Following on from my PPM Encoder mods (PPM Encoder Updated), I needed to be able to test and tune the main rotor speed controller. I figured that a small setup was needed to simulate the pulses generated by the RPM sensor, that was motor driven and speed controllable by the ACM board.
So on the right of the photo, you see a my RPM test set consisting of plastic bucket lid, with a hole to allow light onto a sensor below. The lid is bolted to a small brushless motor, and the ESC (which I think I just burned out) is connected to the throttle servo output on the ACM.
When it's fired up, the PPM Encoder is measuring the RPM pulse timing and outputting the result to Ch5 into the APM chip. However, due to the method I calculate the timing, the resolution on the RPM speed is useless.
So as far as the PPM encoder mods go - its back to the drawing board.
(The things we do in the name of progress)....
Comments
Well Darren, Jack - I'll take your comments as compliments. Esp when you see the age of the rest of my collection. I think my milling machine was made in about 1920.
But aside from this, I have recoded the RPM timers from scratch and included a much better scaling system to bring the readings in line with the expected PPM output pulse widths.
Under testing with my fancy plastic lid, I get a Channel 5 pulse width of about 1.5mS for about 1500RPM, with enough range on the timing to measure RPMs from about 500 up to about 2200. All with microsecond resolution.
So this is now ready for the PID implementation in the ACM Heli code.
That looks like an original Mac converted into an oscilloscope & that looks like a living breathing CRT monitor. It's like 1999.