No GPS or Pi Zero talk, only power to both

Drone Dojo Kit Building PiHawk Drone Kit
1

Been working on this for a few days now. Attached is the picture of the electronics soldered together per the diagram (with one exception, of flipped TX RX wires on the gps connection while troubleshooting.)

Problems:

  1. Pi-zero cannot get heartbeat from FC
  2. GPS is on but not talking to the FC at all.

What I tried:
I configured the FC via Adrupilot for the PI Z to be on UART 3 (SERIAL 2) and the GPS on UART 5 (SERIAL 3)

  • Telemetry seems to be fine per Adrupilot and the radio syncs just fine

I spent roughly 12 hours with chatgpt and google. Please provide another way forward. I am out of ideas to finish this thing.

Thanks in advance!

CB

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2

Check the following blog and look at connecting the GPS and RPi zero.

Perhaps it will help depending on what fc board is used

3

FC appears to be the F405 HDTE

I actually went through the youtube and the course (as far as i could) thoroughly… it’s just not testing out as anticipated.

4

Did you read my blog?

5

Yes, is there a specific area that you think I should drill down into to troubleshoot?

I will take any suggestions at this point.

CB

6

I underscored for GPS and RPi the fc connections are sometimes irregular, ie, not per the label. I think Caleb mentioned this as well.

7

he did, and based on that, I swapped the TX RX on the GPS connection to the FC. Sadly, same symptoms and ArduPilot still not seeing and GPS.

Would you suggest swapping the TX RX for the Pi Zero also? (I hate re-soldering excessively…)

Thanks for any other guidance or suggestions.

CB

8

Also, there was a separate connector that came on the GPS that had two wires on it. Caleb’s diagram showed these connecting to the last two pins, next to the Power, GND, RX, TX wires. So I connected as shown, although the colors were different, I assumed blue = white, pink = orange… Are these passive? Required?
Could they be the culprit ?

9

So you are soldering the RPi GPIOs 14/15 to Tx3/Rx3 as shown in the red circle?

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And this is how you are connecting the GPS?
The other two wires (SCL, SDA) are for the compass.

I looked at ChatGPT as well. It suggests not to connect the GPS to Tx/Rx5 as in the instructions, but to Serial4/UART4 (Tx/Rx4 - red circle, other side of board) due to a possible conflict with the SBUS communication option. I know Caleb has it working on his board, but this was suggested by ChatGPT.

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Not sure why the Rpi is not working. Yes, I would try swapping Tx/Rx in case there was a board issue. I know it’s not fun resoldering, but it’s a possibility.

Also check this blog https://dojofordrones.com/ardupilot-connection-issues/.

Make sure you’ve confirmed the settings in Mission Planner as per the Youtube (32:45).

If you provide more information on what steps you used and pictures I can try to work on it more.

As a final measure, you can try contacting Caleb on the bottom of the page here.