(click images for better view)

After building a few flashlights with switches and white LEDs, I wanted to program the device for something more interesting to adults (well, technical minded adults like youself). I thought the time-fountain project looked pretty neat, even if was a little over-engineered. It took just a bit of programming to create a digital strobe with millisecond accuracy. The strobelight works great for looking at fan blades while in motion or water dripping from a reproducible source. My device has 2 buttons, so I chose the following user interface:

• Push both buttons simultaneously to toggle strobelight on/off
• Push button 1 to increase flash rate (hold down for nonlinear increase)
• Push button 2 to decrease flash rate (hold down for nonlinear decrease)

Since it’s software, you could just as easily create some other interface. Sure this circuit could be built using a 555, but how would you reprogram it to change the duty cycle, UI, or nightlight modes?

By the way, since the current drain is so low, the device pulses a "soft-on soft-off" sequence about once every thirty seconds when turned off. You have to love nanowatt technology.

(click to enlarge)

Parts count:

• 1 Picaxe 08M microcontroller
• 6 resistors
• 2 white LEDs
• 2 pushbutton microswitchs
• 1 3-pin programming header
• misc wire, project case, a piecce of protoboard, a battery holder

The strobe also has a pretty cool alternating light fade-in, fade-out night light feature. The schematic is shown above and some sample code is here. Although simple, the strobe works well for watching water drops hang midstream from a large container with a small hole or catching a ceiling fan appearing to stand still, even as you feel the breeze from it.

This code is explicitly released under the GPL. And this page is licensed under a Creative Commons Attribution 2.5 License.  

Write me if you find this project useful. Link to this page if it is relevant..

Strobe effect may be psychologically damaging or cause flashbacks to a pre-color cinema era. This project is provided without any warranty.