Spinmatic! - Automated Film Development

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Introduction: Spinmatic! - Automated Film Development

About: Black and White Artist Photographer, who loves the great outdoors and adventures.

It is true though, as much as I love film and development, twisting a spindle for 11 minutes or 20 minutes seems a complete waste of anyone's time. This is where the 'Spinmatic' comes to save the day, so you can have perfect timely development and rest after a long days shoot!

This article was first posted on my blog : http://i386.com/2018/04/spinmatic-automated-film-development/


The Story

Awhile back I saw this idea from another photographer Lilly Schwartz . I thought that it was a really clever piece of trickery. It must have been about a year ago I first saw her write up and instructions. So a few weeks ago I managed to have some precious time to purchase, build and learn a bit about 3D printing. I really thought 3D printing would be difficult but to be honest it's not. In fact it's so much fun to the point of addiction nearly. I just wish I had such technology to hand when I was fourteen years old, but maybe maturity has at least kept me in some ways focused. Lilly's design had stayed in my head and I thought would it be great to take it to the next step ?

I had christened my Automator project, the 'Spinmatic' and why not! It involves the knowledge of not only photography but four very different arts combined. This is what makes 3D printing so exciting right now. For example, you are into some hobby, you search for models relating to your hobby on Thingiverse and start making. Then you even make you own idea into reality and then share it. How great is that!

So I had the basics at hand in each of the four fields - electronics, 3D printing, programming and film photography. I had started developing my own black white film at home for the past couple of years. While doing this I had required a reawakening of electronics from my work colleagues who explained the Arduino and ESP8266 microcontrollers. Now my passion in these fours areas could be brought together to make something amazing or at least useful! Hence why the 'Spinmatic' was developed (sure, no pun intended).

Step 1: Building the Spindle and Base

I had jotted down a couple of ideas. Made a first prototype, then a second and so on. Until version five came alive. The reincarnation of the spindle - Yes! The top of the spindle now has a neat way to hold the servo's lever, the white little piece that attaches to the geared motor. I had tried previously to attach the spindle directly to the servo but this proved too rigid and problematic. The spindle thingy when you turn it manually goes up and down due to the inner column's curved base inside the tank. The original spindle was measured and the duplicated designed in Tinkercad. After fives prints and modifications I had a working charm. The part now has plenty of freedom to move up, down and a bit left and right too. Also it's easy to fit the part to the servo too, through the side openings. The end of the part prevents it from falling off the servo too - that's my favourite piece of engineering of the spindle.


The 3D Prints can be downloaded from Thingiverse https://www.thingiverse.com/thing:2857145 Note the spindle requires a 'raft' when printing. The raft gives support while printing narrow and upwards. The base is a simple polygon shape with a cut out for the 5V servo. Once the 3D Print is made, then the electronic circuit is required.

Step 2: The Circuit

The circuit is straightforward. The transistor is required to drive the mini speaker as the ESP8266's output would be too weak. This output is from the D4 pin where also the on board LED is too. The LED will blink when the development time has reached an end. Please note: the speaker will make some clicking noises while updating the firmware - it's a feature not a bug! The servo's signal pin is attached to D8 and supplied with 5 volts. The OLED Display requires just 3.3V from the ESP's 3.3V pin. The OLED operates in I2C mode, using D1 and D2. Electronics

Part List

  • 10kResistor
  • NPN Transistor
  • Mini Speaker
  • WeMOS
  • ESP8266
  • SDS1306 OLED Display
  • Servo 5V

Step 3: The Code

Let's talk about the code. Basically the project started with the demo code for sweeping the servo back and forth. Once I got this to work, I added the sounds or tones. Some tones on start up and when the timer had finished.

The timing is the most important part of the project. For this I used some sample code from https://playground.arduino.cc/Main/CountDownTimer... Normally sample code has delays this would affect the over all development time. So the 'CountdownTimer' has really needed. Once the timer was working, I added intervals for the rotations for back and forth. Of additional coding could be added to make more turns. I've left code functions inside for future developments.

Download the code

Step 4: Final Note

The next step would of course be to make the 3D design for the lid to hold the microcontroller and OLED display. After that I'd add a rotary switch to allow adjusting the time and intervals on start up.

What would be really cool would be to utilise the wireless module to connect to the Internet to allow notification to your smartphone. But that's not all, how about an automatic mode ? Let's say you connect to the massive dev film chart via the rotary switch and display the film selection and ISO, this would set the overall development time... Yes certainly more possibilities. Feel free to add your ideas and let me know!

This article was first posted on my blog : http://i386.com/2018/04/spinmatic-automated-film-development/

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