Our team wants to use a gyro to set the angle on the shooter. Should we do this? We want to set at three angles: pickup is zero degrees, shot is 70 degrees, and carry at 110 degrees.
I think you could, but why not just use an encoder or two stacked pneumatic cylinders to get your angles?
Gyro drift could be an issue.
Because we have no cylinders on the bot and no room to add them, and we are using a window motor, so the shaft is not long enough for the encoder.
Could you stick a 1/4" bore versahub wherever the window motor is mounted to (like on a 2x1) and use that to attach an encoder?
Probably not. See question below:
We want to set at three angles: pickup is zero degrees, shot is 70 degrees, and carry at 110 degrees.
What accuracy do you require?
If your shooter axle is live, could you extend it and mount the encoder there?
Or if not, did you consider mounting the encoder (or pot) off-axis? Or perhaps use a strategically-mounted string pot?
You could try adding an encoder offboard the shaft (if it is not live) and use a small plastic gear and chain mounted to the shaft to drive the encoder.
Additionally, You could also use three limit switches if properly mounted with your setup.
What everyone else said, but potentiometer or absolute encoder instead of just an encoder, unless you can guarantee the shooter will always be at the same angle. Most encoders are incremental, so their zero position is wherever they are when your robot code boots up. Or reboots, if there’s a serious brownout.
We drove a potentiometer via a three bar linkage before, when our frisbee platform pivoted around a simple hinge and was driven with a leadscrew. One arm attached to the potentiometer shaft, then a linkage from there to the shooter platform.
I agree. Since the required travel is only 110 degrees, a standard linear pot is a great solution if you can couple it to the end of the shaft away from the motor.
We were able to use a gyro last year in testing (no live axle). It seemed to work decently enough. We didn’t go with that end effector so we didn’t use it in competition. Just remember your robots angle will affect it.
It is fairly easy to throw a window motor on a drill press then drill and tap the end of the shaft. Stick a threaded rod in it and it can be as long as you like.