I'm running the APM2.5+ with Arducopter 2.8.? (The version before 2.9)
My Radio is a Spektrum DX8.
All of the radio calibration went fine, but I noticed at the time of calibration that the throttle 'green bar' would randomly blip up to half throttle (or if it was at half it would blip up to full).
At the time i thought maybe it was just because i was inside and usb tethered.
Motor testing without props though verified that occasionally the motors would briefly double speed then drop back to idle or half speed. this was random again, no pattern, once every 5 to 15 seconds.
Fool that I am i thought maybe somehow attaching props would solve this issue, but again, at idle the motors would pulse enough to just lift frame, or if I was almost at takeoff speed the frame would jump up and flip.
I've noticed one issue of uneven thrust front to rear which I think is due to different quality props (front coloured ones appear stronger).
But the throttle pulse/blip thing is my primary concern.
Has anyone else experienced this?
I saw a thread somewhere about flashing the 32u chip to help it keep up with the high speed of futaba 8 channel sets, would the same fix help me? I am only skeptical about that fix due to my board being so new surely it has the latest file in the 32u chip? (The post about the flashing was from 2011).
I've ruled out the tx or rx being the issue as the motor speed is completely stable and constant when powered directly by RX,
SOLUTION (SO FAR)
Changed data rate to 11ms instead of 22ms, the throttle blips have disappeared in the 5 min test i did in the workshop, more tests tomorrow to get conclusive results, but it's looking great so far.
Many thanks to J B for suggesting this fix.
I think I am seeing the same issue with different Spektrum gear. It popped up when I connected the gear channel to the Ardupilot: http://diydrones.com/forum/topics/spektrum-pwm-read-issue
So my setup cannot be put into 11ms mode. Is anyone else having this issue with DSMX receivers? I dropped down to 4 PWM inputs and it may have helped the issue slightly but I'm still getting glitches in roll PWM values over 1600.
I solved my problem regarding the behavior of Spektrum DX8 Rx problems.
My setup is DSMX, 22 ms frame rate.
In order to validate that no channels are "glitching"... I used the Mission Planner Radio Calibration Tab and watched the "red lines"... If you ever did calibration you know what I'm talking about. Basically MP will track any changes on the channels.
Yaw peaked at 1907 because I did Arm the motors. Throttle did go to 931 since I tested the Fail Safe.
Channel 7 never moved.... (for me, glitches were on Ch#7). No wonder why my Quad was unable to finish mission since Chan#7 was configured to RTL :) ... the glitches were occuring every 15 secs or so.
I solved this nightmare by upgrading APM2.5 PPM Encoder from version 2.2.65 to 2.3.13.
I followed these fine instructions.
Note: Be aware that when you short RST to GND, make sure Windows is switching USB drivers. Yes you hear the sound but make sure the driver is working! I used Flip 3.4.7 to do the "flashing". I used USB Drivers found in the package. I'm on Windows 7.
I hope I'm not missleading anybody here.
Thanks for the link to the flashing instructions. I am trying it right now and I cannot for the life of me get the PC to switch to the USB driver for the Atmel chip when I do the reset. I get the Disconnect/reconnect sound, but it just re-mounts the main Arduino Mega 2560 drivers. Any suggestions?
Scott It work for me using the usb driver under the usb subdirectory of Flip 3.4.7
make sure you have a good connection for J2 jumper before the reset.
I'll try again. It never seems to see the Atmel chip on the connection. Maybe my jumper is faulty. time to get out the meter I guess.
USB driver for APM is not the same as Flip use.
During my tests I had some problems with faulty jumper...
...not sure that you need the meter.
I install J2 before connecting the APM to the USB port of my PC.
Short RTS to GND ... and another driver is use.
OK - this is what I am doing/seeing.
1) Jumper on J2, board connected via USB to PC
2) Red LED is flashing, green power LED is on solid
3) On the PC, in the device driver, I see:
I touch a jumper wire to the two pads and hear the USB disconnect sound and see this in the Device Manager:
4) If I keep the pads shorted, nothing more happens
5) If I release the short, I hear the USB connect sound and the Arduino reconnects using the stock drivers as above.
At no point do I have the option to tell it to connect using the other USB drivers.
When windows asked me to locate drivers... I pointed the usb subdir in Flip.. Maybe try to remove Arduino driver and start from scratch regarding drivers for Windows. Not sure what to tell you to help....