Category Archives: coin cell

Coin Cell Challenge: Jump Starting a Car

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Clearly a believer in the old adage, “Go Big or Go Home”, [Ted Yapo] has decided to do something that seems impossible at first glance: starting his car with a CR2477 battery. He’s done the math and it looks promising, though it’s yet to be seen if the real world will be as accommodating. At the very least, [Ted] found a video by [ElectroBOOM] claiming to have started a car with a super capacitor, so it isn’t completely without precedent.

Doing some research, [Ted] found it takes approximately 2,000 W to 3,000 W at 14 V to start the average …read more

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The Incredible Shrinking Coin Cell Battery Pack

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How’s it going with your project for the coin cell challenge? You can only use a single one, but Hackaday alum [Jeremy S Cook] has a great way to package coin cells into a sleek little power packs whether you need one, two, or even four.

[Jeremy] is building a wireless Wii nunchuk, so he needs a small battery that won’t short out or get punctured in the confines of the controller body. A single coin cell holder is already a bit bulky, and he needs to use two in series. He thought, why not try shrink wrapping them together? …read more

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Coin Cell Challenge: Use Coin Cell, Win Prizes

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Today, we’re calling all hackers to do the most with a single coin cell. It’s the Coin Cell Challenge, and we’re looking for everything from the most low-power electronics to a supernova in a button cell battery.

Electronics are sucking down fewer and fewer amps every year. Low power is the future, and we’re wondering how far we can push the capabilities of those tiny discs full of power. The Coin Cell Challenge is your chance to plumb the depths of what can be done with the humble coin cell.

This is a contest, and as with the tradition of …read more

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Hackaday Prize Entry: A PCB To Emulate Coin Cells

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The Coin Cell Emulator CR2016/CR2032 by [bobricius] homes in on a problem some hardware developers don’t realize they have: when working on hardware powered by the near-ubiquitous CR2016 or CR2032 format 3V coin cells, power can be a bit troublesome. Either the device is kept fed with coin cells as needed during development, or the developer installs some breakout wires to provide power from a more convenient source.

[bobricius]’s solution to all this is a small PCB designed to be inserted into most coin cell holders just like the cell itself. It integrates a micro USB connector with a 3V …read more

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Clever Battery Holder Hack Makes Brilliant Earrings

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We love seeing a thing get used effectively for other than its intended purpose, and this DIY LED Earrings project is a great example. [IdunnGoddess] liked the idea of making light-up LED earrings powered by a small coin cell, but an enclosure and power connection for the battery were sticking points. The solution? A googly eye after a few minor modifications turned out to be perfect.

A googly eye resembles a thin, flat, hollow plastic bulb. Choose one that’s just a bit bigger than the coin cell, and cut a slot in one end and a small hole in the …read more

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Edge-lit Pendants Show Two Layers are Better Than One

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Engraved acrylic lights up nicely with LED lighting. Simply engrave clear acrylic with a laser engraver, then edge-light the acrylic and watch the engraving light up. This badge made by [Solarbotics] shows how they used this principle when creating some pendants for an event that performed particularly well in the dark.

The pendants they created have two engraved acrylic panels each, and that’s about it. Two LEDs and a CR2032 battery nestle into pre-cut holes, and the engraved sides are placed face-to-face, so the outer surfaces of the pendant are smooth. By using some color-cycling RGB LEDs on one panel …read more

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Mitosis: Anatomy of a Custom Keyboard

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Ergonomic. Wireless. Low-latency. Minimalist. Efficient. How far do you go when you design your own open-source keyboard? Checking off these boxes and providing the means for others to do so, Redditor [reverse_bias] presents the Mitosis keyboard, and this thing is cool.

The custom, split– as the namesake implies — mechanical keyboard has 23 keys on each 10 cm x 10 cm half, and, naturally, a custom keymapping for optimal personal use.

Upper and lower PCBs host the keys and electronic circuits respectively, contributing to the sleek finished look. Key caps and mechanical switches were ripped from sacrificial boards: two Waveshare …read more

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Chronio DIY Watch: Slick and Low Power

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[Max K] has been testing the battery life of his self-designed watch under real-world conditions. Six months later, the nominally 3 V, 160 mAh CR2025 cell is reading 2.85 V, so the end is near, but that’s quite a feat for a home-engineered smart watch.

We’ve tipped our hats to the Chronio before in this Hacklet, but now that the code is available, as well as the sweet 3D-printed case files, it’s time to make your own. Why? It looks sweet, it plays a limited version of Flappy Bird (embedded below), and six month’s on a button cell is a …read more

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PSA: Don’t Let Kids Eat Lithium Batteries

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We get a lot of press releases at Hackaday, but this one was horrific enough that we thought it was worth sharing. Apparently, some kids are accidentally eating lithium coin cell batteries. When this happens with bigger cells, usually greater than 20 millimeters (CR2032, CR2025, and CR2016) really bad things happen. Like burning esophaguses, and even death.

The National Capital Poison Center has done some research on this, and found that 14% of batteries swallowed over the past two years came from flameless candles like the ones above. We know some of our readers also deal with batteries in open …read more

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