Before starting these modifications you need to understand that the camera can no longer be used as a normal camera. The shutter button will be removed and there will be wires coming out of the camera. You are modifying it so a computer controls the shutter thus controlling when it takes pictures. If you do not want to modify the camera then you should use a servo to activate the shutter button as I did in my earlier flights.

Procedure
1. Remove the batteries and memory, if installed.
2. Remove the 6 small Phillips screws. One of them is under the A/V cap.
3. Gently pry apart the two halves starting from the bottom. You will notice that the lanyard side of the camera does not want to come apart. Use a small flat screwdriver to pry apart that side of the camera where the lanyard meets the camera body. The top part of the camera snaps in place so be careful when pulling the two halves apart.
4. Looking at the back of camera you will notice the flash capacitor on the left side. Be careful, it will SHOCK you, so stay clear of that end.
5. On the right side you will notice the surface mount switch at that top. This is the switch you want to tap into. You can either solder directly to the pads with the switch in place or you can remove the switch completely. Your choice. I removed the switch by prying it up. It does not take much force since it is surface mounted. Then I used pliers to pull off the switch contacts which exposed the pads.
6. In either case, you will need to solder across the front two pads and back right pad with a different color 24 - 30 gauge wire as shown in the diagram below. The length of the wire is up to you but I would suggest at least 12 inches. It really depends on how far away the micro-computer will be from the camera. I enlarged the switch pads in my diagram to show you detail but in actuality they are tiny. The front two pads are for focus and triggering the camera. The back right pad is the ground. Be careful when soldering to the back right pad because there is a surface mount resistor next to it and you do not want to burn it up from excess heat or accidently unsolder it.

Before reassembling the camera body you will need to modify the shutter button to allow for the wires. You can reuse the button cap if you are careful. Figure A shows what the top looks like before the modifications.

7. Flip the top over and you will see 4 catches that hold the shutter button cap in place. Carefully push in the catches and the button will pop off. You will not need the spring.
8. Once the button cap is removed it should look like figure B. You will need to remove the excess plastic that I have shown in dotted lines. An exacto knife will work the best.

9. Clean up the edges so the wires will not get chaffed. After removing the excess plastic turn it over again and it should look like figure C.

10. Reassemble the case. Run the wires through the shutter button hole prior to reassembling the case. The case should just snap back together. Start from the top and work your way down.
11. Replace the six screws.
12. Install the batteries.
13. Turn the camera on.

You should be able to take a picture by shorting the two wires together for ~1 sec. If not you will need to recheck your wire connections to make sure you did not knock them loose while assembling the case.

If you can take a picture and the shutter cap is still usable you will need to cut out a hole in the cap for the wires as shown in the figure below. You might need to break one of the catches off the cap depending on the wire gauge you used.

Replace the shutter cap. If it will not stay by itself then you can use super glue or tape to keep in place.

The final modifications should look similar to the below picture

You can see from the schematic that the transistor switch is very easy to make and it can be part of your overall motherboard design or a separate PCB. I will be incorporating it into a seperate PCB design so that I can reuse my existing motherboard.

The theory of operation is that the collector and emitter act as a normally open switch until the base has voltage applied. Once the base is biased by putting the I/O pin high, current will flow from the base to emitter allowing collector-emitter current to flow which triggers the camera.

The code sniplet I have provided is based on the STAMP and the Propeller micro-controllers. I have assigned a name to PIN 7 to make it easier to read. Two second delay works best with this camera and you can not take another picture until it has finished writing it to memory so give yourself about 5 second between shots. I have used 4 Gig SD cards with this camera.