DIY Enlarger Timer Circuit?
Years and years ago, I came across simple electronic schematics for making enlarger timers. I tried looking for these on the 'net, and found one type which is meant for timing exposures for making PCB "Exposure boxes". I don't know if this can be used as an enlarger timer. Anyone else got something different?
Buying a ready made timer may sound practical. However, almost all of the timers I see on eBay are for 110V, which is unsuitable for the 220V standard in use here. I am planning to equip timers for the 4 enlargers in the communal darkroom we recently set up.
Have a look on ebay in Australia and UK we use 220-240V
What grain............................................. ...............
Oh sorry, I forgot you don't shoot Large Format
Large format Pat.
All of Europe uses 220V.
Since you're in the market anyway, why not consider an f/stop timer?
Unless you really enjoy fumbling with circuit boards, integrated circuits, relays, etc. I suggest you buy a ready-made timer. Regarding the costs, you will find that building your own is much more expensive than you think. Displays, switches, buttons, knobs, cables, connectors, box, power supply, and things you don't imagine are the most significant parts of the cost, not so with the "fundamental" parts of the project (SSRs, ICs).
I second Ralph's suggestion of an f/stop timer, they are a lot more comfortable than a simple "seconds" timer.
Unless you have a special need (a function that isn't available in comercial timer) buying is much better than building. I have build many timers but it's never cost effective.
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There is a design for a simple, seconds only (no f-stop timing), timer on the Darkroom Automation web site.
The files are in the support section, towards the bottom of the page
(If you downloaded the files before 0:01 06April2010 download the updated schematic pdfs)
Last edited by Nicholas Lindan; 04-05-2010 at 11:09 PM. Click to view previous post history.
I'm with MPandolfo on this.
I actually do enjoy playing with circuit boards and stuff - and I have learned the following:
1. I only ever complete about 30% of all the DIY gadgets I start.
2. Only about half of those work as well as expected.
3. They always take at least twice as long to perfect as I expect, but sometimes ten times as long or more ^_^
So...I wouldn't go the DIY route unless you are doing it for fun and/or satisfaction or something. If you need working timers in a reasonable time frame - IMHO eBay is your best bet.
DIY F Stop Timer.
I am toying with the idea of a simple f stop timer. If there are those who are interested. I propose designing a simple DIY f stop timer which is open source around a simple pic chip.
Some of my thoughts are :
Simple to use
Always counts up from 0 to 64 seconds.
At start switch enlarger on.
Beep at each major f stop , e.g. 4 seconds 8s, 16 s 32s 64s.
Provison to beep also at 1/4 or 1/3 stops between major periods.
e.g. count up to 8 seconds and beep at each quarter stop.
ability to set range for beeps. - helps with making test strips.
at end of counting period trigger a rely to switch the enlarger off.
I can draw a picture of this simple device. But don't know where to post it.
The target price should be around $25 -$35.
Shoud use a simple 5V USB plug pack or 12 Volts plug pack.
1) Make up kits for those who want to solder them up
2) Make up finished items - small run of 50 units for those who don't wish to bother wiht the above.
3) Offer schematics and board layout to the APUG members and anyone on the web for that matter.
5) Wite up the software to control the timer- offer binary and source code to anyone.
6) Get a repository going for those who want to offer modified code based on the board layout.
I'll definitely go with SMD components onlyto minimise labour..
What do you guys think..
Do you need a simple F stop timer that beeps and lights a red led at each major F stop?
I'll definitely need one to help me wiht my test strips...
Please let me know your thoughts.
Isn't there some sort of cheap converter/transformer you could plug in to get the 110v timers to be useable at 220v?
“Do your work, then step back. The only path to serenity.” - Lao Tzu
The UK used to be 240 volts whilst the rest of Europe was 220 volts. All of Europe should now be standardised at 230 volts.
Originally Posted by RalphLambrecht