Uploaded November 2010 | Updated September 2026, 5 hours ago

It arrived! For years, I've been thinking about trying to learn digital design using FPGAs, and finally during a talk at this year's Hackers conference, I decided to bite the bullet. This is a Xilinx Spartan 3 based board with about 100K gates: should be good for getting started.

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

Scrappy Introduces My Arduino/Gameduino Satellite Tracker