DIY digital enlarger timer!

[Jadedoto]

so i am a bit of a geek and needed a new enlarger timer...

i wanted a nice digital one, but those are pricey even used, so i made my own. basically it is an arduino and a relay, power supply and a cut up extension cord... i have been planning it for a few weeks, and took me about five hours to slam together tonight and it works like a charm

Dead Link Removed has all the pics, schematics and code if you are interested. whaddaya think?

it is programmed to either count up or down, in half second increments... with a focus button. of course, since it is software, i can change the time increments, but for me half a second is plenty good resolution....

 

[heespharm]

Could you make a small one that's attached to a piston that can actuate a shutter release cable to use for timed exposure... E.g. You set the time and an electric piston pushes the shutter release cable and keeps it depressed for 2hrs or however you want your exposure to be... Now that would be cool!!!

 

[Jadedoto]

well, the device does run on a 9v battery and there are smaller versions... it would be trivial to modify to that with a servo... but for another day, my friend

however, if you would like to, i would love to see it!

 

[John Koehrer]

Could you make a small one that's attached to a piston that can actuate a shutter release cable to use for timed exposure... E.g. You set the time and an electric piston pushes the shutter release cable and keeps it depressed for 2hrs or however you want your exposure to be... Now that would be cool!!!

#2 here, say from 1/30 to ~5 seconds.
I looked the programming, iepened, said ? and closed it. Geez.
Ever see someting similar in a kit or semi kit?

 

[tkamiya]

VERY nice.... You might want to write up an article and put it in APUG as blog or something. Every few weeks, someone asks about DIYing timers here. Just one suggestion... you might want to add a diode across the coil of the relay to protect the driving transistor from transient voltage.

 

[Anthony J. Martinez]

This is pretty cool. I broke the timer that came with my CB7 (or rather it was electrically broken, and I've not physically broken it). I dare say I may have to go ahead and make one of these. Thanks for posting!

 

[BetterSense]

I think you meant 1.5A/120V relay.

I would consider making it work in f/stop increments rather than linear increments.

Also, I would cram a PSU in that box so I didn't need a 9V battery.

 

[Anthony J. Martinez]

Could certainly be programmed that way. I may or may not do that when I build mine. Haven't decided yet. Need to keep doing diff eq until my brain explodes so I can't possibly screw it up on a final I have coming up.

 

[Dave Mueller]

I built one from a Parallax Basic Stamp a while ago. Worked pretty well, I could switch between F-stop timing and .1S increments. Never made it into a box before I had to take the darkroom down :-(

 

[Ralph Javins]

Good morning, Vincent;

I did something like this back in the 1970's using all 7400 series TTL logic packages, and the rectified pulses off the power supply as a source of clock pulses. Setting the time was done by turning rotary switches to the desired indicated time. Then a push-button started it running. I think your method takes fewer parts than mine did, but then, at that time, the Intel 4004 was out, and the 8008 was just about to appear. And, there was no "programming;" it was all hardwired logic. When I left, the box was still working, but I do not know if anyone still there really knew what it did.

 

[Jadedoto]

I consided doing it in discrete components... But this was the faster method. That is pretty cool-- but tell me you did it in vaccuum tubes amd I will be really impressed.

 

[Anthony J. Martinez]

Tomorrow, after I finish my diff eq final I'm off to attempt local sources for the components for a weekend build. Thank you, Vincent, for posting this.

 

[shawny2005]

thats sweet!

 

[Anthony J. Martinez]

Happy to report that this works like a charm, and to thank Vincent for some help on twitter.