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(Arduino) automated macro-photography rail Answered

Hi everyone,

I would like to build an Arduino automated macro-photography rail (let's call it AAMR). I'm a decent software engineer and I want to learn electronics, so I'm looking for someone telling me I'm going in the right direction...

The idea sounds simple, I want to :
1/ place the subject on the AAMR
2/ input the # of pictures needed to perform a "focus stacking" (https://en.wikipedia.org/?title=Focus_stacking)
3/ push the start button and make the AAMR loop n times through the following steps :
- trigger the camera to take a picture of the subject
- move the subject 1 millimetre toward the camera

After a couple weeks reading and day-dreaming, here are my thoughts. I need :
- to
- a steeper motor and its driver (I own bipolar steppers and L298 / L293 IC)
- to trigger the camera (Canon EOS 70d : remote cable is quite easy to make)
- a potentiometer and 2* 7segment displays (input and display the # of pictures)
- a start button
- a reset button to make the rail come back at position Zero
- two "end of course" buttons (not sure about the English terminology), just in case the motor wants to jump over the board
- power (5v for the arduino and the logic, 12v for the motors)

I. Arduino
First things first, I plan to use an Arduino Uno during prototyping and replace it by a home made board in the final product.
Uno has 14 Digital I/O Pins and 6 Analog Input Pins :
- stepper => 6 Digital pins (3 ?? if using http://www.bristolwatch.com/L298N/L298N_arduino.htm)
- 7segment led => 3 Digital pins if using shift registers (https://www.instructables.com/id/Different-methods-of-driving-7-Segment-LED-display/step5/null/)
- start button => 1 Digital pin
- reset button => 1 Digital pin
- "end of course" buttons => 2 Digital pins
- camera trigger => 1 Digital pin (to drive an opto isolator / solid state relay)
- potentiometer => 1 Analog pin
14 Digital pins ! Uno should do the job, am I right ? (I know I could use Analog pins as Digital ones, but it seems I don't need it...)

Next interrogation is about power supply : I don't want a battery powered device and my options are scarce :
- ATX PSU supplies both 5 and 12v, but Arduino seems to like >5v, so ATX doesn't seem a good choice
- home made PSU from an existing wall wart -> voltage divider to get ~7v and ~14v -> 7805/7812 voltage regulator (may need heatsinks and/or little fan)

If I do the math :
- Arduino : 50ma
- Stepper motor : 700mA max
- L298 : 70mA (quiescent current)
- 2* 7Segment LED (multiplexed) : 2 * 80mA (estimated)
- Shift registers IC (SN74HC595N) : 1ma
(optional : Hex inverter 74LS04 : ?? mA)
Total : around 980mA... Am I doing right ?

I have tons of questions left (Hex inverter, filter capacitors, motor noise reduction, solid state relays...), but it's a good start :)
Sorry for the long post, and thanks in advance for your answers !



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5 years ago

You sound like you have it sorted. Was there even a question?

Depending if you can get away with just changing the focus on the camera and not needing to physically move it you could just command it.

Cameras, and yours in the above video, are capable of accepting more than just trigger shutter command. This may make it easier? Depends if you like software more.

An example of tool kit, not your camera:


interested to hear how you go.


Reply 5 years ago

Hi !

Thanks for your answer. Actually, I wanted to check with the community if something was wrong with my project... you answered that :)

I saw a couple sites about Canon HDK, but I'm really trying to build that thing instead of staying in my software comfort zone.

I'll try to write an instructable when done, but it may take time. Don't hesitate to message me if you really want to know how things are going.

Thanks again!