DSLR power and shutter control with the Rajiva MCU Update/Littlefoot

So, everything is ready to run and you find that the battery is low on your DSLR and you didn't bring a spare. What's to do? Wouldn't it be nice to power your DSLR from a DC supply (auto or battery) and not worry about your battery running out in the middle of a set series of shots? Well, here is a small board you can make to eliminate the battery. In addition it allows you to control the shutter using the the Rajiva MCU Upgrade/Littlefoot from your computer using many software applications.

While simpler versions exist, I like to use opto-couplers where I can just to keep things apart. While the camera's ground and the mount's ground will end up together at least we can keep the shutter circuitry on it's own.

Parts List
  • 1 x LM317 linear voltage regulator
  • 2 x 1N4001 diodes
  • 1 x 220R 1/4W resistor
  • 1 x 1K2 1/4W resistor
  • 1 x 330R 1/4W resisotor
  • 1 x .01uF capacitor (ceramic etc.)
  • 1 x 470uF 16v capacitor
  • 1 x TO220 heatsink
  • 1 x BS250 P-channel FET
  • 1 x PC827 dual opto-isolator (or equivalent)
  • 1 sheet of copperclad
  • Some wire, solder etc.
Here's a small schematic to help you out:



And a drawing of the board and layout:

And a picture of my prototype board (slightly different but I'd do it differently now):



If you want to know how to build your own 'battery eliminator' go to this page.
If you don't have the Rajiva Upgrade... here's a board that might help.
For a Photoshop document with layers of the layout with a printable copper layer click here

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