[Tom] wanted to try his hand at high-speed photography and needed some equipment to get things rolling. Not wanting to spend a ton of money on a lighting rig or trigger mechanism, he decided to build his own. In a three part series on his blog, he details the construction and testing of his high-speed setup along with the improvements and lessons learned along the way.
His adventures started out with a small off-brand Cree LED clone and an ATiny15L that was collecting dust in his workshop. He built a simple circuit that would trigger the LED to light his subject, which in [Tom’s] case was a bowl of milk. Rather than using a motion or sound trigger, he opted to mount a small piezo to the bottom bowl, firing the LED any time a droplet hits the bowl’s surface.
The pictures he took were decent, but he knew he could get better results. He purchased a new, more powerful Cree LED, and wrote a small terminal program that allows him to tweak his flash parameters using his laptop. The results he gets now are far better – in fact, he has a whole gallery of pictures you can check out.
If you want to delve into high-speed photography as well, all of the schematics and code can be found on his blog.
Sometimes, sitting in a windowless office can drive you crazy. Adding a little bit of life and color can really help. [Gripen40k] did this by building a biosphere. He didn’t have any windows though, so he made an LED light on a PIC based timer. What is interesting is what he did with a thermistor. The Cree LED bulb that he salvaged was going to be submerged in the water, so he had to do some workarounds to keep from over heating the biosphere. Read the project log for more details.
[PodeCoet] sent in this mod he did to a Spider Fire flashlight. These things are unbelievably bright, they use Cree LEDs that are so intense, they can ignite paper. [PodeCoet] notes that they run on fairly expensive batteries. Instead of buying some rechargeable ones, he decided to customize and hack his torch. He added a custom charging circuit and a Lilon battery as well as a boost-converter circuit and a status LED. We like the idea of having a rechargeable lamp, but he has lost his water proofing. If anything, you should go there to see his nicely done smd charger pcb as well as the pictures of his test run, burning some paper.
As some people have pointed out in the comments, this flashlight could not have started that fire. This one could though.