<p>While I could think about a low-cost alternative to AudioMoth <a href="https://www.pjrc.com/store/teensy32.html" rel="nofollow noreferrer">(Teensy 3.2 + audioboard)</a>, the global chip shortage applies to nearly all micro controllers.</p>
<p>A possible solution would be a <a href="https://www.pjrc.com/store/teensy41.html" rel="nofollow noreferrer">Teensy 4.1 + audioboard</a> that is somewhat lager and more powerful, but at the moment in production. I have the feeling that one could field 30+ systems in short time. The estimation of the overall power consumption would need a final configuration, especially in terms of sampling frequency.</p>
<p>Disclaimer: I'm a happy user of Teensy 3.2/4.1 and not affiliated with PJRC, the producer of the Teensy products.</p>
<p><strong>Edit</strong>:
The smallest (also very cost effective) system consists of</p>
<ul>
<li>Teensy 4.1</li>
<li><a href="https://www.adafruit.com/product/3421" rel="nofollow noreferrer">I2S Mems</a></li>
</ul>
<p>The largest component would be a battery pack that covers the 3 weeks.
The estimation of number of batteries will depend heavily on what your actual requirements are.</p>
<p>To give an idea: Assuming 50 mA consumption a 20000mAh powerbank could last for 300h or 12 days continuous recording. So, two powerbanks (with some protective diodes) may be necessary.</p>
<p>On Bit depth, the I2S Mems feature 24 bit ADC but only 18 or so are good. The Teensy Audioboard is properly good to 15-16 bits.</p>
<p><strong>Edit2</strong>:
I just tested a basic logger T4.1 + MEMS and got 85 mA current for continuous recording, so each 20Ah powerbank will last 7 days, so 3 powerbanks may be needed or different less powerful MCU. Unfortunately, such processors (like Audiomoths MCU that runs at 33 mA) are at the moment difficult to find, if at all.</p>
<ul>
<li>T4.1 about 40 mA (without uSD card, only Microphone to PC)</li>
<li>T4.1 about 75 mA (with uSD card connected, but NO logging)</li>
<li>T4.1 about 85 mA (with uSD card AND logging)</li>
</ul>
<p>Conditions: MCU clock: 24 MHz, sampling frequency: 44.1 kHz</p>
<p><strong>Edit3</strong>:
I was playing recently with some PAM implementations. They can be found under <a href="https://www.micropam.com/intro.html" rel="nofollow noreferrer">this website</a>. I implemented all three examples, 2 with Teensy 4.1 and one with a RP2040 MCU. While I assume that the standard PAM systems will soon be becoming again available, it should not be difficult to implement alternative systems.</p>

CC BY-SA 4.0
2023-02-16T21:17:02.430Z
Thanks for your response @WMXZ ! Since your comment, I've delved into the world of micro-controllers and have been seriously considering this option. Considering I want to measure different temporal/spectral variables on the chick calls, do you think bit-depth matters in considering a microphone? I couldn't find bit-depth specs on the Teensy microphone or similar ones.
Katrina W
CC BY-SA 4.0
2023-01-26T18:55:33.757Z
2023-04-07T17:51:33.543Z
2023-04-07T17:51:33.543Z
WMXZ
<p>I'm in the process of purchasing gear for this upcoming field season and am looking for audio recorder recommendations. I'm hoping to place ~30 small recorders in seabird rock crevices to record continuously for the hatch to fledge period (~3 weeks). I was hoping to get AudioMoth acoustic loggers but the global chip shortage has them out of stock until after my field season, and the SongMeter micro is out of my lab's price range.</p>
<p>Has anyone had any luck with cheaper, &quot;spy-ware&quot; type recorders in the field? I have heat-shrink wrap to waterproof them.</p>
<p>I'd also be interested in other audio loggers under/around $200, or renting them from another research team for Summer 2023.</p>
<p>Thanks everyone!</p>

<recording><pam><microphone><hardware><audiomoth>
What options are there for micro audio recorders?
# What options are there for micro audio recorders?

(Asked by: username_0 on 2023-01-24)

I'm in the process of purchasing gear for this upcoming field season and am looking for audio recorder recommendations. I'm hoping to place ~30 small recorders in seabird rock crevices to record continuously for the hatch to fledge period (~3 weeks). I was hoping to get AudioMoth acoustic loggers but the global chip shortage has them out of stock until after my field season, and the SongMeter micro is out of my lab's price range.

Has anyone had any luck with cheaper, "spy-ware" type recorders in the field? I have heat-shrink wrap to waterproof them.

I'd also be interested in other audio loggers under/around $200, or renting them from another research team for Summer 2023.

Thanks everyone!

**Tags:** recording, pam, microphone, hardware, audiomoth


---

## 1 answers

### Answer by username_1 on 2023-01-26. Score: 5 | Accepted answer

While I could think about a low-cost alternative to AudioMoth [(Teensy 3.2 + audioboard)](https://www.pjrc.com/store/teensy32.html), the global chip shortage applies to nearly all micro controllers.

A possible solution would be a [Teensy 4.1 + audioboard](https://www.pjrc.com/store/teensy41.html) that is somewhat lager and more powerful, but at the moment in production. I have the feeling that one could field 30+ systems in short time. The estimation of the overall power consumption would need a final configuration, especially in terms of sampling frequency.

Disclaimer: I'm a happy user of Teensy 3.2/4.1 and not affiliated with PJRC, the producer of the Teensy products.

**Edit**:
The smallest (also very cost effective) system consists of

* Teensy 4.1
* [I2S Mems](https://www.adafruit.com/product/3421)

The largest component would be a battery pack that covers the 3 weeks.
The estimation of number of batteries will depend heavily on what your actual requirements are.

To give an idea: Assuming 50 mA consumption a 20000mAh powerbank could last for 300h or 12 days continuous recording. So, two powerbanks (with some protective diodes) may be necessary.

On Bit depth, the I2S Mems feature 24 bit ADC but only 18 or so are good. The Teensy Audioboard is properly good to 15-16 bits.

**Edit2**:
I just tested a basic logger T4.1 + MEMS and got 85 mA current for continuous recording, so each 20Ah powerbank will last 7 days, so 3 powerbanks may be needed or different less powerful MCU. Unfortunately, such processors (like Audiomoths MCU that runs at 33 mA) are at the moment difficult to find, if at all.

* T4.1 about 40 mA (without uSD card, only Microphone to PC)
* T4.1 about 75 mA (with uSD card connected, but NO logging)
* T4.1 about 85 mA (with uSD card AND logging)

Conditions: MCU clock: 24 MHz, sampling frequency: 44.1 kHz

**Edit3**:
I was playing recently with some PAM implementations. They can be found under [this website](https://www.micropam.com/intro.html). I implemented all three examples, 2 with Teensy 4.1 and one with a RP2040 MCU. While I assume that the standard PAM systems will soon be becoming again available, it should not be difficult to implement alternative systems.

> **Comments:**
> **username_0**: Thanks for your response @username_1 ! Since your comment, I've delved into the world of micro-controllers and have been seriously considering this option. Considering I want to measure different temporal/spectral variables on the chick calls, do you think bit-depth matters in considering a microphone? I couldn't find bit-depth specs on the Teensy microphone or similar ones.  

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