Jump Start Your Car With A Drill Battery

August 16, 2018 by Lewin Day 99 Comments

Sometimes, you move to a new city, and things just aren’t going your way. You’re out of cash, out of energy, and thanks to your own foolishness, your car’s battery is dead. You need to jump-start the car, but you’re feeling remarkably antisocial, and you don’t know anyone else in town you can call. What do you do?

It’s not a problem, because you’re a hacker and you have a cordless drill in the back seat of your car. The average drill of today tends to run on a nice 18 volt lithium battery pack. These packs are capable of delivering large amounts of current and can take a lot of abuse. This is where they come in handy.

Typically, when jump starting a car, another working vehicle is pulled into place, and the battery connected in parallel with the dead battery of the disabled vehicle. Ideally, the working vehicle is then started to enable its alternator to provide charge to the whole system to avoid draining its own battery. At this point, the disabled vehicle can be started and its alternator can begin to recharge its own battery. After disconnecting everything, you’re good to go.

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Welcome To The Internet Of Swords

August 16, 2018 by Tom Nardi 22 Comments

As has been made abundantly clear by the advertising department of essentially every consumer electronics manufacturer on the planet: everything is improved by the addition of sensors and a smartphone companion app. Doesn’t matter if it’s your thermostat or your toilet, you absolutely must know at all times that it’s operating at peak efficiency. But why stop at household gadgets? What better to induct into the Internet of Things than 600 year old samurai weaponry?

Introducing the eKatana by [Carlos Justiniano]: by adding a microcontroller and accelerometer to the handle of a practice sword, it provides data on the motion of the blade as it’s swung. When accuracy and precision counts in competitive Katana exhibitions, a sword that can give you real time feedback on your performance could be a valuable training aid.

The eKatana is powered by an Adafruit Feather 32u4 Bluefruit LE and LSM9DS0 accelerometer module along with a tiny 110 mAh LiPo battery. Bundled together, it makes for a small and unobtrusive package at the base of the sword’s handle. [Carlos] mentions a 3D printed enclosure of some type would be a logical future improvement, though a practice sword that has a hollow handle to hold the electronics is probably the most ideal solution.

A real-time output of sword rotation, pitch, and heading is sent out by the Adafruit Feather over BLE for analysis by a companion smartphone application. For now he just has a running output of the raw data, but [Carlos] envisions a fully realized application that could provide the user with motions to perform and give feedback on their form.

Incidentally this isn’t the first motion-detecting sword we’ve ever covered, but we think this particular incarnation of the concept might have more practical applications.

Theo Jansen Invents A Faster, Simpler, Wind-Powered Strandbeest

August 16, 2018 by Steven Dufresne 25 Comments

[Theo Jansen] has come up with a n intriguing wind-powered strandbeest which races along the beach with surprising speed and grace. According to [Jansen], it “doesn’t have hinging joints like the classical strandbeests, so they don’t get sand in their joints and you don’t have to lubricate them.” It’s called UMINAMI, which appropriately means “ocean wave” in Japanese.

There are only videos of it in action to go on so far, but a lot can be gleaned from them. To make it easier to keep track of just a single leg, we’ve slowed things down and reddened one of them in the banner animation. Those legs seem to be providing a push but the forward motion is more likely supplied by the sails. The second video below shows it being pulled along by the type of strandbeest we’re all more used to seeing.

What follows is an analysis and best guess about how it works. Or you can just enjoy its graceful undulations in the videos below.

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