Friday, October 2, 2020

Gherkin Express TH 2

Second version of the through hole Gherkin Express

Main changes from the original Gherkin Express TH are the miniature 16MHz crystal and the mini USB connector is moved inwards to be flush with the edge of the PCB. The zener diode footprint is overlapped with one for a blue LED.

The switch positions and LED cut outs are the same as the first version.

I made a new top piece with the legend in the top copper layer instead of the silkscreen layer. The resolution of the copper layer is much higher than the silkscreen. Green, blue, red and yellow soldermask is translucent and the legends can be read through them.

M2 spacers with M3 unthreaded spacers. With the shorter crystal and a smaller 3mm diameter power capacitor laid down on it's side, everything fits with 4mm spacers.

The two zener diodes were replaced with rectangular 2x3x4 (4mm tall) blue LEDs. The power capacitor on this one is a 4mm diameter solid polymer capacitor.

Blue PCB top piece. This one is 1mm thick, the green one was 0.8mm thick. It is a bit stiffer but does not make that much of a difference.

4mm spacers and a 1mm thick nylon washer between the bottom PCB. The top screws are 3mm and the bottom 6mm.