In order to consistently photograph something like milk drops the usual method uses a high-end camera ($500 and up), Speedlite flash ($300 and up) and an optical electronic delayed flash trigger ($120 and up).
There are lots of DIY circuits for this purpose, but they still require a good camera and a high-end flash unit.
And you have to manually open the shutter requiring the photo to be taken in a darkened room.
Here's how you can consistently take the same photos with an simple circuit, inexpensive point and shoot camera, no additional flash unit, all without fumbling around in the dark.
The video above shows the ease of use of this rig and some of the better splashes of the hundreds that I've captured.
I've concentrated on milk drops, but this can be used for many different things. The separation between the laser and the detector could be hundreds of feet apart, or bouncing off mirrors...
Thanks, and have fun spilling milk!
-Brett @ SaskView
Step 1: Materials
Self-Adhesive backed Velcro
Small picture frame (for the plate glass insert)
Eye drops (for the dropper bottle. I poured out the contents as I believe anything
purchased at a dollar store should never be applied to one's eyeballs!)
Here's what you'll need for the circuit (I don't think your local dollar store will have these so you might try an electronics distributor like Digi-Key):
Part/Value Digi-Key Part #
4 .01 uF 50V metal film Caps P4513-ND
3 1.0 uF 50V Ceramic Caps BC1162CT-ND
1 10 uF 35V Electrolytic Cap P818-ND
1 1K Ohms 1/4 W resistor 1.0KQBK-ND
1 22K Ohms 1/4 W resistor 22KQBK-ND
2 120 Ohms 1/4 W resistors 120KQBK-ND
2 200 K Ohms .5W Multi-turn Pots CT94EW204-ND
1 Green LED P14228-ND
1 Red LED P14224-ND
1 LM556CN timer IC 296-6504-5-ND
1 7404 inverter IC 568-2921-5-ND
1 Photodiode PNZ300F-ND
Please note that the schematic has been revised to use new photodiode.