QRPGuys Mini Keyer V1 – $15
The QRPGuys Mini Keyer V1 is a very small basic through hole component design keyer to install inside a rig that does not have the keyer capability built-in. Small in size 1.125” W x 1.625” L x 1/2” H, 13 grams (.44oz.), it mounts by drilling two 1/4” dia. holes for the 3.5mm paddle input and aux. jack 1/2” apart. It is powered from the rig, (9-15VDC), and draws only 1mA. Supplied are all the components and PCB, with three remote push button switches to be mounted at your discretion for message initiation and programming. The keyer has adjustable speed from 6WPM-45WPM in 31 increments. The speed setting is stored in the PIC EEPROM, so it is not lost when you turn the power off. There are two programmable memories at (63 and 55 characters), continuous playback mode (beacon), and a 30 second “Tune” mode, that can be stopped by tapping the paddle. The PIC16F628A program is in the public domain and available for modification.
The PIC chip is in a socket, not locked, and can be easily reprogrammed. There is an onboard piezo speaker for transmitters without side tone, which can be jumper disabled for those rigs that do. The keyer uses solder pads for connections to your rig, and a 3.5mm stereo jack for connection to your paddle. The tools required are a soldering iron with a small tip, rosin core solder, small side cutters, and can be built in an hour. On a difficulty scale of 1 to 5, 5 being the most difficult, this is rated at 2.