version of Mindstorms (version 1.1.0 (note the last zero)), then you will have serious problems to connect your brick using Bluetooth in OS Yosemite!

Try pairing it while the LEGO MINDSTORMS EV3 software is closed using Bluetooth in System Settings. Then open the LEGO MINDSTORMS EV3 software and try to connect.

Sorry, but Pairing the EV3-Brick isn´t possible, because it isn´t listed in the Bluetooth-objects.

Pairing it while the LEGO MINDSTORMS EV3 software is closed is the way to do it. Using Bluetooth in System Settings to connect the laptop to the robot first, then open the LEGO MINDSTORMS EV3 software and establish the connection with the robot.
You need to update education software to 1.1.1.
Get the patch from:
https://education.lego.com/en-us/educationdownloads/download?assetid=14d8bec7-9de6-4d9b-ab8f-891993ecf501&ignorereferer=true


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Strain Gauge on LEGO Bridge
I had an idea to teach my son (almost 4) about bridges and large structures from an engineering point of view. I thought that it would be cool to build a large bridge and put a strain gauge on it. One of those foil like strain gauges. Then I would drive some heavy LEGO cars filled w/ pennies over it and we could watch the resistance change on the strain gauge.
My question is, would it be possible to get some meaningful results out of this? I see a number of problems.
1) I've never used a strain gauge before, and I'm wondering if the pulling apart of the bridge due to the various forces is an appropriate use case for a real strain gauge. The deformations would get rather large quickly since we're working with bricks and could possibly render the strain gauge useless.
2) The introduction of the strain gauge itself, glued onto bricks radically would change the way that the forces are distributed. The strain gauge now acts as a physical support holding two bricks together.

Why not use a pressure sensitive adhesive such as Blu-tack instead of glue? That way you can still re-use your bricks and strain gauge.

Lego bricks can withstand a fairly high pressure before they deform, but Lego creations tend to deform more easily at the various connection points. Therefore it's possible to build a relatively easily deformed bridge using long pieces, such as technic beams. You could build a bridge that deforms easily and then show how it flexes under the various weights.
As for using a real strain gauge, that might be overkill, but if your bridge is fairly bendy you could probably compensate for whatever structural rigidity you'll get from the guage itself. Also I'd go with putting the gauge on a separate, flexible piece (such as paper or plastic) and just pin it to the bridge using normal lego parts. Presumably you don't need super-accurate measurements for this demo?
Lego also has some springs and shock absorbers which can possibly be used to help with your design. Either use them to make the bridge flexible, or use the compression of the shock absorber as your measurement of how deformed the bridge is.

A pure mechanical strain gauge seems more in the spirit of Lego. And more likely to work and be robust. I suspect you could make a simple "spring balance" type gauge quite easily using a rack piece and an 8T gear, with either rubber bands or suspension print parts. Add a cardboard circle as backing and "calibration" just consists of adding weights and marking points on the dial.

I have designed some special measuring tooling for my previous employer that uses strain gauges, but is is not always that easy. You need for sure:

an amplifier,
glue them on the construction in the correct orientation
2 strain gauges on both sides for temperture compesation
a way to calibrate the measuring device or construction

this resulted for us that we most of the time we were using commercial available tooling like load cells and only make our own if commercial was not an option.
I don't know what will happen if you glue them over the joint between 2 brick, but the measurement will not correct. These strain gauges have a liniear behavior when glued to a surface. When we had a strain gauge that was not correctly glued or got loose we noticed that in the measurents.
I thing I was wondering about, for who are you planning to do these measurement, your 4 year old son, or for your self. I think if its for your son, that he is to young to fully understand this, for the effort you need to get it working.
If its for your son, I would just let the brigde break, when the load is to high. If you want to visualize  the behavior you can also use 1 of the bridge construction games that are available for example on Steam. These show with colors the stresses in the different beams.

I know that he's young, however even if he misses the point, it'll still be worth it since it's something we'll do together. He thinks that "inflation" is a bad guy we need to put in jail :).


