I recently purchased my first autonomous aircraft from 3DRobotics, so I'm fairly new to all of this. I got the ArduCopter kit with the APM2.5 and right now I'm stuck at the point where I need to calibrate the RC inputs in the Mission Planner. I did my best to research this problem but so far nothing has worked. Thanks in advance for your help!! Even a link to point me in the right direction would be terrific!
Here's my setup:
The APM2.5 is connected to the computer via USB. The signal wires from a Spektrum AR7000 receiver are connected to the corresponding inputs of the APM. I have tried everything below with the GPS (uBlox LEA-6), 3DR radio, and Power Module both connected and disconnected.
The receiver is powered by one of the input channels on the APM (via the supplied 2-wire female-female cable). I did this based on the first sentence of this link which says
For the APM 2 this setup can be performed without connecting a battery. (Generally the USB port will provide sufficient power for both the APM 2 board and the receiver.)
Here's what I've tried:
I read the troubleshooting guide here, but the first line of step 1 says
The USB cable will NOT power the RC receiver.
So which is right? I'm assuming this last statement was intended for the APM1 but can anyone verify that?
Step 5 of the troubleshooting guide mentions there have been problems with some Spektrum receivers and describes how to bind with it. However I had no issue binding and was able to control a servo on the rudder channel. Taking advice from step 8, I then plugged only the rudder signal into the rudder input on the APM but still no green bar anywhere on the "Radio Calibration" screen (still connected to the Mission Planner).
Then I looked at the PWM rudder signal on my oscilloscope and the width of the pulse widened and narrowed as I moved the rudder stick back and forth, just as expected. But I also noticed that each pulse had a magnitude of only 4V. I was expecting to see 5V since that's what the receiver was getting from the APM, but I don't know, maybe this is normal. Also the period between each pulse was 22ms for a frequency of 45.45Hz - but again I don't know if this is normal or not. Does anyone know if these values are right or better yet where I can find the expected specs for input PWM signals?
I'm now at the point where I'd like to try to power the receiver independent of the APM. But after looking at the power schematic of the APM2.5 (here) I'm worried about the voltage mismatch between what's supplied by the USB cable (which is made available on the 5V pin of the PWM inputs) and the the 5V line coming from receiver. Though, I suppose I don't need to send over the 5V line from the receiver to the APM (since I'm still using USB) but I do need to connect the GNDs so they'll be common... Does this seem like a good idea or is there something better to try?
As I said above I'm pretty new to this so I'm wondering if I need to do something like reformat or clear the APM2.5. Last night I updated the mission planner and downloaded the newest Quadrotor software to the APM2.5 but still no success. Sorry for the long post! I just want to be clear to avoid confusion.
Thanks for your help!!