Published January 11, 2015 by Scott Allen Burns
I had an opportunity to do a project with the University Primary School students back in February of 2012, and this is the result of that activity. I built a seven-color LED light wand that the kids could control. I took time exposures of them as they danced around and flashed different colors. I also had flash units off to the side so I could capture them mid-motion. See below for more details on how I made these pictures.
The LED Light Wand
Here is a video of the LED light wand in action:
It was a quick-and-dirty build, but the final product was definitely functional. Here is a teardown:
The wand comprises the following components:
- battery pack (4 AA batteries)
- three normally-open SPST switches
- three 700 mA constant current modules (BuckPuck model 3023-D-N-700 link)
- 9W (3 x 3W) RGB LED link
- thermal tape link
- ping pong ball (cut open on one end and placed over LED)
They are connected this way:
Stage and Photo Settings
The photos were taken with a Canon HS500 compact camera. Most any camera will work as long as it has manual controls. These are the settings I used:
- 15 sec exposure
- f8 aperture
- neutral density filter on
- 100 ASA
Of course, the camera was placed on a tripod.
During the exposure, I manually triggered two flash units located off to each side. This allowed me to capture an image of the child mid-motion. The strobe units were Vivitar 283s with a Varipower attachment that let me reduce the light output. As I recall (not sure about this), I turned the power all the way to the minimum. I put each flash unit inside a cardboard box to shield the stray light from hitting the camera or the background. I built a trigger switch to fire the flash units.
Here is a layout of the setup:
I applied gaffer tape to the floor so the kids knew the boundaries of where they could perform.
My friend Stephen Cartwright built a similar device based on this circuit design. Being a skilled craftsman, he created a much more refined version:
Here are some images he and his wife Amy created:
Time Exposures by Scott Allen Burns is licensed under a Creative Commons Attribution-ShareAlike 4.0 International License.