Here is my memo: How I make camera launcher from old servo electronics, usb-cable and diode.
Here are quite many steps, so I write this memo if I need to make system again... Programming took only few minutes, to build circuit took more time.
My camera is Canon PowerShot S90
- Buy max 4 Gb memory card to camera.
- Create a file to memory card, name it to ver.req (last letter is small Q) Content can be anything.
- Put memory card into camera. Go to Play mode. Press FuncSet -button down and in the same time press Disp-button.
- Look Firmware ver number.
- Go to page http://mighty-hoernsche.de/ and search the right version to camera model and version. Select Full version
- Unzip files to memory card root
- Put memory card to camera. Turn camera on, go to Play mode
- Press Menu, search Firmware Update. When camera says Update firmware, answer Ok. Camera starts to CHDK Play mode
- Press Print button [S], to bottom of screen comes <alt>, then press Menu. Select Miscellaneous stuff, and Make card bootable. Press FuncSet, nothing seems to happen, but everything is ok.
- Go to previous menu and select Scripting parameters / Load script from file. Search and select REMOTE.BAS
- Remote Parameters / Enable Remote [o]
- Select Scripting Autostart [On] and Save params [o]
- Switch camera off, and take take memory card off. Put small Lock switch in memory card to Lock position. Put memory card to camera.
- Start camera. Camera starts to Play mode, and now in the lower left corner should read ***Autostart***
- Make the camera launch circuit from old digital servo electronics, diode and Micro-USB-cable. Remove motor and put diode and cable to its place. Check that during launch there should come 5V to red wire and GND to black wire. When launch is not on, there should be 0V between wires, never negative voltage!
- Test with camera. I have used channel 5 from receiver, then I can turn camera on with Gear switch. If switch is on, camera takes pictures at 2 - 3 seconds intervals.
- If I use camera to other purposes, I just turn Lock button in memory card to Off position.
- It is also possible to remove the potentiometer, and make voltage divider from two resistors.
More details http://chdk.wikia.com/wiki/CHDK
This same page in Finnish