Often I have to take photographs of small objects–for example, when I’m selling items on eBay. Electronic flash is overkill for this kind of work, and video lights are bulky and hot. I decided to build miniature photo lights from small, efficient LEDs.
On eBay I found complete LED reflector bulbs for just $3 each. They are plug-compatible and identical in size and packaging to the little 12V quartz-halogen spotlights often used in track lighting (although the LEDs have a cooler light temperature of 6,000 Kelvin–very similar to cloudy daylight). All the distributors were in China, but I’ve never had any problems ordering components from Chinese sources. Sure enough, within 10 days I received my lights.
Since each unit was rated at 4W, I needed a 12VDC AC adapter rated to supply at least 40W. Fortunately this kind of switching power supply is commonly available as a power source for laptops and LED displays. I found a 50W unit for $5.
(Caution: Some adapters of this kind deliver much more than 12VDC when they are not fully loaded. Therefore, avoid powering just one light at a time.)
How to mount the lights? I wanted to use them in two sets of five, so that I could position each set on opposite sides of a subject. The angle of each individual light had to be adjustable, so that I could focus their combined beams around a small object, or point them at a larger object from farther away. I also wanted to be able to angle the lights up and down, or backward toward a reflective photographic umbrella if I needed diffuse, shadowless illumination.
The design that I came up with uses jointed arms, made from 3/4" oak and small aluminum angle brackets. Originally, the lights push-fitted onto a 3/8" brass peg. I later changed the design so that they screwed onto a ¼-20 threaded stud, which is a more common termination on a photographic light stand (plus it fits on a tripod). If you don’t have light stands or extra tripods, you can easily improvise something from a vertical 1" dowel screwed into a plywood base.
I chose oak as my construction material because I wanted to use wood screws to make the joints in the articulated arms. The screws would tend to work loose in softer wood. You can get an affordable piece of 3-1/2" x 3/4" oak from The Home Depot, where you’ll also find a length of aluminum angle, to make the brackets.
Download the cutting and drilling template.
MAKE Volume 34: Join the robot uprising! As MAKE's Volume 34 makes clear, there’s never been a better time to delve into robotics, whether you’re a tinkerer or a more serious explorer. With the powerful tools and expertise now available, the next great leap in robot evolution is just as likely to come from your garage as a research lab. The current issue of MAKE will get you started. Explore robot prototyping systems, ride along with the inventors of the OpenROV submersible, and learn how you can 3D-print your own cutting-edge humanoid robot for half the price. Plus, build a coffee-can Arduino robot, a lip balm linear actuator, a smartphone servo controller, and much more