View of the Back Side Where 9mm Alpha POTS Are Mounted
Component Side View
The board layout is tight but very doable. It is designed to fit easily in a 1590BB enclosure and also will fit on the expresspcb’s cheapest prototype service fixed size 2.5 x 3.8 board (3 boards for $59.00 delivered ).
Here is the link to the expresspcb layout: (use the big gray “download this file button”)
The Associated Schematic is here:
Couple of notes:
The Blue LED I use has a very high turn on voltage of more than 3V. If you use another type, R13 will definitely need to be increased perhaps to 2.2k or greater. The part I used is from Digikey and the part number is OVLLB8C7.
The design uses 9mm alpha pots mounted on the back. Others can be used just connect wires to the pin connection holes on the board.