First off, thanks for creating this forum - what a great resource!
I am embarking on a project where I will be using a wii nunchuck to control a pan and tilt servo assembly. I have a choice of using 120° limited rotation servos or continuous rotation servos. It would be nice to have a bit more than 120° for the polar rotation but that's by the by.
My question is, using a wii nunchuck as a controller, am I better off using one type of servo over the other? As I understand it, limited rotation (or rather standard) servos are controlled by their position via the feedback pot and continuous rotation are controlled via the pulse width and receive speed and direction information only. I have messed about with standard servos and found a way to speed them up and slow them down through a sweep by varying the time interval value between each degree step. I have never used continuous rotation servos however.
Does anyone know which parameters would be better suited to the information that the nunchuck provides? I am hoping that the pan and tilt mechanism can follow the speed and position of the wii nunchuck reasonably faithfully in both position, speed and acceleration.
I will probably need to figure out some kind of calibration method as well so that it doesn't get "out of shape".
I hope to document my project on here once finished.
You are correct in how the servos are controlled. I've done a fair bit of work controlling servo motion through a Nunchuck using standard servos and it works pretty well. There tends to be a bit of latency but it's not too bad and the servos follow the Nunchuck inputs reasonably well. Fast servos can make a big difference in this application.
If you need more than 120 degree rotation what you can do is remove the pot from the servo and modify the servo mechanical end stops (sometimes easy, sometimes hard!) and then use an external pot where the pot is geared to the servo output shaft. Using a 3:1 gear ratio the servo output shaft can rotate 360 degrees while the pot only rotates 120 degrees.
ah nice, I think I may leave the hacking until I am more experienced. Sorry for the late reply, been busy busy, only just got time to come back to this. Thanks for the link I already read your instructable, all looks pretty cool!