SDM - Stereo Data Maker

SDM is a version of CHDK (Canon Hackers Development Kit) designed specifically for syncing 2 or more Canon compact cameras for 3D photography. It also simplifies CHDK for single cameras and Kite Aerial Photography.

In a nutshell, it means a lot of the irrelevant CHDK stuff is gone leaving a much cleaner menu.

Just like CHDK you need to establish your firmware version, download the correct build, copy it onto a freshly formatted SD card, lock the card and you're in business.

Development of SDM seems to lag behind CHDK, probably because developers like David Sykes, another very clever KAPer - see this KAP forum post, need to get a hold of two identical cameras to test syncing function. It's not officially available for the Canon S100 yet but beta versions are easily obtainable. Ask nicely on the KAP forum.

Dave Mitchell's ACID and SDMinst apps are very helpful once again to get it all running.
UPDATE: and his new STICK and ASSIST apps are even easier to use.

The value of SDM and CHDK is the ability to run scripts. These are simple programs written in uBasic language. There are plenty of scripts pre-loaded with CHDK/SDM or you can download more from the KAP forum or CHDK/SDM websites.

uBasic is a very simple and easy to read language that can be edited in any text editing app like Notepad or TextEdit. I used TextWrangler on the Mac. The scripts must be saved as simple text files with the file extension .bas

WindWatcher and HQasem have shared some fancy scripts on the KAP forum.

My basic intervalometer script looks like this:
@title APN intervalometer
@param t interval(sec)
@default t 5

rem single camera, display off
sleep_for 1000
sync_off
turn_backlight_off
sleep_for 1000

rem endless loop with delay
while 1
shoot
sleep_for_seconds t
wend
end

If you want to use it copy the text, paste it into a text editor then save it as APNintvl.bas or whatever you want. Feel free to edit and personalise it to your own needs.

Copy the .bas file into the SCRIPT folder in the CHDK folder on your SD card and it will appear as a choice in the list of scripts.

Here's how SDM appears on the Canon S100 screen:

 Splash screen on startup. Wait for it to go before pushing any buttons.

 Push the Review or Play button to enter <ALT> mode. 

Currently selected script (APN intervalometer) is displayed along the bottom left.

 In <ALT> mode push MENU to bring up the SDM Basic menu

 Here's the Scripting screen where you can load a different script or change current script parameters

This is my intervalometer script set to shoot every 5 seconds. This script also blanks the screen while shooting which prolongs battery life.