K3NG Keyer complete

I finally build K3NG’s Arduino CW Keyer and put it in a nice box. Here’s how it looks:

K3NG Arduino keyer, complete

That’s a SparkFun Arduino Project Enclosure with two buttons (one command, one macro), a CW speed control potentiometer, and a simple 3.5mm audio jack for keying the transmitter.

Enclosure base, showing piezo and potentiometer

I’ve glued a cheapo piezo (UHU All Purpose glue is my piezo glue of choice; cyanoacrylate is too brittle) onto the base, and cut a hole in the side for the speed pot. The piezo gives a clear enough side tone that I can copy CW (or Hellschreiber, as before) with audio output into Fldigi. The beeper’s got a fierce third harmonic, but that’s part of its charm. K3NG has a more complex speaker circuit, but this is simple and self-contained.

Enclosure lid, with buttons and resistors

Two momentary switches ($2 from Active Surplus) make up the control interface.

Arduino+Protoboard, and the magic of a 2N2222 switch

The clever bit is an Arduino Duemilanove Uno (my oldest board; it deserves a proper useful home which doesn’t seem to have the serial startup problems my Duemilanove had) with an Adafruit Proto Shield on top. The only “clever” componentry on that is a solitary 2N2222 switching transistor.

It works pretty well. The only thing that doesn’t seem to be stable is the memory button; it seems to choose randomly from any of the first four memories, so I might accidentally send an SK when I meant a CQ. For now, until I work out what’s wrong, I’ll stick to keyboard input of the macros.

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