#Arduino -> Flash Trigger via Laser for Watterdrops

Today I have been asked if I can write something about mine Nikon flash Arduino trigger video that I have put on Youtube.

And here it is, description, schematics, video and sample pictures.

The idea has already been seen on the Internet. Arduino is controlling photo resistor on which laser beam is pointed. When resistance changes itself because of the drop that is cutting beam then Arduino is triggering Nikon camera after the amount of time specified with one trim capacitor which can be between 0 and 1023, but I have divided it with 2 so that I have better control of the delay. All information is displayed on 2x16 LCD display. Also to be able to take picture of drops colliding it’s necessary that speed of the drops be 10 drops/sec so I have implemented one button for that with proper code behind it.

I have also 4 buttons and 2 led diodes on the board. Buttons that I have are reset for resetting of the electronics, debug that is switching debug mode on and off, drops that is designed to count drops per second and ready button that is used when I’m taking pictures so that when drops are falling fast I don’t trigger camera every time when they are going down. Led diodes that I’m using are green for power and yellow for visual notification when the trigger is trigged.

Here is the final schematics that I’m using right now.

For simplified solution with cables I’m using standard audio cables with 3.5mm stereo jacks on both sides, so I can use same cables for other purposes as well. I have also modified Nikon cable remote so that it has 3.5mm female stereo jack built in for simple use with trigger and without it.

Here are few pictures of the whole setup.

Of course code behind is in thisĀ file available for download.

Simple instructions.

  1. when the program is loaded it will display Ready on the second line
  2. when drop breaks laser beam then instead of Ready on display will be Busy until you press Ready button
  3. offten because I have laser box about 1m above the surface delay is needed between 150-220 ms

For drops counter I’m doing like this.

  1. switch to drops counter with drops button
  2. then I try to create drops stream with about 1 drop per second with help of the normal digital watch and by changing delay I set Arduino to recognize that as 1drop/sec
  3. now the only thing left is to configure drops stream to 10 drops/second for colliding watterdrops

Here are couple of pictures captured with this setup and pictures of colliding drops are to come.

And here is the video on YouTube.