cannot connect 3DR radio to Arduino Uno


I'm trying to connect the 3DR Radios to my Arduino Uno board to do wireless communication.

My first example is a simple echo code which just echoes the data back. But the echo does not work. When I type something on the terminal I see the Tx (red light blinking) happening on the "Ground" radio but there is no corresponding blink on the "Air" radio.

The Air radio's +5V, GND, Tx and Rx cables are connected to the corresponding ones of the Uno and the Uno is disconnected from the USB and powered by an adapter.

The Ground Radio is connected to the computer on COM6 and the green lights on the both the Ground and the air radios are on and not blinking which seems to indicate that they have connected.

I had to install FTDI drivers to get the Ground radio recognized by my Windows 7.

Any help to get this working would be much appreciated!



---------- Arduino Code -------------

void setup() {

void loop() {
  if (Serial.available()) {

-----------End Code ------------------

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  • Hey,

    We are trying to do something similar:, however we want to use mission planner?

    Where did you connect the 3DR radios to the uno, analog input/digital pins?

    Also, we hope to use the mission planner to talk through the radio - any thoughts?


  • OK figured this out after reading about the basics of Serial communication here:

    I was connecting Serial Tx to Tx and Rx to Rx on the "Air module", which is wrong. Rather it should be Tx to Rx and Rx to Tx.

    Fixing the wires as above and rerunning the 3DR Radio Configuration Utility, the above Arduino code works.

    Also need to make sure that all the baud rates are the same: The local and remote baud rates in the Utility, the baud rate specified in the code above (Serial.begin(...)) and the baud rate in the Serial terminal.


    Serial Communication -
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