Remote shutter releases are simple add-on devices you can use to trigger your camera when you don’t want to disturb it on a tripod or before a long exposure. These remote triggers can cost as little as $3 for a simple button or quite a bit more if you want to remotely control every aspect of your digital camera.
instructables Of camera
An Instructables user by the name of nk dtk went one step further than just buying one and pulled a MacGyver by making his own remote trigger out of a cable and soda can tab. The resulting device is dirt cheap and so simple that anyone could build one.
All you need is a 2.5-millimeter male-to-male cable, the pop-cap tab from a soda can, and a pair of pliers to pull it all together.
First, you need to take your tab with the little ring part still mostly intact and bend it 90-degrees at the halfway point. After that, you slip the tab onto one of the ends of the 2.5 cable so that it goes through the tab’s ring. Clamp it all down with your pliers to make sure it stays, and you’re all set.
Trigger Of camera
To trigger your camera, all you need to do is push the part of the tab sticking up against the cable end; when the tab comes in contact with the cable tip, it creates a complete electrical circuit and triggers the camera shutter. Nk dtk says that his makeshift shutter release works perfectly with his Canon T4i/650D and should theoretically work with any camera that uses a 2.5-millimeter cable for its shutter release.[ Source :- Techhive ]