I have assembled an APM1 and IMU from the kit and now I'm trying to configure everything using the Mission Planner software. The firmware uploads (version 2.7) and everything seems to be working (GPS locks and shows location on the map, accelerometers show tilt on the gauge, etc.).
When calibrating the radio the issues start. The sliders in the Mission Planner showing the radio inputs seem to change every once in a while but not to logical values. Moving the sticks on the radio don't change the sliders in the Mission Planner. The radio works fine, tested with servos and also tested a different radio but still had the same issue.
On other threads users have said that soldering errors can cause this. I checked everything on the APM1 and the IMU and the only thing I could find was between the GND pin and the PE6 pin on the IMU. The multimeter showed 0.3 ohms between those two pins, an edited photo is attached to show the pins I'm talking about. Is that normal or have I made a soldering error? A thorough visual inspection of the APM1 and IMU shows no shorts on any of the solder joints for the pins.
Any suggestions on where to go from here would be greatly appreciated! I'm not sure if this is something I've messed up or if the APM1 or IMU is defective (kit was purchased from the store here). Or maybe something else if I'm barking up the wrong tree. Thank you!
I've tried many things, different power sources (BEC, battery pack, 7805, etc.), different radios, different firmwares, the works. Not sure where to take it from here short of finding a different autopilot because if I can't get past the configuration and radio issues I can't fly with it. Any help would be greatly appreciated.
After flashing the PPM firmware I'm giving up on the APM1. The PPM firmware flashed successfully but the problem did not go away. Time to find another autopilot I guess. Would have been nice to see it fly at least once though.
You might get more help if you post a log. You didn't give anything to go on.
I didn't know there was such a log (new at this). Looking into how to access the log right now.
I'm looking at the logs but they don't seem to have any information relevant to the problem from what I can tell. Here's the head of the log.
Free RAM: 722
DATA: 10, 4.500000
DATA: 11, 0.010000
DATA: 12, 0.180000
DATA: 13, 0.000000
DATA: 14, 0.005000
DATA: 15, 0.000000
DATA: 16, 0.200000
DATA: 17, 0.000000
DATA: 18, 2.400000
DATA: 19, 0.170000
DATA: 20, 0.000000
DATA: 21, 30
DATA: 22, 2.400000
DATA: 23, 0.080000
DATA: 24, 0.400000
CTUN, 0, 0, 26, 0, 0, 0, 94, 0, 0, 0
ATT, 17180, -57, 20944, 45, 27971, 4, 0
And you're powering the board with 5V from the output RC rail? If so, the only thing I can think of is a fried multiplexer.
Out of curiosity, why did you go for the APM 1 kit and not the cheaper and pre-assembled APM 2? User soldering errors (bridges, shorts, missed pins and cold joints) is the #1 cause of problems with APM 1. It's relatively easy to fry things or miss pins, which is why we simplified things so much with APM 2.
The board is powered from the 5V RC rail. So is the APM1 salvageable if the multiplexer is bad? What causes a bad multiplexer? I went with the APM1 because at the time it was the only APM, it was purchased over a year ago but I have been unable to continue the project until recently. The solder joints have been thoroughly checked out with magnification and continuity and are not shorted, crossed, missed, or otherwise bad. If possible I'd like to salvage it but placed an order for an APM 2.5 earlier today out of desperation (stings to shell out over $450 at this point and wait another month) but I'd like to see it fly after having come this far with it. Thanks for your reply!
I'm not sure how to fix a fried multiplexer, but the good news is that it's on the lower (cheaper) APM base board, not the more expensive IMU shield. If you want, I've got an old 1280 base board you can have to test to see if that's the problem. You won't be able to fly the latest ArduCopter code (which requires the 2560) on it, but it could at least reassure you that we've found the fault and can safely get a replacement base board.
After extensive troubleshooting I tried a different 1280 based APM with a stripped down ArduCopter 2.6 firmware at which point everything worked perfectly and the radio funkiness was gone (thank you, Chris!). It seems that the multiplexer was bad/fried/possessed. I ordered another 2560 based APM from the store which arrived today and everything is working great with ArduCopter 2.7.1 firmware. This weekend I plan to mount a GoPro HD HERO2 camera and shoot some video. Wish me luck!