Control multiple cameras with a single button using the attached program at the end of this document. This solution will put the remote camera(s) button on steroids.
Stereo Data Maker (SDM) is an extension of CHDK which allows us to take images from multiple cameras that maybe synchronized, auto interval time laps, and many more possibilities. I first encountered SDM when I was looking for a DIY book scanning solution using cameras.
By utilizing SDM, cameras can be connected to a non-powered USB hub. Sending 4.5 volts (three AA batteries) to the hub will activate all cameras at the same time. Connecting a switch between 4.5 volt source and the USB hub allows us to remote control multiple cameras. The first click of your remote switch will focus the cameras, and the second click will capture the images. Alternatively, you can hold the remote button a little bit longer (say about half a second), so that all cameras will focus and then capture their corresponding images (with a single long click).
With my newly built book scanner, I captured an 800 page book within 50 minutes. After that experience, I felt that there was room for improvement of the "remote" button's behavior. For example, because the last pages of of most book chapters have little content, the cameras are unable to focus properly. At times, both cameras may not capture because we relased the "remote" button too early.
To answer the above issues, and obtain more functions from a single button, I wrote a program for the SDM firmware. This program, when executed on the supported camera(s), offers the following capabilities:
- If the camera(s) is unable to focus on the image, it will use it’s last focus for the capture.
- You can disable the above “refocus” on bad focus option.
- With a single (a) Quick click, the cameras will focus and then capture the image, or with (b) Long hold click the cameras will capture the image without refocus.
- You can reverse your preferred behavior for the above single click. That is, single quick click can capture without refocus, and single long click will focus and then capture the image.
- Double click will refocus the first camera, triple click will refocus the second camera, and so on.
- If the first click is long, and all the remaining clicks are quick, then the camera refocuses and shoots to capture the image. For example: 1 Long and 1 Quick click will capture a focused image from the first camera. 1 Long and 2 Quick clicks will capture a focused image from the second camera, and so on.
- If all clicks are quick, and only the last click is long, then the image is captured from the corresponding camera without refocusing. For example: 1 Quick and 1 Long click will capture from second camera without a refocus. 2 Quick and 1 Long click will capture from the third camera without a refocus, and so on.
- If all clicks are long clicks, then the last image from the corresponding camera will be erased. For example: Double long clicks will erase the last image from the first camera, triple long clicks will erase the last image from the second camera, and so on.
- For the erase setting you can: disable it; specify to auto erase last image on all long clicks; prompt before deletion (single click to confirm; otherwise, return to capture mode).
- You can disable the multi-click ability.
- You can specify your default parameters (white balance, aperture, etc) so that next time the program is run, all your preferences are set for the capture.
- You can specify your threshold for how long constitutes a “long click”
- You can specify how many clicks a camera should respond to.
- Caveat – the camera unit is not a full blown computer; therefore, don’t expect to double/tripple click as fast as a computer mouse. Your clicks need to be a little longer than computer clicks.
Tested on Canon PowerShot A590IS
To use this program
- You will need at least SDM 1.80 for the supported cameras. Here is video instruction.
- You need to copy this program on to your camera’s SD-Card.
It is probably best to copy it into /CHDK/SCRIPTS/ folder.
- Enter you Camera’s Alternate mode. This is typically done by pressing the print button. When in Alternate mode, you will see ALT in the bottom of the screen.
- Within ALT mode, press Menu button to activate SDM menu.
- Navigate to “Scripting…” and the click the “Set” button
- Select load script from file
- Scroll down to adjust preferred settings. For example, each camera can be set to respond to a specific number of clicks (i.e. set left camera to 2, and right camera to 3).
- Exit back to ALT mode
- You should see “Edvin’s USB snap” in the bottom of the screen
- Press the camera shutter button (shoot) one time to start the program
You should see “Remote Capture Ready"
Each camera can be set so that a sequence of clicks will activate a particular camera. In below instructions, a dot will denote a short click, and a dash will denote a long click.
. A single short click will focus and then capture
_ A single long click will capture the image without refocusing. (To reverse this single shoot default behavior, change the first parameter value from 1 to 2).
. . Multiple short clicks will refocus the corresponding camera. for example, two short clicks may activate the first camera, and three short clicks will activate your second camera, and do on.
_ . If only ths first click is a long click in a multi-click capture, then the corresponding camera will focus and capture the image
. _ If only the last click is a long click in a multi-click capture, then the corresponding camera will capture an image without refocusing
_ _ If all the clicks are long clicks, then the last image from the corresponding camera will be erased
Any other button sequences will be ignored.
Below is a list of possible script parameter values:
a) Snap 1=FC,C 2=C,FC
Value 1 will cause the camera to Focus and then Capture the image on a quick click; and on a long click the camera will capture the image with out refocus.
Value 2 will reverse the above behavior for a single quick/long click
b) Long Press (.1 x Sec)
How long constitutes a long button press. Default is half a second.
c) Camera Specific clicks >=2
Number of clicks to invoke only this camera
d) White Balance Mode
-1=Your Manual setting, 0=Auto, 1=Day Light, 2=Cloudy, 3=Tungsten, 4=Fluorescent, 5=Fluorescent H, 7=Custom
e) Shutter Speed
-13=Your Manual setting, -12=15", -11=13", -10=10", -9=8", -8=6", -7=5", -6=4", -5=3"2, -4=2"5, -3=2", -2=1"6, -1=1"3, 0=1"", 1=0"8, 2=0"6, 3=0"5, 4=0"4, 5=0"3, 6=1/4, 7=1/5, 8=1/6, 9=1/8, 10=1/10, 11=1/13, 12=1/15, 13=1/20, 14=1/25, 15=1/30, 16=1/40, 17=1/50, 18=1/60, 19=1/80, 20=1/100, 21=1/125, 22=1/160, 23=1/200, 24=1/250, 25=1/320, 26=1/400, 27=1/500, 28=1/640, 29=1/800, 30=1/1000, 31=1/1250, 32=1/1600, 33=1/2000, 34=1/2500, 35=1/3200(s-series)
8=Your Manual setting, 9=F/2.7, 10=F/3.2, 11=F/3.5, 12=F/4.0, 13=F/4.5, 14=F/5.0, 15=F/5.6, 16=F/6.3, 17=F/7.1, 18=F/8.0
g) Image Quality
-1=Your Manual setting, 0=Superfine, 1=Fine, 2=Normal
S3IS: -1=Your Manual setting, 0=L, 1=M1, 2=M2, 4=S, 8=W
You may need to consult http://chdk.wikia.com/wiki/PropertyCase
-1=Your Manual setting, 0=AutoIso, 1=50(80), 2=100, 3=200, 4=400, 5=800, -1=HiIso
You may need to consult http://chdk.wikia.com/wiki/PropertyCase
k) Revert Bad Focus
1=Use previous focus if camera fails to focus; 0=Do NOT use previous focus if camera fails to focus
l) Enable Multi-Click
Enable multi-click. 1=yes, 0=no
This option requires the (L) multi-click option enabled.
0=Disable erase; 1=Delete last image from corresponding camera; 2=Confirm deletion of previous image by a single click
- After the camera goes into standby, the program is unable to complete the sequence of events invoked by the remote button. As a result, the camera freezes and it requires a restart (off/on).
You can work around this limitation by preventing the camera scree from turning off. To do so, you must change the "Display LCD off" setting to "Script" within the Alternate Mode. When your in ALT mode, click the menu button and then navigate to: Advanced Menu->Miscellaneous->Display LCD off" , and change the value from ALT to "Script".