The DuinoVOX Arduino powered digital modes USB interface for ham radio.
I designed and built this last week. I wanted to use an Arduino in a ham radio project. It came out so well, that I've decided to publish it here. If you build it and like it, please let me know.
Below is the schematic. I did a youtube video on the project, watchable at this link.
C1 and C2, I used non polarized caps since I had them on hand, but regular electrolytics will work fine. If you're concerned about isolation, you could use two 600:600 Ohm transformers instead.
C4 is not critical. If you don't have a .22, put two .1 in parallel
R7 and R8 don't have to be 10K, can be anything from 10K up, don't have to match either.
C3 can be anything from 1uf up to 10uf
One important tip on using this interface. On your computer, you'll want to set the playback volume for the interface sound card to maximum, then use the drive control knob to set the audio level to your rig. This gives the vox circuit plenty of audio to work with.
The Arduino source code is pasted below. You should be able to copy paste it right into the Arduino IDE. If you have trouble, let me know and I'll email the file to you. Thanks and 73.