Planet Arduino

The uninterruptible power supply was once a standard fixture in the small office/home office as a hedge against losing work when the electrons stop flowing from your AC outlet. Somewhat in decline as computing hardware shifts away from dedicated PCs toward tablets, phones and laptops, the UPS still has a lot of SOHO utility, and off-the-shelf AC units are easy to find. But if your needs run more to keeping the electrons flowing in one direction, then you might want to look at [Kedar Nimbalkar]’s programmable DC backup power system.

Built inside a recycled ATX power supply case, [Kedar]’s project is heavy on off-the-shelf components, like a laptop power supply for juice, a buck converter to charge the 12 volt sealed lead acid battery, and a boost converter to raise the output to 19.6 volts. An Arduino and an optoisolator are in charge of controlling the charging cycle and switching the UPS from charging the battery to using it when mains voltage drops.

 If you need a DC UPS but would rather skip the battery, you could try running a Raspberry Pi with electrons stashed in a supercapacitor. Or if you’ve got an aging AC UPS, why not try beefing it up with marine batteries?

[Thanks for the tip, Morris]

[Yannick] got a hold of a 100W LED diode recently, and like any self-respecting hacker, he just had to turn it into a ridiculously over powered flash light.

The tricky thing about these diodes is that they need a high amount of DC voltage, anywhere from 32-48V typically. [Yannick's] using a 12V sealed lead acid battery coupled with a 600W constant current boost converter which ups it to 32V at around 3.2A. He also managed to find a giant aluminum heat-sink to keep the diode from getting too hot. A 120mm fan helps to keep the heat sink nice and cool, which allows the light to be run constantly without fear of burning it out. But just in case he also has an Arduino monitoring the temperatures — oh and it provides PWM control to adjust the brightness of the light!

To focus the flashlight he bought a proper lens and reflector which can be mounted directly to the diode. At full power the LED puts out around 8500lm, which is brighter than almost all consumer projectors available — or even the high beams of a car!

This isn’t the first time we’ve seen a 100W LED diode being used as a flashlight, but the builds are definitely getting fancier!