Pixhawk 2.1 External Module Issues

Hi All,

I’ve been through as many forums and webpages as I think I can handle but I’m getting nowhere.

Have a bit of a frankenstein drone in the making, mostly working but struggling with a few things.

I have the pingrx ADS-B module plugged into Telem2.

915mhz telemetry radio is connected to Telem1, it works and I can connect to the drone and see data through Mission Planner.

I also have a MinimOSD module (to send telemetry to my FPV monitor) and PRM02 (to send telemetry to my controller) connected into Telem1 also, the TX lines on both modules are not connected and RX is connected to the Telem1 TX output as I think it’s supposed to be.

I’m not getting any telemetry data to either the MinimOSD or PRM02.

Second issue, I’ve got external RGB LED’s connected, they’re wired into the I2C port. They work, until the HERE+ GPS Module is plugged in. Once that GPS is plugged in (GPS1) the navigation LED’s switch off and the GPS Module internal LED’s switch on.

Really hoping someone can help its doing my head in bigtime.

I’m going to try a few things with this…

I’m going to move the MinimOSD and PRM02 off the Telem1 port and leave that dedicated to the 915mhz Telemetry Radio.

I should be able to run the OSD side of things off the unused GPS2 Port.

I’m also thinking of moving the LED signal off the I2C bus and onto the SDL SCL wires also available on the GPS2 Port.

Will update after I’ve tried those things…

Ok so the above ideas were a fail… Moved LED’s over to GPS2, same deal - plug Here + in and external Nav lights turn off.

Also moved MinimOSD and PRM02 over to the GPS2 port, still no data showing on either FPV or AT9 receiver.

Running out of ideas now, help!!

Hi Brendan,
I ve got the same problem with the external RGB LED. When my HERE GPS is plugged in, the LED won’t work. Could you find a solution?
As I can see, other people also have this problem:

Hey felix, still no luck with mine as yet mate

Hi Brendan,
sorry to hear that. I’m wondering if it’s just a simple problem with the I2C address. Maybe it would help to change the address of the LED-Module? But I don’t even know if the device supports that…

Don’t think it does, I also tried to take it off th I2C bus and use the GPS2 port which had the same result as soon as there HERE+ GPS Module was plugged back into the GPS1 port

As far as I understand, that’s because GPS2 internally uses the same I2C bus as the I2c 2 port. But GPS1 doesn’t, right? So why does a device on GPS1 port affect the LED module on I2C 2? Do you have an idea?

Unsure :frowning:

Are there any developers that read these posts that we can get to look into this? It has been doing my head in for over 10 months now!!