Arduino to Arduino using RX/TX

Hello, I have been working on creating an arduino to arduino connection; basically I want to push a button on one board then send data to another to turn on an led. I crossed the rx/tx wires between boards then used a wire to common ground the pair. The program is very straightforward but it appears as if the board sending will not light the TX light. When the usb cable is connected there is no problem communicating with my terminal, so I believe this is a hardware issue. Any suggestion / solutions?

Have you tried writing code to send and receive data on the boards? Crossing RX/TX wires as you describe should work. The RX and TX LEDs may not light up, but that doesn't mean the data isn't being sent.

I ran into this same situation. My guess is that you're missing the same thing I was - the two arduinos need to share a ground in order to give the tx and rx lines a reference point. Just run a line between ground on one arduino and ground on the other, along with the rx and tx lines, and it should work.

  • Jason