This instructable shows you how to make a really easy and simple circuit, that protects your new camera from high trigger voltages in old flashes. It is completely safe and will not damage the cameras circuits!
It is better than those slave adapters that "look" for a flash, and then quickly activate the flash, since those adapters can be set off by other cameras. If you're at a party, that can be quite annoying.
Step 1: What You Need:
- general soldering equiptment
- a sense of electronics
- an Optocoupler with triac output (i.e. MOC3062)
- 2 capacitors ( 10 ÃÂµF )
- 3 resistors ( 500, 1M, 30...80 ohms)
- a casing (optional, I got mine on ebay)
- a battery
Step 2: The Circuit:
The circuit is pretty simple and streight forward.
-The Optocoupler in the middle isolates the camera from the flash. If you don't know what an optcoupler is or what it does, check out wikipedia first
-R1 and C1 form a highpass. this is in case the output of the camera is a triac. with out the highpass, the current folwing through the led and the camera could keep the cameras triac open.
- The same goes for R3 and C2
- Now R2 is to limit the current though the LED of the optocoupler. you will have to adjust this depending on you optocoupler and battery you are using. Also keep in mind, that there could be a voltage drop inside of the camera which you have to consider! (it took me like 2 hours till I figured that out!)
Step 3: The Case:
I got my self an adapter, that would give cameras that only have a hotshoe an PC cord connector.
I got in on ebay:http://cgi.ebay.de/ws/eBayISAPI.dll?ViewItem&rd=1&item=260237775993&ssPageName=STRK:MEWN:IT&ih=016
I hoped, there was enough room inside to fit the circuit and the batteries.
Well the circuit barely fit, but the battery had to go outside...
if you squeeze everything into the case, please make sure that none of the highvoltage contacts or cables from the flas get to close to those that go towards the camera.
Also after everything is done, measure the voltage on the contacts that go to the camera before connecting it! Better safe than sorry!
Step 4: The Result:
ofter squeezing everything inside, I got a battery clip from an old motherboard and glued it to the side of the adapter.
And that is it. you can now connect pretty much any onld flash to you camera and don't have to worry about triggervoltages or anything!
Step 5: How to Use:
now you just put the adapter on the camera and either mount the flash on the adapters hotshoe or use the PC cord.
I like the PC cord alot, because it gives you alot of new lighting possibilities!
I hope you enjoy. If you have any questiones, just ask!