We've changed the channel that reads the throttle on basic ArduPilot from pin 13 to pin 11. That's because pin 13 shares an LED, and it's causing problems with some low-voltage RC receivers. Pin 11 is clean.
The above picture shows the correct jumper wire configuration. If you've been using pin 13, please switch it to pin 11.
In the code, you tell ArduPilot which pin you're using with this line:
//3-1
#define THROTTLE_PIN 11 // pin 13, or pin 11 only (13 was old default, 11 is a better choice for most people)
Sorry about this messiness, but it's all in the service of extracting as much utility as possible out of the basic ArduPilot board (which was originally designed not to control the throttle at all--those were simpler days!). Later this year we'll release a new version of the ArduPilot board which will clean up everything nicely (same features, so nobody will be left behind), but for now, please whip out your soldering iron and switch the jumper.
The manual has been updated with the new instructions.
Comments
Happy to report I had my first flights today with Ardupilot installed. I was using r1385 and tried Stabilize and Fly By Wire A. The good news is both modes worked well without any change to the PID loops. I have made the switch to pin D11 for throttle, and removed the LED connected to pin D13. Removing the LED from D13 definitely fixes the issue with crazy fluctuations in the PWM values. The bad news is I'm still having an issue with the throttle increasing from 0% throttle in Manual to 20% (apx) in both Stabilize and Fly By Wire A. I ran Debug_Subsystem 1 & 2, adjusted my min/max values for ch1-4, reloaded the code and still have the same issue with the throttle. The throttle is also still giving a momentary blip when you first power the board, and when the control surfaces wag.
I'm going to recheck the settings on my ESC and transmitter tomorrow, hopefully I'll find something to explain the throttle issue, but I'm not very optimistic about that possibility as everything works perfectly in manual and I know the ESC is using fixed endpoints, not auto calibrate. Anyway I'm moving forward not backward!
Nathaniel
If we move the throttle to pin 11 (which is definately the right thing to do), does that me for those of us that also have rudder wired in that will need to be on pin 13 now (im guessing the code knows this if we have defined throttle on 11), will rudder not have intermittent problems because of this LED??
Regards,
Tony
That's right. If it's rock solid for you, there's no need to change. But do keep in mind that we'll be changing the default in the code to 11, so you'll have to change that to 13 (along with your other configuration changes) when you're loading new code.
But if you can spare a minute, changing it to 11 is a safe bet and will spare you one more configuration changes with each flash going forward.
Since we can define the throttle pin, if we have it working correctly with pin 13, then there is no need to change to pin 11?
Regards,
TCIII