I went through this a while ago and I was amazed nobody came up with
something that used one of those 5 cent clock chips you get in a
Being a pump and pulley guy I ended up with an intermatic timer (water
heater style) with cams "JB Welded" to the clock shaft.
Not pretty but EMF proof. ;-)
If you are suggesting interfacing to the "hours" seven-segment part of
the LCD display, that is relatively difficult. I did suggest using a
reflective optosensor together with a bit of reflective material on the
I'm sure there are other (possibly better) ways, but a PIC could do this
with well under 100uA of current and with way better accuracy than you need.
A pair of AAs should last roughly two years at 100uA draw.
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