DIY Shutter Release Cable For Canon Cameras with CHDK

April 29, 2012

If you don’t want to pay for an expensive shutter release cable, and are lucky enough to own a Canon camera supported by the CHDK hacked firmware, you can make your own for as little as one pound.  Click on the link to see how.

To make this cable there are a few prerequisites.  Firstly you will need a Canon camera with the CHDK firmware loaded on a memory card.  There are many tutorials available to help you do this – Google is your friend.

You will also need to be comfortable using a soldering iron, and cutting up and rewiring a USB cable.  If this sounds like you then go out now and grab the following parts from your nearest Maplin/Radio Shack/Friendly Geek:

1: A simple push button and a 5V battery.

The button can be any kind of on/off switch you want really, but I chose a nice big red button.  The battery however *MUST* be 5V, or 6V at a push.  If you can’t find a 5V battery then you can use two 2.5V or 3V batteries wired in series.  *DON’T* use anything bigger than a 6V or you run the risk of frying your camera.  Lower than 5V just won’t provide enough power to work.

2: Some kind of container to put your nice big red button in.

This can be as big or as small as you want really, but bear in mind you will need to drill holes in it, so the thinner the material the easier this will be.

3: An old mini USB cable that you don’t mind cutting into pieces.

I used the one that came with my camera since my computer has a memory card slot that makes the cable redundant.

Now, if you have all of these parts and the necessary soldering skills you are ready to begin.

First step is to drill the holes in your container tin.  This step is immeasurably easier if you have a drill, but if you don’t you can always do what I did, and spend 30 minutes hacking away at it with a penknife or similar.

The top hole should be the size of your button.

And the bottom hole should be the size of your cable.

The next step is to cut the end off your USB cable (the end that *DOESN’T* plug into your camera!)

You should see 4 wires, but we are only interested in the red and the black one, so go ahead and cut the others off and tidy it all up a bit.  If your cable doesn’t have a red and a black wire you will have to figure out which of the wires in your cable correspond to the red and black ones and use those instead – this is left as an exercise for the reader…

Now you are ready to begin soldering.  The actual circuit is extremely simple – all you are doing is connecting a battery to these two wires, with a switch in the middle to turn the circuit on or off.  This is the circuit diagram from the CHDK wiki:

And here’s what my horrible soldering looked like in real life:

You will notice I have also covered all the contacts in a decent amount of hot glue.  This is partly for strength, and partly to avoid wires shorting if they wobble about inside the case.

The more observant among you may have noticed that I have hard wired the battery into the circuit, which is not a good thing if the battery runs out…  I was making this largely as a proof of concept, and also in a bit of a hurry.  Obviously if you intend to use your button for more than the life time of your battery, it would be a good idea to solder your button to a battery connector, instead of directly to the battery.

The final step is to test your release cable with your camera before shoving it all inside the container.  To do this simply boot your camera to the CHDK firmware, and then in the CHDK menu choose Miscellaneous Stuff – Remote Parameters – Enable Remote.  Now plug in your cable and try pressing the button.  If everything works go ahead and cram everything inside the container and glue the cable in place to make sure it’s secure.  Job done!


5 Responses to “DIY Shutter Release Cable For Canon Cameras with CHDK”

  1. bruno said

    Hi there. Good hack.

    Shouldn’t you wire a current-limiting resistor in series with the battery?


  2. Bill Stewart said

    If you’re powering it with CR2032 or similar coin cell batteries, they usually have a high enough internal resistance that you’re probably safe. (For instance, you can build LED throwies by connecting the LED directly to the battery, and it won’t smoke.) But if you’ve got actual documentation, you can tell what size resistor to use. (Also, why is the schematic showing a 3-volt lithium coin cell when the text says you want 5v? Is 3v really enough?)

    • Luo Bo Te said

      Thanks for the info Bill. Sadly I don’t have any actual documentation 😦 I will try and hunt some down when I get time. I have just tried the button with a 3V battery, but nothing happened. Although it’s still possible the battery was giving slightly less than 3V and the camera requires 3.3V – I don’t have the equipment to properly test it. All the discussions I have read on the net refer to a 5V signal (using 3V hadn’t even crossed my mind until your post!) but internet chat isn’t the most reliable source of information, so would be nice to know definitively.

      I’ll test it properly in a month or so when I go home and get my electronics stuff, and update the post if I find anything. In the mean time if anyone has any further info I’d be very interested!

  3. David said

    DO NOT TAKE THIS WITH YOU TO THE AIRPORT! You are asking for trouble.

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