Hacklet 39: Battery Power

3296371398740598106[robin] has a Red Camera (lucky!), an absurdly expensive digital video camera. As you would expect the batteries are also absurdly expensive. What’s the solution? Battery packs from cordless drills.

Cordless drills are interesting pieces of tech that can be easily repurposed; there are huge battery packs in them, big, beefy motors, and enough hardware to build an Automatic Cat Feeder or a motorized bicycle.

What if those old Makita batteries don’t charge? That usually means only one or two cells are dead, not the whole pack. Free LiIon cells, but you need to charge them. Here’s a single cell charger/boost converter that will do the trick.

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A problem faced by amateur radio operators around the world is the lack of commercial power. Plugging a portable shack into a wall will work, but for uninterrupted power car batteries are everywhere. How do you combine wall power and car batteries for the best of both worlds? With an In-line battery backup module.

9k=All of the projects above rely on charging a battery through wall power, and sometimes even that is impossible. Solar is where we’re headed, with solar LiPo chargers, and solar LiFe chargers. That’s more than enough to keep a smartphone charged, but if you want to go completely off the grid, you’re going to need something bigger.

[Michel] has been off the power grid 80% of the time since he installed his home PV system a few years ago. How’s he doing it? A literal ton of batteries, huge chargers, and a 5kW inverter.

 

Electric Bubblegum Board

The Mini Maker Faire in Atlanta was packed with exciting builds and devices, but [Andrew’s] Electric Bubblegum Boards stood out from the rest, winning the Editor’s Choice Award. His boards first emerged on Endless Sphere earlier this summer, with the goal of hitting all the usual e-skateboard offerings of speed, range, and weight while dramatically cutting the cost of materials.

At just over 12 pounds, the boards are lightweight and fairly compact, but have enough LiFePO4’s fitted to the bottom to carry a rider 10 miles on a single charge. A Wii Nunchuck controls throttle, cruise control, and a “boost” setting for bursts of speed. The best feature of this e-skateboard, however, is the use of 3D-printed parts. The ABS components not only help facilitate the prototyping process, but also permit a range of customization options. Riders can reprint parts as necessary, or if they want to just change things up.

[Andrew’s] board is nearing the 11th hour over at his Kickstarter page, so swing by to see a production video made for potential backers, or stick around after the break for some quick progress and demo videos.

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MSP430 alarm clock project

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[Markus] turn his breadboard LED matrix tinkering into an alarm clock which wakes him each morning.

Don’t be fooled by how clean his assembly work is. That’s not a fabbed PCB, it’s a hunk of green protoboard which a lot of point-to-point soldering on the back side. It’s driven by the MSP430 G2452 which is oriented vertically in this image. The two horizonal ICs are 595 shift registers which drive the LED modules.

We already mentioned the cleanliness of his assembly, but there’s one other really cool design element. On the back of the unit is what looks like a battery holder for two AA cells. He’s using just one Lithium Iron Phosphate battery (3.2V) which is in the upper of the two cavities. This let him cut the lower part of the holder at an angle to act as a stand for the clock.

Don’t miss the video which walks us through the user interface. It has what you’d expect from an alarm clock. But there is a really bright white LED which mimics a sunrise clock and it does more than just buzz one note when the thing goes off.

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LiFePO4 batteries work much better in a camera than NiMH

SAMSUNG

We agree with [Zapmaker] that Canon cameras chew through nickel metal hydride batteries. But we’re not going to use Alkaline because we think it’s wasteful. His solution is to use a battery that has a higher voltage rating. What you see here is a single lithium iron phosphate cell paired with a dummy cell to increase life between charges.

The reason that NiMH batteries don’t last very long is that they’re only rated at 2.4V. It won’t take long for that voltage to drop below the camera’s cutoff threshold since they didn’t start very high to begin with. But a single LiFePO4 cell has the same form-factor but produces 3.2V and maintains voltage well through it’s discharge cycle.

The size is right, but using one cell won’t work by itself. He built a filler for the other slot which is just a wood dowel with a screw all the way through it. The point was ground down and a bit of foil added to ensure a proper connection. We’d be interested to hear back about how this performs over the long term.

Electric mountain board with glove control

Last summer, we saw [Andres Guzman]’s electric mountain board tearing around the University of Illinois campus. He’s back again, only this time the board isn’t controlled with a PlayStation controller. [Andres] built a wireless glove to control his mountain board.

An Arduino and power supply is mounted to the glove. A 2.4GHz transceiver serves as the comm link between the glove and board. The speed control is handled by this flex sensor from Sparkfun. With the flex sensor held between the middle and ring fingers, all [Andres] needs to do to apply power is slightly bend his fingers.

There’s also a number of safety features built into the board. To enable power to the boards motor, there’s a dead man switch on the glove underneath the thumb. If [Andres] were to take a nasty spill, he would release the switch and the board would come to a stop. [Andres] also made sure the board would shut down if the wireless link was interrupted. The build seems pretty safe, even if he is tearing around his campus in the video below.

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Self-balancing unicycle 2.0

Focus Designs has a new version of their self-balancing unicycle for sale. This improves upon their original design in several ways. The battery pack has moved to LiFePO4, which is becoming more common in electric transportation. There’s also regenerative braking and fall protection which kills the motor when you fall off.

We’ve embedded their marketing video after the break. Our favorite part is the shot seen above: a guy on the unicycle cruising along next to a woman who is running. There’s nothing like sitting on your bum while some else exercises.

At any rate, from what we see in the video they’ve turned out a solid product.

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Electric mountainboard with wireless control

[Andres Guzman] is chauffuering himself around the University of Illinois campus thanks to his wirelessly controlled mountainboard. He added a brushless motor to drive the rear axel with the help of a chain. Power is provided by a Lithium Iron Phosphate battery which we’ve seen used in other electric vehicles due to its lightweight properties. A wireless PlayStation 2 controller operates the motor but steering remains a lean-to-turn system.