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Jan 29, 2008, 01:59 PM
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More servo jitter video 4 U


With Vicaglider's GPS going at 4Hz, the PWM resolution dropped to 18usec. U can see the effect.

Servo jitter at 18usec resolution (0 min 10 sec)


That's why we only soldered 1 servo header. A small, second PIC for PWM looks almost certain. Another trick is seeding PWM calls throughout the main loop but that never worked well.

Endless rain & Vicacopter downtime has us leaning towards sooner Vicaglider acquisitions.
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Jan 29, 2008, 10:31 PM
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I was looking at vicacopter.com


Jack, Herowineworhsiper or??,
This is my third comment on RC groups in the last week, two private, this one public. If you did not see the private ones, I'll try again.

I was looking through the code at vicacopter (actually I looked at ti about two weeks ago) any possibility of adding some organizational notes, like a block diagram with the sensors, PIC, GumStick and actuators? Or at least a description of what goes in /out of where?


Paul
Jan 30, 2008, 12:47 AM
Chris Anderson
Why don't you use a separate servo driver chip to generate the PWM? They cost around $3 and it takes a huge load off the CPU.
Jan 30, 2008, 03:20 AM
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Have receieved all the PM's. Only the README has some algorithm explanations. The relevant function for PID loops is do_pid. The lack of support is explained below. The alternative is just to take it down.

Since Vicaglider is a throwaway, there's no interest in doing PWM interfaces which can't be put into Vicacopter. Could just buy an attopilot for $150 and be done with it.


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