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How make robot turning going straight?
I have been struggling with this function for a while.
I want my robot to turn left until it detects black then turn right until it hits black again. Then, I will divide the angle in half and call rotateTo to make the robot move that angle. I don't know why it is not working the way I want it to.
The reason I do that is because after I turn left or right it is not exactly 90 degrees. That is why I want to make sure it is facing the right direction before it continues moving. Here is the code:
int numberTurn = 0;
int numLeft = 0;
int numRight = 0;
RegulatedMotor Left = Motor.A;
RegulatedMotor Right = Motor.C;
while(color_id!=7){
    moveForward(300, 50);
    color_id = color_test.getColorID();
}
while(color_id==7){
    moveForward(300, 50);
    color_id = color_test.getColorID();
}
color_id = color_test.getColorID();
Left.resetTachoCount();
Right.resetTachoCount();
while(color_id!=7){
    Left.rotate(100,true);
    Right.rotate(-100,true);
    color_id = color_test.getColorID();
}
Right.stop(true);
Left.stop(true);
numLeft += Left.getTachoCount();
while(color_id==7){
    Left.rotate(-100,true);
    Right.rotate(100,true);
    color_id = color_test.getColorID();
}
Right.stop(true);
Left.stop(true);
numRight += Left.getTachoCount();
while(color_id!=7){
    Left.rotate(-100,true);
    Right.rotate(100,true);
    color_id = color_test.getColorID();
}
Right.stop(true);
Left.stop(true);
numRight += Left.getTachoCount();
numberTurn = (numRight-numLeft)/2;
Left.rotateTo(-numberTurn,true);
Right.rotateTo(numberTurn,true);
while(Left.isMoving()){
}

Left and Right is motor. For color_id, 7 is black
Anyone have any ideas why it doesn't work?

The main problems I see are the following:

The value in the numRight variable is wrong for two reason: The 'right' sensor is not reseted at the proper time and you read the 'left' sensor value instead of the 'right'.
The angle calculation is faulty
The half rotation is performed in the wrong direction

Here are my code comments:
//Move forward until you find black
[...]

//Move forward until you are not on black anymore
[...]

//Reset the rotation sensors
[...]
//   WARNING: The right sensor is reset for no reason
Right.resetTachoCount();

//Turn left until you find black
[...]

//Get the left rotation sensor data
[...]

//Turn right until you are not on black anymore
[...]

//Get the right rotation sensor data
//   ERROR: This action should not be done until you have turned all the way to the right
//   ERROR: At this stage the right sensor should be reseted
//   Note: ...and the 'left' data was put in the 'right' variable
numRight += Left.getTachoCount();

//Turn right until you find black
[...]

//Get the right rotation sensor data
//   ERROR: This data should come from right.getTachoCount();
numRight += Left.getTachoCount();

//Calculate the half angle
//   ERROR: The calculation should be: numberTurn = ((numRight + numLeft) / 2 ) / 2;
//   Explaination: By adding the two rotations and then dividing by 2 you get the average of the two.
//                 The result is then divided by 2 again to get the half angle.
numberTurn = (numRight-numLeft)/2;
//Rotate back (should be to the left) to half the angle
//   ERROR: Rotation is performed to the right when it shoud be to the left
Left.rotateTo(-numberTurn,true);
Right.rotateTo(numberTurn,true);

Recommendation: When dealing with multi steps processes like this one, add the steps one by one while re-testing each time. The test should validate that the previous steps are still working and  that the added step is working as planned.

@Phav, is this helping?  I can refine the answer if it is not clear.

Your answer is clear. I just notice that from your answer. Thank.

authors: Жамол Усмонов


text:
What are the largest LEGO® Power train sets available commercially [Oct 2014]
What set(s) are the largest by number of pieces? These sets could be retired or existing.
I am also curious what set(s) have the most rails pieces included.

Right now, the largest commercially available train is the Lego City Cargo Train, Set 60052. It comes in at about 887 pieces. There are 30 rail pieces in this kit. Extra rail pieces are also commercially available through Lego. The 7898-1 cargo train would come in second as far as piece count. Same amount of track as the 60052.

Apart from those mentioned by Joe, there are several larger sets in the Advanced Models category. They are not powered out of the box, but can be motorized.
These are:

10233-1: Horizon Express 1351 pieces
10219: Maersk Train 1237 pcs
10194: Emerald Night 1085 pcs
10183: Hobby Trains 1080 pcs (This is actually for the previous train system, that used electrically conductive rails on 9V - so it is simultaneously powered and incompatible with the new, all-plastic rails)

Also, if you need more rails, check out the dedicated rail packages:

8867-1: Flexible Train Tracks
7499-1: Flexible and Straight Tracks
7896-1: Straight and Curved Rails


text:
Can I pitch an idea to LEGO?
How would I contact LEGO about an idea for some kits to be built and sold?
I have designs for simple kits that I have built for my son that I think would be very popular.

