Where to connect ppm reciever to the board?

[hugy]

Could you post that hex file with the mods. Please.

[hugy]

Got it compiled myself. This is a working ppm futaba hex file. enjoy.

[kinderkram]

Thx!
btw: which receiver do you use?

[hugy]

I use ezuhf receiver on a ff9.

[Max]

Quick question about the PPM input pin-- Can I change the PWM channel used by simply editing this define?

#define PPM_PWM_CHANNEL 13

Or is there more to it than that? I'm already using #14 output due to its convenient location in my setup.

EDIT: never mind... tried it, worked.

EDIT 2: Ah, just have to make sure not to use a timer/port which is already assigned to a motor or gimbal (http://autoquad.org/wiki/wiki/developme ... equencies/).

-Max

[JussiH]

Anyone tried Thomas Sherrrer LRS with AQ yet?

[hugy]

If you use it with a futaba radio, it should work with the code I posted.

[JussiH]

Thanks, my radio is a JR, but I will work it out and post results here.

[Max]

I've tested and have been flying successfully with FrSky PPM and using all 8 channels. I made one mod to the code, and adjusted the end points in my Tx (Evo 9) to output just above the acceptable limits as described in this thread and the (approx. -750/0/+750 and 0/+1500 on throttle). (BTW the flaps/aux2 switch channels only really need to extend -250/0/250 because those are the thresholds being used in the AQ code currently to detect states.)

In the ppm code I simply changed the guard pulse length to 2.75ms. Original was 3.5ms. Other implementations I looked at used 3ms, which worked OK with FrSky but still caused "brownouts" with > 6 channels near maximum. From what I've read 2.7ms is the "official" minimum, so I chose a value just above that. The max pulse width for a valid channel is still 2.25ms.

In ppm.h:30 I changed:

#define PPM_GUARD_PULSE_LENGTH 2750 // was 3500

The only way it looses synch now is with all 8 channels at maximum, which just isn't going to happen (I'd have to set home position (aux2 high) while using maximum deflection on all surfaces and full throttle -- not very likely!). I'm including channel 5 in my tests (I use that as a camera trigger) and my channel 8 (camera tilt) is set to use full range in the Tx.

Green flat line @100 is RADIO_QUALITY; Each channel taken to max throws in turn: throttle, rudder, aileron, elevator, aux3 (8), flaps (6), gear (5). aux2 (7) stays at neutral. Then each channel returned to neutral/low. Then Tx is switched off and turned on again (with throttle lock active--hence low throttle value).

I don't have any "before" graphs, but with the guard pulse at 3.5ms it would brown out (loose synch, radio quality zero) well before maximum deflection on anything over 6 channels (I think I even got it to die with 6 channels on max but that was with my original Tx end point adjustments). At 3ms (PPM_GUARD_PULSE_LENGTH 3000) it was usable but should be very carefully tested to understand which extremes to avoid. And adjusting the Tx end points is vital.

Any opinions on this solution (hack) for the FrSky issue?

-Max

[Max]

What is the difference, if any, between adjusting the scaling values in ppm.c to get the desired output ranges, vs. adjusting the end points (throws) on your Tx to get within the acceptable ranges?

Thanks,
-Max