And now the pcb
Initial debugging complete, I knocked up a pcb for the bistable light switch in the kitchen.
I used CadSoft’s wonderful free Eagle layout editor to design the board.
– and I feel the need to apologise to CadSoft right now if I have broken the free licence by writing about this on a blog associated with a commercial website.
Eagle is a delight to use although, however many times I have tried, I have never managed to create my own component descriptions for the oddities left in my parts bin.
The result was laser-printed onto Press-n-Peel transfer paper, which took three goes before I got a good etch-resist pattern onto the copper – and I still had to touch it up with a pen before etching.
I don’t think this it the fault of the paper. It just takes practice to iron the transfer onto the copper without messing-up.
And you have to work out which Eagle settings and which printer settings give the highest toner density.
As far as I can make out, within Eagle you have to set both tack and pad colours to white, as well as ticking the ‘solid’ box for the best print.
Etching, drilling and cutting to size all went pretty well, and the complete board works.
So I just need to install it,
…and then do a lot of clearing up.
There are a whole bunch of mono, bi and n-stables on this blog and they were mostly hyperlinked until some IT changes at EW disconnected them all. As I can’t face putting all the links back in the right places, here is a list instead.
A 74HC74 hysteresis mystery
Hysteresis mystery solved, probably
Two leds for one
And now the pcb
Simple circuit selects LEDs? – a tri-stable
More push button bistables
A 74HC4060 monostable?
Thoughts on another EEVblog – a power on-off bistable