One inch deep vs 0.6 inch tall? Which is the diameter of the hole?

One might consider a different arrangement of the circuit board. Like mounting the batteries on a circular PCB connected at right angles to a second PCB that contains the LEDs and an ATTiny45/85 programmed for the effect you desire.

 

Diameter 1 in. with guide rails for PCB. Depth 1 in. PCB 1 in. X .9 in. Picture in post # 16.

 

Diameter 1 in. with guide rails for PCB. Depth 1 in. PCB 1 in. X .9 in. Picture in post # 16.

Thanks! I somehow missed that post. Possibly because the pic was in an external link.

My idea still applies.

 

For the very lay mind, how does that compare to the version Bernard presented (which I think probably looks mostly like what is currently there)?

Also, coding the chip wise, what is the 'easiest' chip package to code suggested here - or is it effectively all about the same?

 

For current drain measurement, remember the strip of paper that you removed from between the batteries, then replace the paper as if changing batteries but add a fine wire top & bottom.Connect mA meter to wires, tap ckt. board & measure. It is easier if you have copper foil tape for the wires.