Ham skills prevail in this year’s LayerOne badge hacking contest. [Jason] was the winner with this Morse Code beacon hack.He got a head start on the competition after seeing our preview feature on the badge hardware development. It got him thinking and let him gather his tools ahead of arrival.
The hardware is segregated into two parts of the board. The lower portion is a take on the Arduino, and the upper portion is a wireless transmitter meant to control some cheap RC cars. [Jason] figured this was perfect for conversion as a CW beacon (continuous wave is what Morse Code is called if you’re a ham). The first issue he encountered was getting the badge to play nicely with the Arduino IDE. It was setup to run Slowduino firmware which uses the internal oscillator. [Jason] soldered on his own crystal and reflashed the firmware. He found that the transmitter couldn’t be directly keyed because of the shifting used in the RC car protocol. He cut the power to the transmitter, and found that it could be more accurately keyed by injecting power to one of the other pins. Check out the video after the break for a better explanation of his technique.
I still don’t understand what it does. Where does the CW source come from?
The arduino turns the carrier oscillator (a super-simple transmitter, if you will. ) on and off. “OOK,” on-and-off-keying, is another term for CW. Arrange that on and off into the particular pattern, and you have Morse. Again, done by the arduino.
Recall that whether or not you hear dahs and dits, or “chunk-chunk-chunk” is actually a function of the receiver, not the transmitter. Make sense? -Jason