LEGO doesn't directly take product ideas from fans.
However, there is a website called LEGO Ideas where you can post creations that may potentially get turned into official LEGO kits.
The process is as follows:

Submit your idea to LEGO Ideas.  Take some time to get good pictures, and write a good description, or your idea will probably not make it off the ground.
Get votes for your idea.  The way LEGO Ideas works is that ideas that can get 10,000 supporters (votes) in a year will get put into a review process.  The best way to get votes is to share your idea.  Tell your friends, and spread it on Facebook or other social media.
Go through the review process.  Once you reach 10,000 supporters, your idea goes to the LEGO review board.  The review board will look at your idea, and decide if it is worth creating as an official set.  Things like size, cost, part complexity, new parts, and licensing will all be factored in to the review.  Be away that only about 1 in 10 ideas that reach the review board are approved by the review board.
Buy your new LEGO product.  Once the review board green-lights your idea, it will be turned into an official LEGO product!  The products are often, but not always, limited edition kits, so get them while they last - as the creator you are given complimentary 5 sets and 1% of net sales.

Hopefully, this will give you some background on the LEGO Ideas process if you want to pursue that route to get your idea turned into an official LEGO kit.


text:
Is the LEGO Midstorms EV3 software compatible with OS X Yosemite?
OS X Yosemite (10.10) was just released yesterday. I want to upgrade, but I am worried that the EV3 software will be incompatible.
What should I do?
A. Upgrade
B. Stay on OS X Mavericks (10.9)

The educational software of mindstorms is not yet updated.(Version 1.1.0)
If you download the free version of mindstorms (Version 1.1.1) you can connect via Bluetooth under Yosemite to your brick!

Thanks a lot! I had to resort to the cable because the bluetooth wasn't working. I'm so happy the the update fixed it!

B. Stay with OS X Mavericks.  I can confirm that bluetooth no longer works with Yosemite. Spent two hours trying to make it work, but in vain.

The new update v1.1.1 for the programming software fixes the issue. See below.

I have run the LEGO MINDSTORMS EV3 software successfully on Yosemite Beta for a couple weeks. The only problem I have had is that I cannot get Bluetooth to work. The bluetooth problem appears to be at the OS level rather than a software compatibility issue though.
Update:
I reported this to Apple via https://bugreport.apple.com. It was marked as a duplicate, so apparently Apple knows about it. Unfortunately, their bug reporting system is not very open and you can only see your own bugs. There is no other feed back on the status of getting it resolved.
I would suggest that everyone that has the problem report the bug as well. This should let Apple know there is demand to get this fixed and hopefully they will make it a priority.

Same here. Upgraded my MBAir (late 2013) to Yosemite and now can't connect over bluetooth to the brick (EV3) anymore...

Same, my EV3 bluetooth no longer works with Yosemite :-(


text:
What are the curve radii for the curved slope pieces?
Does anyone have a table with the curve radii for the curved slope pieces?
If not, does anyone have a good idea for measuring a third point on the curve?
Since I know the front and the back "coordinates" of the curve piece, I need a third point to get the radius. I was thinking about making some sort of jig, but I don't have any good ideas.

On reddit, user Pegajace used AutoCAD and LDraw models to produce the following results:

From the album https://i.stack.imgur.com/LOAeL.jpg
Probably, the ones with 100.0 LDU and 170.00 LDU radii are correct, however the other ones that don't report an integral number of LDUs are probably slightly off.
I remember a presentation from a Lego Designer Michael 'Mike' Psiaki (who worked among others on the roller-coaster and Saturn V sets) at the LEGO Portugal fan weekend 2018 where the radii were presented in a table and only one curved slope had a non-integral radius.
Unfortunately taking pictures of the presentation was discouraged.

These curves have been approximated by the contributors to the LDraw project. You can download free software to view and use the part files, from which you can approximate other points on the curve. For example, here is an LDraw part file shown in "wire-frame" mode:

LDraw parts are drawn in increments of the "LDraw Unit" (LDU) in which a standard 1x1 brick is 20 LDU wide by 24 LDU high (not including the top stud). By examining the part in an LDraw viewer, I was able to establish the coordinates of some of the points on the curve: