Discussions

3DR ver 1 radio to APM connection

Posted by Dwgsparky on January 9, 2015 at 7:45am

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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Replies

Moderator

Dwgsparky January 9, 2015 at 8:26am

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?
- Marcin Krawczyk > Dwgsparky January 9, 2015 at 8:30am
  
  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
    
    Dwgsparky > Marcin Krawczyk January 9, 2015 at 8:53am
    
    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.
    - Marcin Krawczyk > Dwgsparky January 9, 2015 at 9:15am
      
      I'm not sure what you mean. Better take a picture of modules and draw your idea.
      
      But if you expect that you can connect USB plug directly to APM - you're wrong.
      
      APM/PIXHAWK use UART, not USB.
      
      http://en.wikipedia.org/wiki/Universal_asynchronous_receiver/transm...
      
      http://en.wikipedia.org/wiki/USB
      - Moderator
        
        Dwgsparky > Marcin Krawczyk January 9, 2015 at 10:18am
        
        Ok, it was just a thought , now I know why it won't work , time to buy new modules
Marcin Krawczyk January 9, 2015 at 7:48am

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 ;-)