This is my third eTap2hw unit - yes, I know, I'm addicted
It combines the Chinese 6N3 valve preamp that Ecca uses in his valve units, and the Arduino Uno and associated hardware that I used in my second unit. Piet's eTap2hw module is mounted on one of Ecca's Eccamatic pcbs and the Arduino controls the echo module, selects presets and allows for settings to be stored as user 'patches'. Presets can also be selected using MIDI or stepped through with a simple foot-switch.
Further details are in my blog
http://echotapper.wordpress.com/Thanks to Ecca, Piet, Johan and Steve for their help and encouragement in building this unit.
Phil.