Another take on using ‘dead’ batteries

Here’s another circuit that can be used to squeeze the remaining potential from supposedly dead batteries. Just like the AASaver, we see this as a useful prototyping tool, providing juice for a breadboard even though it’s not reliable enough for long-term use (the batteries are just about through after all).

First off, the image above shows rechargeables instead of alkalines. We don’t recommend this as the circuit has no cutoff feature and the 0.7V input for the boost converter surely is below the recommended low-voltage limit for those cells. But that aside, we like the diminutive board which solders onto the end of a battery pack. It uses an SC120SKTRT which is a variable boost regulator capable of outputting 1.8-5V depending on resistor choices. You can leave the resistors off and it will default to 3.3V, set the output explicitly, or roll in some potentiometers and use your multimeter to tune the output.

This regulator costs more than the MCP1640 used in the AASaver, but it appears to use less passive components making for a smaller footprint. At a total of $3.50 plus the PCB (which will be a snap to etch at home) this is another great option to top off your next parts order.

[Thanks Uwe]

Things to do with your laptop batteries when they’re dead

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[Roy] over at GeekDad had a dead laptop battery on his hands, and decided he would disassemble it to see what useful things he could do with the cells inside. He mentions in his article that even though your laptop might be convinced that its battery is toast, more often than not just one or two cells are damaged. This may not be news to all of our readers, but is worth pointing out to those who might not be aware.

With the bad cells separated from the good, [Roy] thought up a couple of different uses for his newly acquired batteries. His initial idea was to power an LED flashlight that was made to run on the 18650 cells he recovered from his laptop – not a stretch of the imagination, but definitely useful. The second use he came up with was to pair two of the cells together in order to simultaneously power an Arduino and some small Lego motors.

[Roy] lays out all of the standard caveats you would expect regarding the care and feeding of the lithium cells, and even suggests rebuilding the laptop battery as an option for the more skilled members of his audience.

Now we understand that dismantling and re-using old laptop cells is not necessarily groundbreaking, but it’s definitely something that’s worth a bit of discussion. [Roy] admits that his two ideas fall far short of the “18650 Things” his article title suggests, so how about adding a few of your own?

If you have stripped down some laptop batteries to salvage the cells, let us know what you did with them in the comments – we would be interested in hearing about it.

Engine Hacks: Electrified Datsun is the ultimate engine swap

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Forget the Tesla Roadster, we want an electric car like [John Wayland’s] White Zombie!

If it wasn’t plastered with sponsor stickers and the like, you would never realize that this otherwise unassuming ‘72 Datsun 1200 is an absolute beast of a car. The gas engine that used to provide a mere 69 horsepower was swapped out for a pair of custom-built electric motors which propel the Datsun to 60 miles per hour in under two seconds.

The electric motors supply 500 horsepower and a staggering 1250 foot pounds of instant torque, providing one hell of a ride. The car is powered by 12 custom 29.6V battery packs which provide 2,400 Amps of current each! Aside from laying down a quarter mile in under 11 seconds, White Zombie can make a 90 mile trek before requiring a recharge.

Needless to say, this impressive car takes plenty of people by surprise each time [John] hits the track. Continue reading to watch one poor sap learn the hard way that his brand new Maserati is no match for White Zombie.

[via Discovery]

[Read more...]

Apple laptop batteries vulnerable to firmware hack

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When you think about hacking laptops, it’s highly unlikely that you would ever consider the battery as a viable attack vector. Security researcher [Charlie Miller] however, has been hard at work showing just how big a vulnerability they can be.

As we have been discussing recently, the care and feeding of many batteries, big and small, is handled by some sort of microcontroller. [Charlie] found that a 2009 update issued by Apple to fix some lingering MacBook power issues used one of two passwords to write data to the battery controllers. From what he has seen, it seems these same passwords have been used on all batteries manufactured since that time as well. Using this data, he was subsequently able to gain access to the chips, allowing him to remotely brick the batteries, falsify data sent to the OS, and completely replace the stock firmware with that of his own.

