Please, Don't FAVE these photos without a COMMENT!
Check out my first photos with this "gizmo"
Important note on Camera Compatibility
While the actual connector for many cameras may vary, often they use
the same or similar control mechanisms. This trigger design expects
that the focus and shutter signals represent positive signals, and a
connection from either of them to the camera common causes current to
flow towards the camera common connection. This is true for many
Canons, Nikons, and Pentaxes.
The hole idea came on my mind because once in a while I take
naturalistic photos of animals and I was interested in using something
new to take photos at wild life from a different point of view than
usual telephoto lenses. My idea is to hide a camera closer to where
something will happen (e.g.: a passage trail for animals) and to make
that camera shoot inside action and far away from my position while
watching with binoculars or something like that.
This is also a good way to take sport photos as you can drive two cameras: one in your hand and the other even further away than usual distance covered by well known radio transceivers as Pocket Wizard. Depending to what you connect the Relay Switch box you can cover even kms of distance. The only problem is the time delay between the actual pressing of the PTT on trasmitter and the shot which is about half second: not bad, I would say in any case. I am pointing this out because this configuration won't be good for fast flash photography, but it's not the reason why I made it! This does not mean that you will have to take photos only in ambient light but you will have to demand your camera to trigger the hidden flashes.
SO, how does it work?! First of all, I want to state that I am not an engineer of any type (actually I studied architecture...quite different ;-) but I am stubborn enough to get to the end of a project that's on my mind).
Actually this type of schematic is not complicated at all but, after many experiments made by myself, I have been helped a LOT by an electronic website www.grix.it. Especially I would like to thank Wilcomir (who provided the schematic) and Giorgio25760 (who helped me with deep explanations when I had a technical problem).
Basically the current coming from the earphone was too weak (only 1,5V...AC!!!) to make a normal relay of 12DC operate, so there are other components to add "power" to the existing signal coming from the receiver earphone ( I keep saying earphone and not phoneS because you only use the tip of the min jack, so it's a mono jack).
you need a electrolytic capacitor (100 uF), two diodes (any of series 4000), a resistance (1000 ohm), a transistor (I used BC337) and, of course, the 12DC relay. You will also need to different female mini jack plugs for IN and OUT connections and a battery. I decided to make it run with a 12v battery but I also tested it with a 9V squared battery and it DOES work well. I just went for the smallest!...Probably the higher capacity of the 9V battery will make the hole thing last longer.
You don't need an ON/OFF switch because the transistor stops the circuit unless it receive an incoming signal: so the relay normally does not consume anything!
The gadget can also operate with other entrances compatible to earphones signal. For example you can connect it to a mp3 player and it takes photos every time you press play... Of course I find it less interesting for myself, but maybe someone of you will love it that way!
You tell me why and how you use it.
Personally, I was thinking to connect it to a mobile phone and when you make a call and the cellular rings, you take a shot! (nice but too long to wait for the line...)
Comments are welcome.