Uploaded November 2008 | Updated September 2026, 4 hours ago

Bill mentioned the Arduino on the SolderSmoke blog, and I remembered that I had one floating around unused. A few minutes later, I had coded up a simple Morse beacon sender, and soldered a cable together to send Morse via my trust FT-817nd.

555 Astable Multivibrator as an AM Transmitter

$Arduino, analogWrite, and DC voltages This morning I quickly put together a little RC filter to turn the PWM output of the Arduino into smoothly varying analog voltage to control the VCO in my G0UPL low power beacon transmitter. I think the filter is actually a bit too aggressive, it takes a significant fraction of a second to settle on the new value. Ill get a different cap in there later to speed that up a bit. (Apologies for the soft focus, Ill remember to use the macro next time).$

Hellduino: Sending Hellschreiber from an Arduino

An Arduino powered IBM PS/2 Morse Keyboard