“these continuous rotation servo's are not vastly accurate and you will need to calibrate them if you want to run a pair together; but having said that, they are simple enough to use, they work with the servo phat, and they attach to lego well, and are the right price. documented examples were a bit lacking, but there is at least some out there now :-)
The motor takes about 1 second to turn a full 360deg in one direction and about 1.6 seconds for the same degrees rotation in the other direction. there is a variance of about 10%-15% or so when I checked 6 motors. This was with 50hz driving frequency, at maximum speed in each direction using the servophat python libs.”
“Fits really well with original Lego pieces, which I was worried about before ordering. The Lego axle is very handy, just pop a cog on and you're in business! I used mine to make a focus mechanism for the HQ camera. https://www.hackster.io/martin-mander/focus-the-pi-high-quality-camera-with-lego-and-a-servo-4aec4c”