As some of you might already know, the Hacklab has a photographic darkroom where we do processing of many kinds of B&W and colour films. All of these processes require a series of fairly precisely-timed steps, where the film or paper is exposed to various chemical baths. A number of these processes require complete darkness (no red safelight!), so you can’t have a timer that has a readable display. Commercial timers solve this by beeping once per second, so you know they’re still timing. As you can imagine, this gets very annoying after an hour or more of working in the dark!

I set out to design a new timer that would be less annoying and more functional. My original design goals were:
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