deep red PCB

Using ExpressPCB, I designed the circuit board. After a few iterations, I got everything into a pretty compact space.



This version features the large capacitor in the centre. It looks like there is interference but I plan to lay the cap down horizontally.

Conversely, to help reduce footprint, the R3 and R4 resistors are upright, vertical to the PCB.

S1 is the right-angle socket dohickey from Digi-key. P1 is the 100k pot. And U1 is the 555 timer, of course.