I also have one of these timers and am interested. Being a retired analog
circuits guy I've also designed a replacement, but using analog circuitry,
just for fun. I figure I'll build it over the summer. The cost will
certainly be higher than your approach, but I wanted to do it this way just
because.
Please keep us posted.
On Fri, Mar 23, 2018 at 12:42 PM, Tim Daneliuk <tundra@xxxxxxxxxxxxxx>
wrote:
I know some of you here are engineers and may be interested in this ...
I have a Zone VI compensating development timer which I use regularly
and happily. However, with the company now long gone, the "lifetime"
warranty is not of much good :) Moreover, it was an analog device
with essentially only 2 compensating curves.
"So", sez me, "I are an engineer, I can design one" ... and that's what
I've set out to do. The idea is to use modern, cheap digital hardware
and keep multiple correction curves in a table for any developer/film
or developer/paper you wish. Such tables would be kept permanently
encoded in the program firmware and some mechanism (tbd) would be
used to select which one you want.
The current approach involves a Raspberry Pi Zero ($5),
with a $0.99 red LED display array, a $4 temperature probe, and code
in Python (maybe ... I may need to switch to C or Go). Total cost
with SD card and power supply/cable looks to be around $20-30 including
case and footswitch.
If anyone else has interest in such a thing, let me know and I will update
here if/as I make any progress. If not ... I just shut up already ...
--
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----------------
Tim Daneliuk tundra@xxxxxxxxxxxxxx
PGP Key: http://www.tundraware.com/PGP/
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