I’m trying to get my lift sync working, and I’m using pots. I’ve seen many teams using shaft encoders, and I’ve heard about pots not being the most effective way to atempt a lift sync due to the wacky values. So my question is whether to use pots or shaft encoders to do a lift sync and how I should approach it in easyC.
From what I understand, a pot returns a measure of voltage, which will end up being proportional to the angle of the axle. On the other hand, a shaft encoder effectively counts the number of slits the light passes through on the disc, allowing you to count and figure out the direction, speed, and distance that an axle travels. In my opinion, a lift sync would be better off with a pot because you can turn on the motor whenever the axle moves in an unwanted direction
You can use either, here are the pros and cons.
Good - Absolute position, no need to reset
Not so good - can return bad values if worn out
Nor so good - Can only rotate through 220 degrees
Not so good - It’s an analog device therefore there is some noise on the value returned.
Good - Multiple rotations possible
Good - values cannot jump by large amounts, that is, it’s a counter, there is no direct measurement of a voltage or anything that can be noisy
Good - IME is mounted on the motor
Not so good - relative, count starts from the position at which it was turned on.
Not so good - Quad encoders are larger
Not so good - IMEs can be temperamental.
Jpearman hit most points I would mention. From my experience both will serve the application quite well. I find that potentiometers can yield a bit more fidelity in its readings due to readings from it ranging from 0 to 4096 in its 220 degrees of motion rather than encoders that are sub 1000 ticks in a full rotation. My biggest qualm with pots is their failure rate, but that is likely me just having bad luck with my purchase orders. Some failure cases are managable with the right filter though. IMEs have their own failure mode when the I2C line gets hammered with ESD, and that one is not as easily rectified.
If your gear ratio allows for good fidelity from encoders they provide a nominally more stable signal. Otherwise potentiometers will give you a good range of values to work with.