Problem with Serial Communications Using HC-12 Between Unos

Projects Networking, Protocols, and Devices
1

I am trying to use HC-12 radios (http://www.elecrow.com/download/HC-12.pdf) for serial communication between Unos.

I have proven the circuitry to work by direct connecting the serial ports of the two Unos. I get reliable half duplex communications at 9600 bps.

When I insert the HC-12 radios into the serial chain the communication does not work.

The strange thing is the radios work reliably when using Pro - Minis.

I have checked and double checked the hardware configuration. The code is the same in both cases.

Any ideas on why this is not working or what to do to fix it?

Thanks

2

The Pro Mini doesn't have a built-in USB to Serial connection. Could it be that you have the HC-12 modules connected to RX and TX (Pins 0 and 1) and are getting interference from the USB to Serial chip?

Have you tried SoftwareSerial on two other pins?

3

Thank you very much.
I used SoftwareSerial and it is working perfectly.
As you suggested, it is probably a conflict with the Uno's USB.
Regards