Trouble Shooting

A project log for Ultra Servo V2.0

The intent behind the Ultra Servo is to give a maker or a robotics a powerful building block.

patchartrandpatchartrand 08/14/2019 at 02:560 Comments

I had the servo assembled and ready to start running the program that I wrote for the first iteration. Annnnndddd it would not move, just buzz..... What could limit the power to the motor? Obviously the first thing is the program is wrong. So I had code to send full power to the motor as startup. Still nothing. Ok, must be a bad board not sending the signal to the board. Nope, all is fine..... Ok, a signal to my mosfet is grounding and not opening. No conductivity between the gates and anything else. I have a current chopping feature on the TI DRV chip. Perhaps I miss calculated that value? Math checks out so I take off the resistors and wire in some wires to bypass this feature. Still nothing. By this point I had assembled and disassembled the servo 4 times. While it was probing around with the oscilloscope (looking for any information at this point) I noticed that when I touched the servo it would speed up slightly. So I then started poking around and then I touched the film between the board and the mounting case. Then I could make it go full throttle or almost to nothing by flexing the material. It turns out that the material that isolates the board from the aluminum sub-frame is slightly conductive. Who know (I definitely did not). Lesson learned, only use quality parts!