The Darkroom timer came about after building my makeshift darkroom which you can read about in the previous blog post.

I realised I really need to have a darkroom timer. I made the Spinmatic project for developing film so I reckon I could use the same code or at least modify it.

Hence the birth of a new project. The same components as before with replacing the servo for a relay. This was the first step. However a red display is really required for any kind darkroom work. Of course the use of a red filter over the OLED display would be a solution.

So developing code or a project for that matter, the MVP (minimum viable product) approach might prove best. I’ve learnt for my professional life this method which could applied to my private project quite nicely. Especially when time is limited when family and friends are also a priority too. Let’s begin the first idea…

Basic OLED and WeMOS Timer – First version

Source Code :

The same hardware as the spinmatic just with a relay in place of the servo.

Video/Picture to follow

add the relay shield and it’s done.

LED Matrix and WeMOS Timer – Second prototype

This is more elaborate involving the right pins on the WeMOS to link up to the LED Matrix. The rotary encoder needs to be re-pins so that SPI interface on the ESP chip is available for the LED Matrix.

Source Code:

LED Matrix – Enclosure for Darkroom Timer

I required a enclosure for the LED Matrix and WeMOS which I can print on my tiny Ender 2 3D printer. So I rotated the model diagonal too see if it would work.

3D Print Enclosure for Darkroom Timer

3D Print Enclosure for Darkroom Timer

Unfortunately the 3D print was still too large for my build area on Ender 2 3D printer, I resorted back to old school methods.

Back To Old School – Version 3

Finding a enclosure box in my basement from when we hadn’t got the likes of 3D printers and such, I drew out the layout of wiring and boards for the Darkroom Timer – version 3!

While at the electronic shop I came across extra pieces which I thought would be cool for the project. This always seems to happen when go shopping for parts. Hence the additional foot switch in yellow!

Electrical Wiring Up

After cutting and pulling out slots made in the side walls of the box with a pliers I had most of the electrical components installed.

Below is a one to one sketch I made by tracing around the parts to get the layout right.

Part list for Electrical parts

I also made an hole for the headphone socket which is to be used with the yellow foot switch. But more about that later.

Everything need some hot glue and protection.

Big Warning!

Don’t mess about with main electricity unless you know what you doing. These voltages can kill you, take proper care to ensure to protect yourself. I’m not responsible for anything this project will do or won’t. Main outlet current can kill. Ok that should be enough. /Warning

More to follow!

Other Darkroom Projects

February 28, 2019

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