Trying to create NOTC circuit to control camera flash delay

Thread Starter


Joined Sep 21, 2010
I have a camera that does not have a flash hotshoe that I'm trying to use with a remote flash. I was able to connect a cable that allows the camera shutter to trigger the remote flash. But it is triggering the flash a little too soon. So I want to build a circuit that will allow me to delay when the flash goes off by a few hundredths of a second. The cable that plugs into the camera simply has 2 wires that are normally open. When you press the shutter button on the camera, it momentarily shorts the cable and fires the flash. I'm guessing there is some simple NOTC relay chip that I can connect resistors to or a rheostat to allow me to adjust the delay so I can get the flash to fire at the proper time?

My electronics skill level from 1 to 10 is about a 2. So please pretend you are explaining the circuit to your grandmother. Thanks!
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Joined Aug 23, 2012
As what you described that two wires the one is common pin and the other one maybe connect to +V or GND, in this situation you need to try or using the model of your camera to google which one is right, and decide to using the TLC555 or ICM7555 to be a delay control, two kinds of IC can be triggered by common pin and GND pin, otherwise it will needs to add a stage of npn bjt to inverting the trigger edge.


Joined Feb 26, 2011
How old is your camera and how old is your flash?

On all cameras, old and new, the hot shoe and the pin in the middle is shorted when the shutter opens, a modern flash may only pass 5 or 6 volts through the contacts (ISO 10330 allows for up to 24V) and so modern cameras have hot shoes only capable of 24V max. Older flashes, the ones made during the 60's and 70's, may pass up to 60V through the hot shoe, which would eventually fry the contacts on a modern digital camera. Before the 60's, the sky was the limit with regards to hot shoe voltage, some voltages chucked out by the flash were as high as 400V!
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