If internet service providers go down, how are we going to get our devices to communicate? Project Byzantium aims to create an “ad-hoc wireless mesh networking for the zombie apocalypse.” It’s a live Linux distribution that makes it easy to join a secure mesh network.
[B1tsh1fter] has put together a set of hardware for running Byzantium on Pis in emergency situations. A Raspberry Pi 2 acts as a mesh node, using a powerful USB WiFi adapter for networking. Options are provided for backup power, including a solar charger and a supercapacitor based solution.
The Pi runs a standard Raspbian install, but uses packages from the ByzPi repository. This provides a single script that gets a Byzantium node up and running on the Pi. In the background, OLSR is used to route packets through the mesh network, so that nodes can communicate without relying on a single link.
The project has a ways to go, but the Raspberry Pi based setup makes it cheap and easy to get a wide area network up and running without relying on a single authority.
We’re all familiar with hybrid gas-electric cars these days, but how about a hybrid scooter that uses supercapacitors instead of batteries? Our hats are off to [Alex] from Labs Bell for the almost entirely-DIY conversion.
The hybrid idea is to drive the vehicle’s wheels with electric motors, but generate the electricity with a normal gasoline engine. This allows the hybrid to control the engine speed almost independently of the wheel motors’ demand for power, allowing the gas engine to run at its most efficient speed and charge up batteries with the extra energy. As an extra bonus, many hybrids also use regenerative braking to recoup some of the energy normally wasted as heat in your brake pads.
[Alex]’s hybrid scooter does all of the above and more. Since the stock vehicle is a 50cc scooter, any increase in acceleration is doubtless welcome. We’d love to see the scooter starting from stop with a full charge. Using supercapacitors as storage instead of batteries is a win for charging efficiency. In urban stop-and-go traffic, the natural habitat of the 50cc scooter, the regenerative braking should help further with gas consumption.
What’s most impressive to us is the completely DIY hybrid control unit that takes some simple inputs (wheel speed and throttle position) and controls regenerative braking, the gas engine’s throttle, etc. Since the hybrid control system is currently under development, there’s even a button to switch between different trial algorithms on the fly. Very cool!
Oh yeah, and [Alex] points out the fire extinguisher on-board. He had occasion to use it for his hybrid motorcycle V1. Safety first!
[Raphael] has a motorcycle he’s constantly working on, and for him that means replacing the battery occasionally. Tired of the lead-acid batteries that have been used for 100 years now, he took a look at some of the alternatives, namely lithium and the much cooler supercapacitor option. A trip to the local electronics distributor, and [Raphael] had a new supercapacitor battery for his bike, and hopefully he’ll never need to buy another chunk of lead again.
The battery pack is built from six 2.7V, 350F caps, a few connectors, and a handful of diodes. These are lashed together with rubber bands to form a 16V, 58F capacitor that makes for a great stand-in for a chunk of lead or a potentially puffy lithium battery.
[Raphael] put up a walkthrough video of his battery pack where he shows off the enclosure – an old, empty lead acid cell. He also goes through the back current protection and his method of balancing the supercaps with a few diodes.
Lithium ion supercapacitors. No, not lithium ion batteries, and yes, they’re a real thing. While they’re astonishingly expensive per Farad, they are extremely small and used as the first line of defense in some seriously expensive heavy-duty UPS installations. Here’s a Kickstarter using these supercaps to replace the common AA, C, and D cell batteries. Even better, they can be recharged in seconds.
For each size battery, the caps used actually have a slightly higher energy density than a similarly sized dollar store battery. By adding a little bit of circuitry to drop the 3.8 Volts out of the cap down to the 1.5 V you expect from a battery, this supercap becomes a very expensive rechargeable battery, but one that can be recharged in seconds.
This is one of those crowdfunding campaigns we really like: an interesting tool, but something we just can’t figure out what the use case would be. These lithium ion supercaps are too expensive to be practical in anything we would build (save for a Gauss pistol), but the tech is just too cool to ignore. If you have a use case for these caps in mind, please leave a note in the comments.
Somewhat relevant Mouser link.