I’m trying to build a remote shutter release for my camera. I have a relay connected so the shutter is activated when the relay is energized. I built this circuit to release the shutter when the trigger wire is broken, but I’m having trouble with getting the whole system to work.
I replaced the speaker and 1 microfarad capacitor with a LED, which lights up when the trigger wire is removed. But, when I insert a relay into the circuit, the relay buzzes and doesn’t activate the camera. I also tried connecting the relay after the LED, thinking the LED could half-rectify the output in case it was AC, but no go. What can I do to allow the circuit I built to activate the relay?
That’s a funny circuit to use with a relay. The speaker is driven by pulses while you want a relay to get DC. What are you trying to accomplish? Is it a timer or do you want it to trigger when the wire is broken?
Now, this one is triggered by a button press. This has the advantage of multiple exposures on the camera: one for each press (assuming the circuit has time to reset). Does your trigger mechanism require an open circuit or broken wire to activate?
Yeah, that’s not going to work at all. You’re better off using a circuit like one of these. The one on the right will give you a shorter trigger pulse,l which is all you need for a camera shutter. Replace the pusbutton switch with a resistor, say about 100 kOhms, and then connect a 10 k resistor to the 0.1 uF cap, and run your trigger wire from the other end of the 10 K resistor to Vcc. That should trigger a single relay cycle to activate your shutter when the wire is broken, instead of when the pushbutton is closed. Lower the value of the 22 uF cap to shorten the timing of the trigger pulse.
That’s completely the wrong circuit for what you want. Most of that circuit is about createing a buzzing noise, not creating what yuo need. You can make it work, but that’s like using a stero & amplifier to light a room by connecting a bulb where the speakers normally hook up.
Two easy techniques …
Get a microswitch that is spring loaded to the NC position. Then have your trip wire mechanically hold the switch in the open state. There is no power in the trip wire. Electrically connect the power supply through the microswitch to the shutter release. When the tripwire breaks, the microswitch closes & the shutter fires.
Might have a problem if the shutter relase won’t be happy with constant voltage applied until the power supply dies or you rescue the camera. That can be solved with either a time-delay relay or a 555 one-shot circuit to provide a one-time short burst of power to the shutter when the microswitch first closes.
Upside is that you can use thread or some other very very fine, hard to see, easy to break material for the tripwire since it doesn’t have to carry power.
2. Similar idea, but put power through the tripwire & have it hold a NC relay in the open position. Downside here is continuous power consumption, and not all relays are built to be continuously energizxed, i.e. 100% duty cycle.
One second throught, there is no advantage to my idea #2 over #1.
