Monday, June 20, 2011

Wireless Remote Shutter for Canon/CHDK.

After spending a lot of time trying to make one wireless circuit to trigger the shutter. I was partly successful in receiving the signal (registering the press of a button in Remote Control ) with IR sensor TSOP1738, But the voltage at the signal was very weak to trigger the cam which needs LINK for the shutter to trigger. And me not being good at electronics, was unsuccessful with the simplest of circuits for Amplifying the signal to required voltage to trigger the shutter.

I gave up designing the circuit myself and was searching for a ready made wireless solution. A couple of them were on my list. One being the wireless toys. And the other was the chinese LED lamp which could be switched ON/OFF with any remote. After much of searching on the streets of market . I finally found a LED Lamp with Remote. Costed me around 4$ - Rs. 180.

Once home I found out

that this only works with the remote provided . And not any other as there is a chip for detecting which key has been pressed. On opening up the Lamp, we see the internals, a Board for the sensor and switch working. a Battery(6v) and the LED board.

The output is the Red Circle for the LED . Which will be used to trigger the shutter. And the sensor wires are the one in Blue Circle. The Lamp has a Rechargeable Battery( cheap lead acid I believe ), and a circuit board to hold the electronics and a switch.

Just hooked up the Voltmeter with the Output at the LED, and it showed up 4.2 volts. And it would be 0(zero) volts when switched off with the remote. :) :)

Detaching the LED board and the sensor.

To make the housing for the circuit I needed a box. And the choice was simple, Visiting Card box. Soft flexible plastic box. The battery, and the board were a snug fit, openings for the switch , sensor and USB slot were done by using heat (with the solder gun). The previous LED output of the Board, has to be wired to the USB slot. I had to perish a USB cable to get to the wiring. The wiring is explained in the CHDK wiki LINK.

I hooked up a small Led with a Resistor in the front panel. This Led would turn on when the voltage at the USB is 5V. Just to know if the switch is ON/OFF.

Hooked up everything and here is the result. In CHDK after enabling remote in the menu. The Cam focuses when the output is 5v (ON) state. Then quickly switching OFF and again ON will trigger the shutter. This sequence has to be repeated for each pic. This is the actual pic taken by the Cam, with wireless remote trigger. The USB cable sticking out is connected to the Camera and it triggers.

Everything Working and in house range of around 5-7 meters. And open air range for 5 meters.

Adding some cosmetics to the remote shutter box, here is the pic.