While batteries are cheap and readily obtainable today, sometimes it’s still fun to mess around with their less-common manifestations. Experimenting with a few configurations, Hackaday.io user [will.stevens] has assembled an aluminium-air battery and combined it with a joule thief to light an LED.
To build the air battery, soak an activated charcoal puck — from a water filter, for example — in salt-saturated water while you cut the base off an aluminium can. A circle of tissue paper — also saturated with the salt water — is pressed between the bare charcoal disk and the can, taking care not to rip the paper, and topped off with a penny and a bit of wire. Once clamped together, the reaction is able to power an LED via a simple joule thief.
Continue reading “Stealing Joules From An Aluminium-Air Battery”
We all do it — park our cars, thumb the lock button on the key fob, and trust that our ride will be there when we get back. But there could be evildoers lurking in that parking lot, preventing you from locking up by using a powerful RF jammer. If you want to be sure your car is safe, you might want to scan the lot with a Raspberry Pi and SDR jammer range finder.
Inspired by a recent post featuring a simple jammer detector, [mikeh69] decide to build something that would provide more directional information. His jammer locator consists of an SDR dongle and a Raspberry Pi. The SDR is set to listen to the band used by key fobs for the continuous, strong emissions you’d expect from a jammer, and the Pi generates a tone that varies relative to signal strength. In theory you could walk through a parking lot until you get the strongest signal and locate the bad guys. We can’t say we’d recommend confronting anyone based on this information, but at least you’d know your car is at risk.
We’d venture a guess that a directional antenna would make the search much easier than the whip shown. In that case, brushing up on Yagi-Uda antenna basics might be a good idea.
Thieves in Paris have been stealing money with the clever use of a vacuum. Not just bits of change here and there, they’ve stolen over 500,000 euros. They noticed that Monoprix supermarkets use a pneumatic tube system to transport rolls of cash to and from the safe. Realizing this was the weakest point in the security, they simply drilled a big hole in the tube, hooked up a vacuum and sucked the cash out. Forget lock picking or safe cracking, this had to be ridiculously easy.
The thieves are still out there, sucking their way to riches. At this point, they’ve hit 15 locations. Their luck has to run out some time right?