What is a Enocder sensor ?

[mechanicalbrain]

Originally Posted by EricH

Do you want encoder or gear tooth sensor? A gear tooth sensor counts gear teeth outside of it (say on the sprocket half an inch away) using a magnetic field, but an encoder, as far as I know, counts how many times its own shaft rotates (oh wait, that's a potentiometer...or is it?) using something similar.

An encoder typically refers to a optical sensor that reflects a infrared beam off a disk with an alternating black and white pattern. The nice advantage over a gear tooth sensor is that by changing the pattern. You can determine the direction the wheel is rotating (though on second thought you can do this by recording direction through the speed controller) by monitoring the pattern. They're both good but I like the optical encoder more. Here's an example of a disk.

I would like to end this by saying that often these type have questions can easily be answered by googling (especially google image) with the info you have.