Category Archives: 2017 Coin Cell Challenge

Remember Your Birthday For Fifty Years

Our Coin Cell Challenge competition has turned up some amazing entries, things that we wouldn’t have thought possible from such meagre power sources. Take [Vishnu M Aiea]’s entry for instance, a device which he claims can light up as a birthday reminder every year for up to fifty years.

At its heart is a modified Arduino Nano clone that draws a measured 608 nA from a CR2450N. From the specification of the cell he has calculated the 50 year maximum figure, as well as a possible 29 years for a CR2032 and 64 years for a CR2477. He does however …read more

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LED Tree Brings Gravity to Christmas

Here’s a fun entry into our coin cell challenge. The power source is the actuating force in [Frank]’s blinky LED Christmas tree, which takes advantage of the physical structure of coin cells and our old pal gravity to roll out some holiday cheer. Talk about forward voltage!

We love the concept, and the circuit couldn’t be more simple. A coin cell is released at the top of the tree and rolls down a series of angled foam board railings covered with 1/4″ copper tape. As the coin cell travels, the negative terminal shimmies along the face of the tree, which …read more

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BrewBuddy is a Home Brewer’s Best Friend

Whether coffee, tea, or beer is your jam, brewing is a delicate pas de deux of time and temperature. Proper brewing of any of these beverages can elevate the experience from average to amazing. With this in mind, [Marcelo] created a time and temperature tool to dial in his beer-brewing process.

BrewBuddy is a complex application-specific timer with an integrated thermometer. It lets him program time and temperature profiles for both the mashing process and the boiling process and store up to 10 steps for each. BrewBuddy doesn’t control the brewing temperature, but it does unify temperature-taking and time-marking into …read more

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This Is The Last Weekend For The Coin Cell Challenge

This is it. This is the last weekend you’ll have to work on the most explosive battery-powered contest in recent memory. This is the Coin Cell Challenge, and it’s all ending this Monday. You have less than 48 hours to create the most amazing thing powered by a coin cell battery.

Right now, we’re looking at the entries to the Coin Cell Challenge, and there are some real gems here. Did you know the Rickroll Throwie maddeningly distributed around the dorms at Cornell is an entry? Yes, with just a coin cell, an ATtiny85, and a piezo, you can rickroll …read more

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Take the Coin Cell Challenge This Weekend!

The year is drawing to a close, and we have a weekend project for you to while away the remaining hours. Take the Coin Cell Challenge!

The point of the challenge is to do something interesting with a coin cell. That’s it! It’s a challenge that can be as simple or as involved as you want. Low power is where it’s at these days, so if you’ve never used the hardware sleep modes in your favorite microcontroller, that would make an excellent challenge entry. Show us what you’re able to do with short wake periods, and talk about when and …read more

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LiquidWatch is Dripping with Style

Some of the entries for the 2017 Coin Cell Challenge have already redefined what most would have considered possible just a month ago. From starting cars to welding metal, coin cells are being pushed way outside of their comfort zone with some very clever engineering. But not every entry has to drag a coin cell kicking and screaming into a task it was never intended for; some are hoping to make their mark on the Challenge with elegance rather than brute strength.

A perfect example is the LiquidWatch by [CF]. There’s no fancy high voltage circuitry here, no wireless telemetry. …read more

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Joule Thief Steals in Favor of Christmas

A lot of things tend to get stretched during the holiday season, like shopping budgets and waistbands and patience. This year, [Chris] is stretching the limits of both the mini breadboard and the humble 1.5 V LR44 coin cell with his joule thief-driven LED mini Christmas tree.

With the push of a micro momentary, the joule thief circuit squeezes enough power from an LR44 to boot an MSP430 microcontroller, which needs 1.8 V – 3.6 V. After boot, the micro takes control of the joule thief circuit and milks it whenever the voltage falls below 3.2 V. This tree may …read more

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Posted in 2017 Coin Cell Challenge, blinkenlights, Holiday Hacks, how-to, joule thief, led hacks, leds, LR44, Microcontrollers, msp430, xmas tree | Leave a comment