Wireless doorbell battery monitor

wireless-doorbell-battery-monitor

We know exactly what [Dan] is going through. We also bought a cheap wireless doorbell and are plagued by the batteries running down. When that happens, the only way you know is when people start pounding on the door because you're not answering the bell. Well no more for [Dan]. He built a backup system which monitors the voltage of the batteries on the chime unit. You can see the small bit of … [Read more...]

Motorizing this trycicle

building-and-electric-trike

[Kaj] wanted to help out an aging family member by building them an electric tricycle during international Hack Day back on August 11th. He mixed in some reused parts with some new ones and ended up with bike that lets the rider troll other cyclists. Apparently when serious riders see an older man on a trike gaining on them they pedal like mad to make sure they don't suffer the embarrassment of … [Read more...]

UPS with dead batteries reborn as a whole-house power backup

whole-house-ups

[Woodporterhouse] must deal with regular power black outs in his area. He recently converted a rack-mount uninterruptible power supply to feed a portion of his mains wiring. This one is not to be missed, since he did such a great job on the project, and  an equally remarkable job of documenting it. It's one of the best examples we've seen of how to use Imgur as a project log. The UPS still … [Read more...]

Measuring the capacities of different battery brands

batteries

Being the smart consumer he is, [Denis] usually looks at the price per pound when comparing similar products at the grocery store. When it came time to buy a few AA batteries, he didn't have any data to go on. To solve his little conundrum, [Denis] decided he would test several brands of batteries and see which one gives him the most bang for the buck. After bringing home a haul of a dozen … [Read more...]

Another take on using ‘dead’ batteries

smaller-battery-psu

Here's another circuit that can be used to squeeze the remaining potential from supposedly dead batteries. Just like the AASaver, we see this as a useful prototyping tool, providing juice for a breadboard even though it's not reliable enough for long-term use (the batteries are just about through after all). First off, the image above shows rechargeables instead of alkalines. We don't recommend … [Read more...]

Things to do with your laptop batteries when they’re dead

18650_things_to_do_with_dead_laptop_batteries

[Roy] over at GeekDad had a dead laptop battery on his hands, and decided he would disassemble it to see what useful things he could do with the cells inside. He mentions in his article that even though your laptop might be convinced that its battery is toast, more often than not just one or two cells are damaged. This may not be news to all of our readers, but is worth pointing out to those who … [Read more...]

Engine Hacks: Electrified Datsun is the ultimate engine swap

white_zombie_electric_car

Forget the Tesla Roadster, we want an electric car like [John Wayland’s] White Zombie! If it wasn’t plastered with sponsor stickers and the like, you would never realize that this otherwise unassuming ‘72 Datsun 1200 is an absolute beast of a car. The gas engine that used to provide a mere 69 horsepower was swapped out for a pair of custom-built electric motors which propel the Datsun to … [Read more...]