[FIXED] Problem: Reach M+ won't power up correctly when connected to Pixhawk 2.1?

Hi All!

i’ve just entered into Emlid products. I plan to integrate them into my UAVs powered by Pixhawk 2.1 + Here GPS. I’ve loaded Arducopter 3.5.7 onto it and configured as docs (“ardupilot integration”) says.
I’ve bought two Reach M+ to mount on drones and one Reach RS+ to use as Base.
I’ve a problem with the reach M+

  1. Firmware image and ReachView version. --> 2.14 for every Emild receiver
  2. [System report] N/A
  3. Detailed problem description. How does observed behavior differ from the expected one?

I’ve powered up the two receivers with usb cable connected to my laptop and everything went well, including APP upgrade and config. Then unplugged from usb and connected it to autopilot within UAV, with a cable which connects the “S1” port with the “TELEM2” port of pixhawk. I wired it as:
VCC: to Pix’s VCC
TX: to RX
RX: to TX

Basically, i wired it “mirrored” to the pix pinout:

i hope i explained well, i can make a picture if needed. I could not find clear specific pixhawk wiring instructions on the Emild doc site, but only reach port pinout.

Reach M+ seems to not power up correctly.
only the leftmost orange LED lights up. No blue and green. No matter how long i wait.
I think autopilot is not detecting it, thus it loose GPS fix and even connection after some minutes of staying powered on, then goes crazy (EKF errors, loose position, etc). Strange thing, while it loose GPS data, every led on the drone turns off, like it’s powered down, but i still can see it connected through mission planner.

If i disconnect Reach M+ from UAV and connect again through usb, it came back to normality.

Although wiring could be wrong (the comm part, i think the power part is ok), it should come to life even if wired to VCC and GND only… i’m very puzzled …

Pls help!

Hi Steve,

Seems like Reach is not getting enough power.

By the way, have you seen Ardupilot integration guide in Emlid docs?

Hi Dimitry,

i solved the problem. It was faulty cable. Also, Reach M+ can ONLY be powered directly from Telem1 port, any other port will produce my error, even with a good cable, maybe due to weak current supply.

To entirely solve the problem, i added a Polou 2A 5v regulator which takes power from PDB directly, only to power the Reach unit, connected to the VCC/GND wires. Now unit is working OK and i can use other port than Telem1, which currently is used for the 433 telemetry datalink.

Suggestion for Emlid:
provide a ready to use “integration” cable in the box, which have a small regulator inside itself or a Y-split connector to provide an external additional power supply. Make clear in the docs the power supply problem and wiring scheme of the cable.


Hi Steve,

Glad to hear you’ve found the source of problem. Thanks for sharing the solution.