Problem with new PX4 Mini

I’ve just received a new PX4 Mini today, but It wont connect to Mission Planner if the external Mini 8 GPS is connected to it. You can upload firmware OK, but the planner itself just wont connect (says it cant find a heartbeat). If you unplug the external GPS it will connect OK. There is obviously conflict somewhere, as with the GPS connected, when you power it up, you don’t get a proper set of boot sounds or LED indications.

Can someone help me please??

(Alex if you read this, You supplied it, I’m in Hungeford UK, but not using this email address or ID.)

Hi Harvey,

You could check the wire colours on the GPS, sometime they are different from different factories.
In particular look for either a TX or RX wire connected to 0v or ground. This will stop serial data traffic and would prevent MP from connecting. (same applies to the SDA/SCL which is the I2C bus)

Here’s some examples, first two GPS only, last one GPS with internal compass

+5v - red
0v - black
RX - blue
TX - orange

+5v - red
0v - black
RX - green
TX - yellow

+5v - red
0v - black
RX - yellow
TX - green
SDA - white
SCL - brown

Hope this helps, good luck

Thank you Steve, that gave me the clue.

Both cables supplied were completely wrong (fortunately no damage has been caused!). In the end, I’ve used the one that came with the gps … on this one the only correct connections were for uarts rx and tx, the others were wrong power included). Also I’ve discovered that there is not sufficient power provided by the usb connection (even with a powered hub!) to support the external GPS.

Having rewired the cable everything seems to be working fine.

Regards Harvey

Hey, sorry to hear about the issues and thanks @stevietee10 for helping out so quickly, thats what the community is all about :smiley:

Do you by any chance have an order number so I can look into this and get the other cabled fixed if needed? Did you buy the mini GPS for PX4, or did you use one of our other Ublox 7/8 GPS modules that come in the circular plastic case?

Hello Alex,

Your order number was 25647 placed under a different name (my real l name) and the email address was my main one, not this one … I don’t use my real name or email address on forums.

As you will see it was for A MiniHawk PX4 Mini AIO V1.4 with mini Ublox M8N GPS Module with Compass. There was a cable in the Compass bag, which was the one I used initially and have this morning, modified to get it working. This morning I discovered another cable labelled for use a and external GPS and supplied with the other cables with the Controller; this one is also wrong.

Hope this helps



Thanks, I will look into that as I assumed first that you possibly ordered one of the other GPS modules we sell and as you can imagine its not possible to have one pin out for all autopilots even though they all basically use the same ublox GPS chip. So I will look into this with the factory as to why they where wrong.

Also next time you want to place an order just send us an email with your account address and mention this thread and I will arrange free next day shipping/extra goodies to say sorry about the cable error.

Hope you have it all working now :slight_smile: