Disposable camera flash slave

flash slave

[Greg Lipscomb] was working on this disposable camera based slave flash when he stumbled into his macro photography project. Slave flashes are used as fill lighting and can be triggered by several different methods. Greg’s project uses a photocell and a microcontroller for trigger and timing. It also makes sure the flash stays charged. He concedes that this design is a bit complicated, but he went with it because he didn’t have any silicon controlled rectifiers available. The microcontroller would be too slow, but his Canon 10D uses a pre-flash before the actual photo, so the slave has a built in delay from that first flash.


  1. Nick Bennett says:

    I’m really curious to see the quality of the flash fill lighting. Wouldn’t you know it, as soon as I drop $500 on a D50 body I start thinking about dropping more on remote flashes and all that jazz. Maybe this way I can save myself some money and kill some time between paychecks before I go buying an SB-600.

  2. Farglingrads says:

    What is really great is getting several thousand of those things and wiring them up in parallel along the road. When you trigger it, it looks like horizontal lightning. It was great, but it was too expensive. Totally freaks out the motorists.

  3. BruceR says:

    I can’t believe he could not find a cheap trigger for sale, eBay has hundreds. Why do we have to find excuses to pull stuff apart and make new stuff. Be truthful with yourself, embrace your innner hacker/maker.

  4. thenobot says:

    OMG — It took 10x the time to build and test this complicated timing circuit than to just wire up a photocell -> SCR -> flash PC cord and do it right the first time.

    Here’s an example of what you can do with an SCR and a flash, but this time using sound as a trigger…


    It’s the simplest circuit ever.

  5. Two things to note. This circuit recharges the flash each time, for a predefined amount of time. It also delays for the pre-flash that on some cameras can not be turned off. Also, I wanted to use parts that I had lying around. An SCR is not easy to find. Some Radio Shacks have a Triac, part 276-1000 i think, but they are no longer being sold. There are much easier ways of doing things, but nothing gives you the control that a microcontroller gives. That was the purpose of this project. It was a learning experience with microcontrollers. I even have some pins left, so I could build a Flash cancelling device. Where the disposable camera detects how much light is being emitted, and then stop the flash when enough light has been released.

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