DIY – Remote flash trigger with opto-isolator : Part – I

DIY: Remote Light Trigger with opto isolator  to protect camera. 

Recently i decided to photograph a lot of figurines / curios which were lying around at home. For this, i needed to setup a product  table with a pure white background and also the right set of strobes around it.  Well, i had 2 strobes from ProPhoto and only one  Yangano flash for my 450D. This lead to a delima on  how to  get pure white background and still leave 2 strobes for lighting the product itself. Not wanting to invest in one more flash, i scratched my head and remembered that my dad had an old Vivitar flash from the Canon film days. The problem was, that it was really old and i had no way of syncing it with the other flash / strobes, so this resulted in more head scratching , conclusions :-


  1. The flash probably had a trigger voltage which would blow out modern cameras or triggering devices
  2. The flash had a very old adaptor which modern cords did not fit into

More head scratching, and then volia !!! The results of a misspent youth (tinkering with electronic circuits vs girls) came to the rescue. Figured i needed a remote light trigger with an opto-isolator. As a need its easy enough, but how do you get one, again i was not really willing to invest top dollars in this and wait for something of ebay to be delivered in a month from now.

After scouting the internet and downloading some circuits diagrams it did not seem a particularly complex to build. Next issue was how do i get the required parts in my local electronics market? Faridabad is not exactly the most happening marketplace for modern electronics, so took the only possible route, checked with the local shop as to what key components they had  and tried some experiments to see if i could make the circuit work with those.

After some tinkering came up with this final schematic

Remote Flash Trigger Schematic

Well that’s the basic circuit, construction and other details are here …

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7 thoughts on “DIY – Remote flash trigger with opto-isolator : Part – I

  1. Hi there. Very interesting schematic.
    I cannot undestand what is the last component you draw on the right, the one between the BC547 collector and the 1K resistor. Could you explain it? Thanks

    Simone (Italy)

  2. Hi, could you check your link where the details of the project are posted? the link is not working and I’m very interested in the project.


    Well that’s the basic circuit, construction and other details are here …

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