How to make a conveyor belt with LEGO parts? I am making a small robot with an Arduino and Technic LEGO powered by stepper motors. I am planning on moving small rocks throughout my machine. Does anyone have an idea of what kind of Technic LEGO parts I can buy to make a variable length conveyor belt? I have a lot of gears so it's the underlay that's my problem. Does some kind of elastic LEGO parts exist that I can use for this? Chain-like or rubber or hard plastic. IT Would be best if I could make it as long connected as I want.

Maximum size of the small rocks is about the same size as an 1x1 LEGO brick, so the conveyor does not need to have a width of more than 2 cm.
You will need to decide between 3711 Technic Chain Link and 3873 Technic Chain Tread, or possibly use them together.

Each link of chain is about 1 cm long and 0.8 cm wide

 and you can get them in packs of 108 (Chain Link Set Product Code: 2000645)

 

The Chain Tread are wider, 

but seem to be available only in smaller packs, such as
Set # 9938-1: Conveyor Belt Links (Nominally 36 links)
Set # 1149-2: Bulldozer Chainlinks  (nominally 52 links)