Archived posting to the Leica Users Group, 2001/01/08

[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]

Subject: [Leica] Enlarger timer
From: Martin Howard <howard.390@osu.edu>
Date: Mon, 08 Jan 2001 20:16:25 -0500

I want the world's simplest enlarger timer.  It would have four buttons:

  * one push-button, marked "+10"
  * one push-button, marked "+1"
  * one toggle switch, marked "focus -- expose"
  * one push-button, marked "start-stop"

Pressing the "+10" would increment the time by 10s, max 90s.  Pressing the
"+1" would increment the time by 1s, max 9s.  Toggling the switch to "focus"
the enlarger light would be switched on for focussing, while at the "expose"
setting it would be controlled by the timer.  Finally, the "start-stop"
button would start and stop the timer (switching the enlarger on and off as
it does).  If the timer was allowed to run it's course, it would
automatically stop at zero and shut off the enlarger.

If I had a soldering iron and more than three brain cells that understood
electronics, I'd build this out of a piece of bread board, a 555 timer
circuit (is that what they're called?) and four red, seven segment LEDs.
The whole thing would probably cost less than $20 to make, including the box
and be small and neat, rather than a big, heavy box like the analogue
Time-O-Lite or GraLab timers.

So, the questions is: has anyone already done this?  From what I've seen of
enlarger timers, they all cost $100+ which is just plain stupid for a 50c
timer IC and a relay switch.  Do timers exist in other fields?  Anything
designed for the photographic market seems to have a 100% markup (at least).

Any recommendations welcome!

M.

- -- 
Martin Howard                     | "Jesus loves you.  Everyone else
Visiting Scholar, CSEL, OSU       | thinks you're an asshole, but
email: howard.390@osu.edu         | Jesus loves you."   -- Bumper sticker
www: http://mvhoward.i.am/        +---------------------------------------

Replies: Reply from "Ken Iisaka" <ken@iisaka.org> (Re: [Leica] Enlarger timer)