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Intervalometer w/ 3.5mm audio jack

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New Member
Hi all,

The problem in a nutshell: I am trying to construct an intervalometer using an mp3 or equivalent sound track played from a normal 3.5mm audio jack.

In detail: In certain cameras (DSLR's), there is a small 2.5mm stereo port which allows you to connect a remote release cable. Basically what this does, as far as I understand, is that it shorts the sleeve with the ring (ground with right hand channel), making the camera take a shot.

(Tip/ring/sleeve terminology: http://en.wikipedia.org/wiki/TRS_connector)

What I've managed to do successfully is instead of buy an expensive remote release from Canon, I just got a 2.5mm male-male cable, stuck one end in the camera and performed the above mentioned short to take a photo. Works like a charm.

The problem comes in when you want to take more than one shot (many hundreds) and specified intervals. You could make a circuit to do this for you:

Or, as I have tried, write a program for a calculator to do the same thing. You just specify the interval between each shot, start the program and away goes the camera, click click click.


My question is: If I get a 2.5mm to 3.5mm converter, connect the camera to my iPod or whatnot, is there any sound file I can create that does the same effect? IE output max voltage on the right channel for X seconds, output 0 volts repeat.

If that is possible, I think it wouldn't be difficult to make different sound files with different intervals, or maybe even a program for my Symbian phone where you can specify the interval you want and away it goes.

My background: Electrical engineer but that seems like decades ago so take it easy on me =)

Thanks in advance for your help.


New Member
Intervals used in time lapse are pretty variable, anything from 5 seconds to an hour. Still, for testing purposes 10secs would be ideal.

As for which model camera, it really shouldn't matter - All DSLR's have a 2.5mm jack for remote shutter release.

So, is it possible?
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