The meanest of servo jitter!
February 20, 2009
Working on a project, where I want a servo to rotate/position a laser that is reflected to a mirror, that is vibrated by magnetic pulses.. every day stuff here on LMR :)
Earlier I posted this:
- And now it was time to hook it up.
However strange things happened. When I was pulsing the mirror, the servo was moving!
I thought that
* I had hooked up something wrong
* I needed (more) seperate power supplies
* Wires where too close to each other, or spun around each other so the servo got signals that way
* The Microcontroller got some feedback from the magnets, and reset
Eliminating one after the other, I ended up hooking the servo up 100% isolated, only giving it power on the 2 lines, on a stand alone power supply.
Then, by another battery pack, I simply tried to give voltage to the coil, and see what happens on the video!
It even "works" when the coil is getting very little power (on the video it's just getting hard core 5V).
The materials between the coil and the servo are non-magnetic, and the coil is 10 cm away from the servo!!
Now I have proof tested this, and aparently, a coil and a (strong) magnet - which is what is in many motors(!) can cause the servo to freakin move!
Dammit, I have to find another way of pulsing the mirror, this is the hardest, most evil case of servo jitter I have ever experimented! I would not believe this if I did not see it, but it is true, unfortunatly.