Three different routes: * [Pre-made IC, the SKC|http://kd1jv.qrpradio.com/skc/SKC.HTM]* Or, do an AVR version.* Or, do an AVR version. Which, of course, [someone|http://kd1jv.qrpradio.com/butterfly_keyer/Butterfly_keyer.HTM] beat me to. * But, it should definitely not be too tough with discrete components that has: ** Speed control (5, 10, 15, 20, 30, 40 wpm ?) ** No memory needed. ** ...