Replacing a Failed Ebook Reader Battery

Resurrecting a beloved piece of tech can be a trying process when fighting through the mild heartbreak — doubly so if the product has been discontinued. When their old Sony PRS-T1 e-book reader refused to charge after leaving it on their dashboard during a hot day, [Andrea Gangemi] decided to leverage a little techno-necromancy and hack together a fix.

[Gangemi] found the problem to be a battery failure, but there was nary a replacement to be found. An old Motorola mobile phone battery ended up fitting the purpose nicely. Cracking open the e-book reader, de-soldering the old battery and — after deciphering which pins were which — installing the new one was simply done with a fine, high temperature soldering iron tip and Kapton tape to avoid short-circuiting. But hold on — the new battery wouldn’t charge, and the reader displayed a message saying that the battery was over heating; irony, thou art cruel.

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Make Your Own Nuclear Battery

miami_nano
A commercial nuclear battery from City Labs.

A Betavoltaic cell is a device that uses a radioactive source of beta particles and a semiconductor p-n junction to generate electricity. Tritium, an isotope of hydrogen, is often used as the radioactive element. You may think that tritium is hard to obtain or even forbidden, however, recently you can find tritium in self-lightning key chains, and it is also used in watches and firearm night sights. The beta particles (electrons) from the tritium radioactive process causes phosphors in the device to glow, giving a light that can last for years.

[NurdRage] has just created a nuclear battery using tritium vials from key chains. After getting rid of the plastic containers, he sandwiches the vials between two small solar panels. That’s all! Instant power for the next 15 years. Of course, the amount of power you can get from this device is on the order of microwatts. The battery produces around 1.6 volts at 800 nano amps. He gets 1.23 microwatts, not much, but it is in fact more than the output of commercial units at 0.84 microwatts, for a ten percent of the cost. That minuscule amount of power is actually not easy to measure, and he does a great job explaining the circuit he used to measure the current.

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Diamond Batteries That Last For Millennia

Like many industrialized countries, in the period after the Second World War the United Kingdom made significant investments in the field of nuclear reactors. British taxpayers paid for reactors for research, the military, and for nuclear power.

Many decades later that early crop of reactors has now largely been decommissioned. Power too cheap to meter turned into multi-billion pound bills for safely coping with the challenges posed by many different types of radioactive waste generated by the dismantling of a nuclear reactor, and as the nuclear industry has made that journey it in turn has spawned a host of research projects based on the products of the decommissioning work.

One such project has been presented by a team at Bristol University; their work is on the property of diamonds in generating a small electrical current when exposed to radioactive emissions. Unfortunately their press release and video does not explain the mechanism involved and our Google-fu has failed to deliver, but if we were to hazard a guess we’d ask them questions about whether the radioactivity changes the work function required to release electrons from the diamond, allowing the electricity to be harvested through a contact potential difference. Perhaps our physicist readers can enlighten us in the comments.

So far their prototype uses a nickel-63 source, but they hope to instead take carbon-14 from the huge number of stockpiled graphite blocks from old reactors, and use it to create radioactive diamonds that require no external source. Since the output of the resulting cells will be in proportion to their radioactivity their life will be in the same order of their radioactive half-life. 5730 years for half-capacity in the case of carbon-14.

Of course, it is likely that the yield of electricity will not be high, with tiny voltages and currents this may not represent a free energy miracle. But it will be of considerable interest to the designers of ultra-low-maintenance long-life electronics for science, the space industry, and medical implants.

We’ve put their video below the break. It’s a straightforward explanation of the project, though sadly since it’s aimed at the general public it’s a little short on some of the technical details. Still, it’s one to watch.

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DIYing A Raspberry Pi Power Bank

Over the last decade or so, battery technology has improved massively. While those lithium cells have enabled thin, powerful smartphones and quadcopters, [patrick] thought it would be a good idea to do something a little simpler. He built a USB power bank with an 18650 cell. While it would be easier to simply buy a USB power bank, that’s not really the point, is it?

This project is the follow-up to one of [patrick]’s earlier projects, a battery backup for the Raspberry Pi. This earlier project used an 14500 cell and an MSP430 microcontroller to shut the Pi down gracefully when the battery was nearing depletion.

