Servers by jDrones

Red LED flashing after all pre arm checks complete and armed


(jchello) #1

Hello all,
I have a two quick flash LED that stays on even after all the pre arm checks are complete and the throttle is armed with the rudder.

I can find no obvious source of the problem because everything seems to be working as it should. I have:
recalibrated radio
recalibrated accelerometers
Obtained 3d gps fix with hdop ~2
releveled gyro
Checked mag compass operation and accuracy
checked airspeed indicator
run preflight calibration prior to arming
Tested failsafe (works on ground as it should)
Connected over Mavlink (works fine)

Essentially, I have run out of known tests to try, as the system seems to be working fine with everything up and running and a successful motor arm and throttle response. The way I understand it, if you enable all of the preflight checks to execute prior to arming, any one of these should prevent a motor arm-but I am able to arm fine every time. So any ideas as to what could be causing the red LED flash (2 quick flashes followed by a brief pause, then repeats)?

I can provide logs when I get back home.


(Craig Elder) #2

I’m guessing you are using APM 2.X

This is a known issue in 2.77

It will be resolved in the next release

See this

viewtopic.php?f=88&t=5758


(jchello) #3

Yes this is APM 2.77. I reverted to 2.76 and the problem went away. Is it safe to fly with the LED flashing? Or can I assume that something else may be wrong?


(Craig Elder) #4

Note Tridge’s comments from the other thread:

APM:Plane code, so you will always end up with flashing yellow once everything else is OK, even if pre-arm checks pass. Sorry! I’ll get this fixed up soon. It is harmless apart from the display of the LED colour, so you can still fly fine with the yellow LED.

Yellow on Pixhawk and Red on APM

It is already fixed in Master


(jchello) #5

Thanks much.