Salvaging Lithium cells and circuits

salvaging-lithium-cells-and-circuits

Lithium cells outperform Nickel Cadmium and Nickel Metal Hydride in almost every way. But they also need a little bit more babysitting to get the most out of them. That comes in the form of control circuitry that charges them correctly and won’t let them get below a certain voltage threshold during discharge. We enjoyed reading about [Carlos’] Lithium cell salvage efforts as it discusses these concerns.

He wanted to salvage a Lithium power source for his projects. He had the three cell pack from a dead Macbook Pro seen in the upper left, as well as the single blown cell from a digital picture frame shown on the right. The three-pack didn’t monitor each cell individually, so the death of one borked the entire battery. He desoldered them and probed their voltage level to find one that was still usable. To prevent his project from draining the source below the 2.7V mark he scavenged that circuit board from the digital picture frame. A bit of testing and the system is up and running in a different piece of hardware.

Don’t be afraid of this stuff. If you learn the basics it’ll be easy to use these powerful batteries in your projects. For more background check out this charging tutorial.

Cellphone crowd-pleasers

When you start to think about the cellphone waste our society produces it can be quite daunting. How many cell phones have you had in recent years? Now multiply that by five billion cellphone subscribers. [Anthony Goh] and [Neil Mendoza] found something to do with a very minuscule portion of those left-overs; building interactive birds out of the old parts. You’ll have to check out their accomplishments in the video after the break as the image above doesn’t do them justice. Interactivity for the exhibit is provided by an Arduino, which communicates with one working phone via a serial connection. The phone can still make and receive calls, and controls parts from other, less functional cellphones. They can call each other, or receive calls from the audience.

Yes, there is art in garbage. But there’s also a lot of hacks waiting to happen. Take a look at the Nokia cellphone LCD feature and then start scavenging.

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Happy meal toy scavenging

We’re sometimes shocked at the electronics included in ‘disposable’ items. For some reason (our tech inclinations?) we’ve been getting those audio greeting cards from relatives and it kind of kills us to see the PCB, batteries, and speaker in what would have otherwise been a fully recyclable card. Now we’ve got several sets of those guts waiting around for our next project.

[David Cook] cracked open another disposable item, an Avatar action figure that came as a Happy Meal prize. What he found inside will actually be useful. There’s a battery holder for the three coin-cell batteries, A blue LED (for those blue LED hacks our commenters are so fond of), and a piezo speaker. There are some other discrete components that may be of use to you but the first three are certainly a boon for those that are  junk scavengers like us.

Has anyone else found some goodies inside these types of free toys? We’d love to hear about them in the comments. But for now we’re just glad to see the first good thing to come out of that annoying market saturation that accompanied the movie release.

Incidentally, [David’s] h-bridge writeup is our go-to reference for building quick motor controllers from parts on hand, or that can be purchased locally.

[Thanks Gron]

Scratch built jog wheel


[whatsisface] sent in his scratch built clone of a Griffin PowerMate. The PowerMate… is just a big knob, so it’s easy to see why more than one person has attempted this. [whatsisface] was inspired by a bit-tech post that did nearly the same thing, only they used the head out of a VCR for the knob. All the other components, like the optical encoder, are salvaged from a mouse, which we talked about in our scavenging How-To. He used a RC car tire for the actual knob. While we’re sure it works great in dirt, we’d probably go with the weight and inertia of the VCR head instead. Have a look at the video below to see the knob being used with the Volumouse software.

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Scavenging a WWVB module from an RC clock


[Chris Kuethe] shows how to scavenge what could be a pricey WWVB module from a radio controlled clock. WWVB is a special radio station in Colorado that transmits an atomic-clock-derived signal to RC clocks. The clock model he uses, the Atomix 13131, goes for less than twenty bucks. He also shares the link to another tear down of a Sony branded radio controlled clock for similar purposes. So if you’re looking for a cheap way to obtain a WWVB module, the scavenging method could be the thrifty solution you seek.

(Disclaimer: A sticker for an event I organize is in the background of the photos, it’s not meant to be there as product placement.)

How-To: Scavenge a mouse for parts

ps2 mouse opened
Chris Kiick posted about swarm robotics earlier in the week and today publishes his first Hack-A-Day How-To.

Old computer mice are being abandoned in droves. They’re tossed out because of dirt, obsolescence, or for being entirely too beige. Anyone who has a computer usually has more than one mouse and you can get them for pennies, if not free just for asking. Fortunately for the discriminating (read: cheap) hacker, these little widgets are chock-full of project parts. Today’s How-To will dissect a computer mouse, extract the useful parts, and give some ideas about how to use them.

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