While the original project worked well with the low power consumption Pi Model A and Pi Zero, it struggled with UPS duties on the higher power Pi 3. [patrick] upgraded the cell and changed the electronics to provide enough current to keep a high-power Pi on even at 100% CPU load.

The end result is a USB power bank that’s able to keep a Raspberry Pi alive for a few hours and stays relatively cool.

Weaponizing Elementary Science Experiments

[austiwawa] was playing around with one of those simple linear motors people build as friendly little science experiments. There’s an AA battery in the middle of a set of magnets. When you put it inside of a spring it zips around inside until you run out of spring or magic pixies in the battery.

Of course, the natural question arose, “How do I make it go fast!? Like fast!” After making explosion and woosh noises for a bit (like any good hacker would) he settled down and asked a more specific question. If I made the coil the barrel of an air gun, and then shot the battery out… would it go faster?

So, he built an air cannon. It took some ingenuity and duct tape, but he managed to line the barrel with a copper coil. After that he built an experimental set-up, because making something dangerous is only okay if it’s science. That’s the difference between sensible adults and children.

He shot three “dead” rounds through the cannon, and got a baseline result. These dead rounds were made so by placing the magnets at the improper polarity to forego the motion-boosting properties. Then he shot three live ones through. It went measurably faster! Neat!

What’s the silliest thing you’ve ever seen properly characterized? Let us know in the comments below.

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ESP8266 Lullaby

The ESP8266 is certainly a versatile device. It does, however, draw a bit of power. That isn’t really surprising, though, since you would expect beaming out WiFi signals to take a little juice. The trick is to not keep the device on all the time and spend the rest of the time in deep sleep mode. [Marco Schwartz] has a good tutorial about how to use this mode to run for “years” on a battery.

[Marco] notes that even using a 2500 mAh LiPo battery, he only gets about 30 hours of operation without sleep. By putting the chip in sleep mode, the current consumption drops from about 88 mA to just over 8 mA. That’s still high, though, because the board has a power LED! By removing a jumper or cutting a trace (depending on the board), you can drop the current draw to about 0.08 mA (80 uA) when it’s not doing anything.

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See if You Can Reverse Engineer This Scrap Metal Battery

We got quite a few tips in about a paper from Vanderbilt about a cool scrap metal battery they’ve been playing with. They made some pretty bold claims and when we fed the numbers in they pretty much say they’ve got a battery you can make at home, that can hold half as much as a lead acid, can be made out of scraps in a cave (even if you’re not Tony Stark), charge super fast,and can cycle 5,000 times without appreciable capacity loss.  Needless to say that’s super cool.

Of course, science research is as broken as ever and the paper was hidden behind a paywall. Through mysterious powers such as the library and bothering people we were able to get past this cunning defense and read the paper. Unfortunately the paper reads more like a brag track than a useful experimental guide on how to build the dang battery. It’s also possible that our copy was missing some pages. Anyway, we want to do science!

Anyway, here’s what we know. The battery is based on an ancient battery called the Baghdad Battery. The ancient battery supposedly used iron and copper with a mystery electrolyte. The scrap battery, however, is made from scrap iron and scrap brass. The iron makes sense, but why brass? Well, brass has copper in it, and you can still get at it chemically even if it’s alloyed.

To that end, the next step was to throw some oxygen atoms in with those pesky Fe and Cu ones. The goal is to get a redox reaction going. If you do it right you can achieve pseudocapacitance. To to this the researchers used “common household chemicals and voltages” to anodize the iron and copper inside the brass. The press photo have them holding a gallon of muratic acid, if that helps. We don’t know, but if they can jam a few oxygen atoms in there then so can we!

After that it’s all about sitting the electrodes in a bath of potassium hydroxide. We guess you can scrape the inside of an AA for that. Anyway, the paper’s light on process but the battery seems really cool. They’re not pursuing this research for commercialization, instead going the OSHW route. They hope to get to the point where anyone can just grind up a bunch of scrap steel and brass, maybe throw it in a birdcage, anodize it, and get a super long life battery for grid use for less than a lead acid. If any of you manage to build one of these drop us a tip!