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DIY S5 IS Remote Shutter
, Latest Aa Electronics News
Image by Roger Smith
More and more owners of Canon PowerShot cameras have found CHDK, which is a firmware hack that allows users to add a lot of additional capabilities to their cameras. The capabilities include faster and slower shutter speeds, addition of RAW format, increased aperture range, better histograms, battery monitors, and user control scripts. I’m not going to discuss how to install CHDK or any scripts here. The links in these instructions (and the discussions in the Canon PowerShot S5 IS Group provide lots on good information on how to do that.)

UPDATE: (31 August 2008) The newer Juciphox Build of CHDK allows for the remote to work without additional scripts. In my initial testing, this version is much simpler to use than the older script-based technique.

One of the scripts available to CHDK users adds the capability to remotely trip the shutter using the camera’s USB port. Before you read any further, please note that while most things that you can do with CHDK cannot harm your camera, applying too much power to the USB port on your camera can cause major damage that Canon will charge you an enormous amount of money to repair. This is a fairly easy hack if you own a multimeter and a soldering iron, but if the thought of wiring a homemade device into your beautiful little camera and risking the possibility of causing it go KABLOOEY makes you feel uneasy, then this may not be the project for you. IF YOU FOLLOW THESE INSTRUCTIONS, YOU DO SO AT YOUR OWN RISK.

There are some great webpages that explain the process of building and using a USB remote trigger, including the script itself. Since a remote trigger is great for long exposure and macro photography, I decided to build it for myself. I followed the instructions, but it didn’t work. I could trip the shutter by running the script and connecting the camera to a laptop via the USB cable, but not when my trigger was connected. I tested and retested it, but nothing would make it work. Finally, I found this page that indicated that unlike the S2 IS and S3 IS, the S5 needs at least 3.7V to trigger instead of the 3V that would trigger the earlier cameras. So, I rebuilt the remote to use 4.5V (using a 3V CR2032 watch battery and a 1.5V "Type N" alkyline battery) , and it immediately worked like a charm.

I bought all of the components at Radio Shack (and the part numbers listed below are their part numbers, this isn’t an add for them, they are just the only place in my small town that sells this type of stuff). The case is a 270-1801 Project Enclosure (.29), which is 3x2x1 inches (7.5x5x2.5 cm). The momentary push button switch is part number 275-646 (.49). It is mounted in the case with a 1/2 inch hole. I also routed out a small hole with a Dremmel tool on a corner opposite the switch so that the USB cable could exit the case once the lid is screwed back on.

I cut a spare USB extension cable with "Type A" ends (i.e., with a plug on one end and a receptacle on the other). I stripped back part of the cable on the receptacle end and found the wires corresponding to pins 1 and 4 using a multimeter.

To generate enough power in such a small enclosure, I ended up using both a 3V CR2032 battery and a 1.5V "N" alkaline battery. The battery holders for these are part numbers 270-0009 for the CR2032 (.99), and 270-405A for the N battery (.99). I soldered the black wire from the N battery holder to the "+" connector post on the CR2032 holder. I then soldered the red wire from the N battery holder to one post of the switch. I then soldered another length of red wire to the other post of the switch, and a length of black wire to the "-" post of the CR2032 holder.

I attached all of the battery holders to the inside of the case using double-sided tape.
FInally, I soldered the red wire from the switch and the black wire from the CR2032 enclosure to the wires corresponding to pins 1 and 4 respectively on the USB receptacle cable that I cut earlier. I then taped up these soldered connections with electrical tape and packed them into the case as neatly as I could. After screwing the cover back on, I tested the switch with a multimeter to verify that pins 1 and 4 of the USB receptacle showed approximately 4.5V (but under no circumstances more than 5V !) when the button was depressed.

Once this was done, I connected it to my camera with a Type A to Mini-B USB cable, turned on the camera, started the remote shutter CHDK script, and my new remote worked perfectly!

I chose to use a Type A receptacle with a short cable on my remote. Some may prefer wiring a Mini-B type plug directly, but this method provides me with more flexibility. The short cord makes it easier to carry and store, and allows me to connect a short USB cable (which I carry in my bag), or a long one (which I don’t) depending on what I’m going to do. It’s also a lot easier to test the contraption during construction with the larger end than it would have been with the Mini-B.

I built this remote for about .75 (plus about for the batteries!). I was also able to use a USB cable that I already had. Local businesses were all really proud of their USB cables, but they can be purchased pretty inexpensively on the web.

Finally, if you don’t want to use an "N" battery, any 1.5V battery will work. AA or AAA batteries would work fine, but I didn’t have room in my case to use them.

UPDATE (15 September 2008): I have now built a second trigger with a larger case that uses three AAA batteries and that has a larger button for use by people with limited manual dexterity.

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