I bought the 3dr arducopter quad kit a few weeks ago, and I have been putting it together. I have a bit of a problem now with the apm 2.5 and my receiver. Here is the scenario:

- USB connected

- Nothing connected on the output pins, or the other optional pins

- J1 connected

- Power connected between apm output and receiver

In this setup, things are fine. I can use the mission planner, connect, and the "horizon" information about how level the apm is correctly relayed back. In this case the "A" led is flashing, tx is flashing quickly, rx blinks occasionally.

However, if I connect the channel 1 signal pin from my receiver (Optima 9) to the "in 1" signal pin on the input side (this happens with any single pin, just using #1 as an example), and reboot the apm, within a few seconds after the boot sequence, the "A" led is solid for a few seconds (it thinks it's armed?), then the pattern changes to "ABCABCABC" (one at a time) sequentially forever, and the mission planner indicates the apm thinks it all of a sudden is being rotated around quickly until it finally seems to stop as though the top of it is facing hard left or right. It still responds to the input in that I can rotate the board, and it will show some movement, but is then permanently stuck thinking a crazy angle is "level". At this point the tx light is almost fully on (flashing intermittently), and rx is blinking.

Again, if I disconnect the signal pin on the receiver from the signal pin on the input of the apm, then it doesn't have this crazy problem. This happens with or without the usb connected too.

Does anyone have any advice? What does that ABCABCABC led sequence indicate? I found a couple of led guides for apm, but neither seems to describe the sequential ABC pattern. 



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  • Oops, I think I may have (somewhat) figured this out. I was trying to calibrate my radio for the first time, which was hit and miss because depending on the timing of things, the mission planner wouldn't show any radio input. Once I successfully calibrated, things seem to be better now.

    I think my problem was the default signal level coming out of the receiver was in the "arm" range of the apm, which is my conclusion because the steady "A" led was on before it went nuts. I can only assume if that signal continues for too long, the apm goes into some kind of special mode to prevent input, or some such thing.

    I don't intend on deleting this, in case any other people stumble on this, unless there are mods here who think it should be deleted. Whatever.

This reply was deleted.


Santiago Perez liked Santiago Perez's profile
2 hours ago