Battery teardown to get at the cells inside


Most of what people call batteries are actually cells. All of the common disposable alkaline batteries from AAA to D are single cells. The exception is the 9v battery which actually has six smaller cells inside of it. [Tom] took a look inside three different batteries to see what cells they’re hiding. Since he no longer uses the batteries for their intended purposes the individual cells may find a new life inside of one of his upcoming projects.

The six volt lantern battery on the left has four cells inside of it. This is no surprise since each zinc-carbon cell is rated for 1.5V. There’s not much that can be done with the internals since each cell is made of a carbon rod and zinc electrolyte ooze (rather than being sealed in their own packages).

Moving on to the rechargeable PP3 battery in the middle he finds the 8.4V unit is made up of seven 1.2V nickel-metal hydride cells. Many of them were shot, but we’d love to see one of the intact cells powering something small like a bristlebot.

The final component is an old laptop battery. Inside are an octet of Lithium Ion cells. The majority register 0V, but a few have 0.4V left on them. This is not surprising. We’ve seen power tool packs that have a few bad cells spoil the battery. It’s possible to resurrect a battery by combining good cells from two or more dead units.

‘Vortex-drive’ for underwater ROV propulsion

This is [Lee von Kraus’] new experimental propulsion system for an underwater ROV. He developed the concept when considering how one might adapt the Bristlebot, which uses vibration to shimmy across a solid surface, for use under water.

As with its dry-land relative, this technique uses a tiny pager motor. The device is designed to vibrate when the motor spins, thanks to an off-center weight attached to the spindle. [Lee’s] first experiment was to shove the motor in a centrifuge tube and give it an underwater whirl. He could see waves emanating from the motor and travelling outward, but the thing didn’t go anywhere. What he needed were some toothbrush bristles. He started thinking about how those bristles actually work. They allow the device to move in one direction more easily than in another. The aquatic equivalent of this is an angled platform that has more drag in one direction. He grabbed a bendy straw, using the flexible portion to provide the needed surface.

Check out the demo video after the break. He hasn’t got it connected to a vessel, but there is definitely movement.

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Klackerlaken gets the common man excited about electronics

The Klackerlaken is a combination of LED throwie and bristlebot. The bauble is easy to build and really has no other purpose than to delight the masses. The diminutive devices were first seen in the wild at the 2011 CCC (Chaos Communications Camp) as a hands-on workshop. Check out the clip after the break and you’ll see why this really sucks in the spectators.

We’ve seen a ton of Bristlebots before (this tiny steerable version is one of our favorites) and were intrigued to see bottle caps used as the feet instead of the traditional toothbrush head. In fact, that video clip shows off several different iterations including two caps acting as an enclosure for the button cell and vibrating motor. Googly eyes on the top really complete the look on that one.

Decorating the robots with LEDs, fake eyes, tails, and feathers helps to temper the technical aspects that kids are learning as they put together one of their own. We’re glad that [Martin] shared the link at the top which covers the creations seen at a workshop held by Dorkbot Berlin. This would be a great activity for your Hackerspace’s next open house! Perhaps its possible to have follow-up classes that improve on the design, using rechargeable cells instead of disposable buttons, or maybe supercaps would work.

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MSP430-based wristwatch project

[Nav] is working on a scratch-built wristwatch. Although it is based on an MSP430 microcontroller, it’s not the ready-to-hack ezCronos that you might be thinking of. Instead, [Nav] started with a different TI development tool that we’ve looked at before, the ez430-F2013.

The breakout board for the F2013 is small enough to meet his needs, but still provides easy soldering with 0.1″ vias that break out each pin. To make sure the timepiece is accurate he added a 32.768 kHz clock crystal. A small, square, LCD screen acts as the face of the watch, but we didn’t find specific part information for the display.

Currently the watch can run for a few days on the CR2032. We’d bet some work with sleep modes for the microcontroller can help with that. The watch has a couple of buttons that let you control it, and [Nav] discovered that he could fit everything into the watch case for an iPod nano. That’s creative!

We’ve seen other hacks with tiny batteries. The next logical step here would be to swap out the disposable coin cell for something that can be topped off with an external charger.

$14 swarm robot, kilobot, is extremely cool

Reader, [Michael Rubenstein], sent in a project he’s been working on. Kilobot, as stated in the paper(pdf), overcomes the big problems with real world swarm robotics simulations; cost, experiment setup time, and maintenance. The robot can be communicated with wirelessly, charged in bulk, and mass programmed in under a minute. Typically, robots used for swarm research cost over a $100, so large scale experiments are left to software simulation. These, however, rarely include the real world physics, sensor error, and other modifying factors that only arise in a physical robot.  Impressively enough, the kilobot comes in far under a hundred and still has many of the features of its costlier brothers. It can sense other robots, report its status, and has full differential steer (achieved, surprisingly, through bristle locomotion). There are a few cool videos of the robot in operation on the project site that are definitely worth a look.

Color changing paint display


We’ve seen several creative projects from [Sprite_tm] and this one sets a new bar. He got his hands on some paint that changes color with temperature. By covering a circuit board with the paint then heating the circuits he’s created a heat actuated 7-segment display (his post is in Dutch). Three seconds at about 1 amp is enough to turn the black paint white. When the segment has been disconnected for about one minute the paint fades back to black. Now that we’ve seen his concept, leave a comment and tell us how you’d use it.

Serial hacking with an ATtiny2313


[Sprite_tm] automated a portion of serial hacking by sniffing out the baud rate using an ATtiny2313 and FT232 breakout board. The firmware assumes 8 data bits, no parity, and 1 stop bit (8N1). This is pretty much defacto among serial ports so it should work well, though some devices do use different settings. The auto detection routine can sniff rates as low as 110 baud and supports non standard rates. Released under GPLv3, the software is also supplied in hex format.  [Sprite_tm] has provided great project in past such as Working with VFDsControllable bristlebot, and AVR boost converter. Additional information regarding serial hacking after the break.

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