Adding wireless capability to the snapshot sniper II

[-jeff]

The receiver specs say it requires 3.3 to 5.0 volts. Four AA in series is 6 volts or more depending on battery type. Not sure, but that might eventually fry the receiver. The receiver incorporates a linear voltage regulator to keep the voltage supplied to the components at 3.3 volts. Linear regulators are very inefficient. So, the closer you can come to 3.3 volts of input voltage, the less current the receiver will draw. Two or three AA in series will keep you in that range.

When I use this TX/RX combo I run the RX output into a microcontroller and let it do the level shifting timing and controlling the camera.

When the receiver receives the signal from the transmitter, it causes the corresponding pin on the receiver to go high (3.3 volts). Your camera wants to see the opposite. If you put a voltmeter on the shutter pin on your camera you will see about 3-4 volts depending on the camera. When you press the shutter button that voltage goes to zero causing the shutter to fire. In the idle state the pin is low. This is why your camera fires when you connect the receiver directly to the camera.

What you need is a way to invert the output of the receiver. The easiest way is with two general purpose NPN transistors. A couple PN2222 will do fine.

20220826105631-498bdf9e-me.jpg

When the receive port goes high, the two transistors will pull the shutter and metering low causing the camera to take a picture.

Don't worry about the zero knowledge. We are all born with zero knowledge. If you are willing to learn, you can make this happen.

[Warks]

I was using nimhs at 1.2v, so 4 of them was fine. But taking it account what you said about the linear voltage regulator, I'm now using 3 AA.

Thank you a lot for the schematics and all the explanations ! I followed it and it now works perfectly !
I did struggle a bit with the channels between the receiver and the transmitter not following the same order. But other than that, it all went very smoothly !

Thanks again Jeff ! I'll be in French Guiana in two weeks, I can't wait to test it in the field =)