A PIC Keyer
A PIC keyer using a 16F84 PIC has been constructed for use in a number of beacons or as a home station keyer.
Typically it sends "GB3XXX GB3XXX, JO01XX JO01XX" followed by 15 seconds of carrier, but can be programmed to send any message. Component count and cost is very low and it is extremely compact measuring approx 1.5" x 1". Current consumption is a few mA at 12volts.
Output is an open collector transistor.