Stuff related to MAV's (and UAV's) from a hobbyist's point of view. Info

Servo controller

After a silent period (which lasted too long), I finally have some news.

I had to tackle some issues concerning the programming of my PICs, but now they work just fine.

This week, I’ve been working on a servo-controller which decodes the PPM pulse train from the receiver and sends pulses to the servos.
Again, I encountered the weirdest problems: My servo moved reeeaaal slow when I made a quick movement with the stick of my transmitter. After days of debugging my code, I found out that the quick movement made the servo-motor use a lot of current, triggering a voltage drop, and the Brown Out Reset of the PIC made the whole thing reset. But now it works fine :-)

The code is written in CCS/C. The most basic code (= 2 interrupt routines) is about 20 lines long, so I still have a lot of processing time left! I also added some basic filtering, which only sends valid frames (with the correct number of channels and a correct synchronization pulse) to the servo’s. This greatly improves the reliability of my old Mulitplex PICO5/6 receiver.

The next step is reading in the analog values of the thermophile sensors and adding a control mechanism to drive the servos. Exciting stuff!

Here some photos of my home-lab ;-)

22 October 2006, 10:22 | Link |