3DR ver 1 radio to APM connection

Hi , Help please

I have several Ver. 1.1/1.3 3DR radios (not clones) with the USB connector. ie. ground modules, I broke one of my air modules and would like to know if it is possible to simply take a female USB cable and connect the 5v,0v,Tx,Rx to the corresponding pins /connector on the old style APM2.0. and use the USB ground module in the air??  

I know it will be ugly and heavier but will it work?? 

Would anything need to change in the 3DR radio configuration?

Thank you

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  • Moderator

    Thanks but I thought the USB ground module was taking the 5v USB supply and changing the voltage levels before sending it to the HM-trp. The ground module has a standard USB PC sized 5 volt connector? 

    • 1. No, connection between USB and UART isn't so simply.

      2. "The ground module has a standard USB PC sized 5 volt connector? " - what do you mean?

      • Moderator

        First, thanks for your help

        The old style ground module on the 3Dr radio has the same USB plug that fits a normal Laptop or desktop PC. I can push it directly into the laptop and set it up OK or use it for telemetry,  the connector has 5V,0vTx Rx on the 4 pins and so I assume that the Tx,Rx are 5 volt as well (dont know) so I want to take the 5v,0v, Tx,Rx from the APM and attach them to a USB extension cable that is cut in half to give me a USB female socket with the 4 wires for the APM2 and I can then plug the radio into the female socket. 

  • No

    If you need Rx&Tx - you must connect directly to pads on HM-TRP. Remember, that HM-TRP is 3.3V powered.

    Bellow some inspiration ;-)


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