He says that it would be possible for an attacker to inject malware into the battery itself, which would covertly re-infect the machine, despite all traditional removal attempts. Of course, replacing the battery would rectify the issue in these situations, but he says that it would likely be the last thing anyone would suspect as the source of infection. While using the battery to proliferate malware or cause irreversible damage to the computer would take quite a bit of work, [Charlie] claims that either scenario is completely plausible.

He plans on presenting his research at this year’s Black Hat security conference in August, but in the meantime he has created a utility that generates a completely random password for your Mac’s battery. He says that he has already contacted Apple to in order to help them construct a permanent fix for the issue, so an official patch may be available in the near future.

[Thanks, Sergio]

Fixing motorized window shutter battery problems

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Living in a brushfire-prone area, [Erich] had a set of roller shutters installed to protect his home. Mains power can be spotty in emergencies, so the shutters are powered by NiMH batteries which are housed inside the shutters’ remote control units. After encountering a good handful of dead batteries, he decided it was time to search around for a better means of powering the shutters rather than pay another $80 AUD for batteries that he knew would fail in short order.

After disassembling the shutters and the remotes, he found a litany of problems. The remotes are ATMega-based, so he assumed the programming was robust, but he found that the charging algorithm was quite poorly implemented. The batteries were allowed to get extremely hot while charging, a result of the fact that charging was done for a set period of time rather than monitoring battery voltage. Additionally, the shutter motors required a 4 amp instantaneous current when activated, something that seemed to contribute to the quick draining of the 1500 mAH battery packs.

To remedy his issues, he upgraded to a much larger sealed lead acid battery pack, which he mounted in a wall cavity. The remotes were tweaked to add a modular power plug, enabling him to easily connect and disconnect the remotes as needed. Not only did he save a ton of money on constantly replacing batteries, he’s got a nice 12v power supply in the wall that he can tap into at will.

Wireless mouse Li-Poly retrofit with USB charging

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It’s no secret that wireless mice can eat through batteries pretty quickly. Rather than keep a fresh supply of AAs on hand at all times, [Phil] decided he would convert his mouse to use a rechargeable lithium polymer battery instead.

This isn’t the first time we’ve seen a cell phone battery crammed into a mouse to increase capacity, but we think this one has been done quite nicely. [Phil] managed to fit a 2.7 – 4.2v Li-Poly battery in the mouse’s palm rest, where there was a little extra empty space. The battery can be charged from any USB port via a custom-built charging module, which he constructed using a MAX1555 charge controller. Another custom-built circuit resides in the space previously occupied by the AA batteries, which uses an MC340063 DC to DC converter to drop the battery’s voltage down to the 1.25v required by the mouse.

The only part of the build that [Phil] is not pleased with is the power switch on the bottom, but since you rarely see that, we could care less. We think it is quite well done, and with a second version already in the works, we anticipate that it will get even better.

Be sure to check out [Phil’s] video tour of the hack, which you can see below.

[Read more...]

Music tank puts the boom in boombox

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When you think of Memorial Day weekend, what comes to mind? Well around here, all we can think about is this tank cum boombox that Instructable user [Elian_gonzalez] put together.

This build is actually the third version of his Music Tank, and it comes with all sorts of improvements over previous models. The tank is primarily constructed out of plywood, with cavernous compartments for holding all of its goodies. In its capacious body, the tank sports a 60 Watt stereo system that powers a pair of external speakers mounted on either side of the turret. The turret itself contains an air-powered cannon built from PVC tubing, which we imagine can be used to shoot a multitude of different projectiles.

While the concept itself is pretty cool, the tank happens to be nearly self-sustaining as well. The tank has a pretty deep battery well and uses a 50w home made solar panel to help keep things topped off while in use. [Elian] does not specify a total running time, but we imagine that it can go for hours on a nice, sunny day.

Keep reading to see a long video walkthrough of the Music Tank MK3 in action. [Read more...]

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