Uploaded November 2009 | Updated September 2026, 4 hours ago
I did this once before, but didn't have the code around, so I redid it, making the code a bit more general (it can send arbitrary messages) and also archive it on my blog at tinyurl.com/yaudhs9 which you can visit for the simple code. To make it actually key the transmitter, you'd need to add a switching transistor, but that's pretty trivial. A future version will also use the PWM to emit an audio tone. Enjoy!
I did this once before, but didn't have the code around, so I redid it, making the code a bit more general (it can send arbitrary messages) and also archive it on my blog at tinyurl.com/yaudhs9 which you can visit for the simple code. To make it actually key the transmitter, you'd need to add a switching transistor, but that's pretty trivial. A future version will also use the PWM to emit an audio tone. Enjoy!
