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Modifying a Canon DIGITAL IXUS v2 for external shutter release

Details

Canon DIGITAL IXUS v2For a KAP project I'm working on I need to be able to control a compact camera with an Arduino processor. Because I didn't want to risk damaging one of my 'good' compacts, I bought a second hand Canon DIGITAL IXUS v2 for just €15,- (including the battery charger and a 16 MB CF card). This camera is known as  Canon S200 DIGITAL ELPH, in some parts of the world.

Initially I didn't feel much like modding the camera itself: the scale of integration inside that body is so large that I was afraid to break it while working on it. So I went with mechanical solution: I made a bracket on top of the aluminium frame that holds the camera, and mounted a mini servo onto it. The servo horn I modified with a piece of plastic from an old toothbrush (see photo at the end of this article).

This would have worked, if it wasn't for the fact that the frame construction wasn't stiff enough: while pressing the shutter button, reaction forces pushed the servo upwards and away from the shutter. Using ty wraps and a piece of metal wire stabilized it a little bit, but it was not a satisfying solution.

So I decided to take the plunge and try wiring the shutter release instead. This turned out to work well, and is not too hard to do.

What you need

For this mod I used the following tools and consumables:

  • small phillips screwdriver
  • small straight screwdriver
  • soldering iron with a fine tip, solder
  • 20 centimeters of CAT5 or phone cable
  • pen, paper, Scotch tape, hot glue, thin piece of plastic or rubber

Prepare

A lot of small screws hold the camera together, and they are of differing sizes. To keep track of the location of each screw, I sketched a diagram of the camera on a sheet of paper. I would then stick each screw to this diagram with a piece of Scotch tape, as soon as I had removed it.

Remove the outer insulation from the CAT5/phone cable, so that you get the individual wires. The thinner the wires the better, really, so if you have thinner wires you'd better use those.

Open the camera

  1. Remove the battery and the CF card.
  2. Remove all screws and stick them to the diagram in their appropriate places.
  3. The camera cover consists of two cover: a front cover and a rear cover.
    1. Carefully start pulling the rear cover away from the front cover.
    2. You may find that the display is stuck to the rear cover. If you apply a little pressure to the display it should come loose.
    3. The CF card cover will probably come loose, as will the AV Out (rubber) cover. Don't loose the spring and shaft from the CF card cover.
    4. Carefully pull the front cover away from the body. Take care not to apply pressure to the lens assembly.
    5. Set all removed components aside.
  4. Remove the screw that locks the shutter assembly (photo below, circled).
  5. Remove the shutter assembly (it has a small latch on the right side of the camera, use a little pressure and/or the small straight screwdriver to unlatch it). photo of shutter assembly

Modify the shutter switch

The shutter has two positions (three, including the 'released' position): half depressed, at which the camera focuses, and fully depressed, where the picture is taken. The electrical shutter switch is exposed when the mechanical shutter assembly is removed (below).

  • When the switch is half depressed, a circuit is completed between contacts (A) and (C).
  • When the switch is fully depressed, a circuit is completed between contacts (A) and (B).

Using a soldering iron with a small tip, solder three wires to (A), (B) and (C). I used black for common, green for half depressed and red for fully depressed.

shutter contacts wires soldered to shutter contacts

The wires have to be routed outside the camera, but there's very little space to route them. After contemplating drilling holes in the housing and hacking away at the ocular/prism assembly, I decided to bring the wires out through the holes of the shutter assembly.

  1. Turn over the shutter assembly.
  2. Remove the three screws that lock the shutter, the on/off button and the electrical contacts for the zoom mechanism.
  3. Remove the zoom contacts.
  4. Push the shutter button out of the assembly.
  5. Replace the on/off switch and fasten it with the silver coloured screw.
  6. Screw the removed parts of the assembly back together so that parts don't get lost. You may want to reserve the mod in future.

The steps above remove the zoom mechanism, which means that from now on the camera will only operate with the lens at the shortest focal length. I can live with that, but if you want to be able to operate the zoom mechanism as well, you'll have to solder a couple of wires to the zoom contact strips on the PCB (to the left of the shutter button, in the

Close the camera

  1. Lead the three wires through the holes in the shutter assembly and fit the shutter assembly to the camera with the one screw.
  2. Place a little piece of plastic or rubber over the shutter button and the soldering points, so that, when the covers are closed, the PCB is not visible through the holes in the cover (like they are in the picture, right).
  3. Fit the rear cover, including the hinge for the CF card cover and the rubber cover for the AV Out connector. Make sure that the plastic switch cover for photo/movie/preview is interlocking with the switch itself.
  4. Fit the front cover.
  5. Fasten all screws in their proper location.
  6. Replace the battery and the CF card.

Test your modification

  1. Switch on the camera.
  2. Hold the black and green wire together: the camera should focus.
  3. Hold the black, green and red wire together: the camera should take a picture.

Finishing touch

When you know that everything works it's time for the finishing touch: make the mod more robust and seal the holes in the camera so that no dust, moist etcetera can enter it.

I bundled the wires with pieces of heat shrink tubing and tied them to the metal eye that's there for the wrist strap. Then I took the hot glue gun and applied some glue to the shutter area, both to hold the wires firmly in place and to prevent dirt from entering the camera.

mod complete

Alternative

If you don't feel like messing around with the insides of a compact camera (and I don't blame you), you could try my original attempt at a mechanical solution (see photo to the right). However, you have to make sure that the material you use for the bracket/frame is stiff enough to prevent bending when the shutter is pressed. Aluminium sheet of 1.5 mm is definitely not stiff enough.

   
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