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 the Open 7400 Logic Competition and the recent Flashing Light Prize, we want to see what the community can come up with. The idea is simple: do something cool with a single coin cell and you’ll secure your fifteen minutes of fame and win a prize.
Three Challenges
To kick this contest off, we’re opening up three challenges to all contenders to the world heavyweight champion of button cell exploits. The first, the Lifetime Award, will go to whoever can run something interesting the longest amount of time on a coin cell. The Supernova Award is the opposite – what is the most exciting thing you can do with a button cell battery, lifetime be damned? The Heavy Lifting Award will go to the project that is the most unbelievable. If you think you can’t do that with a coin cell battery — lifting a piano or starting a car, for example — odds are you probably can. We want to see it.
Prizes and Rules
All Hackaday hardware hacking challenges need prizes, and for this one, we’re rolling out the red carpet. We’re offering up cash prizes for the top coin cell hacks. There are three $500 USD cash prizes, one for each winner of the Lifetime, Supernova, and Heavy Lifting awards. We’re not stopping there, because the top twenty builds overall will each receive $100 in Tindie credit, where the winners can cash in on some artisanal electronics sold by the people who design them.
What do you have to do to get in on this action? First, you need to build something. This something must be powered by nothing more than a single coin cell battery and must include some type of electronics. We also want this to be Open Source, and you’ll need to start a project on hackaday.io. The full rules are available over here, but don’t wait — the deadline for entry is January 8th, 2018.
We’re excited to see what the community comes up with, and who will find a production coin cell that’s the size of a dinner plate. This is going to be a great contest with overheating coin cells and tiny bits of metal flying across the room. This is going to be a contest filled with blinkies and wireless devices that run for far, far too long. Someone is going to misread the rules and tape together a meter tall pile of coin cells. It’s going to be awesome, so start your project now.
Quick question: is this restricted to primary cells like CR2023s, or are rechargeable coin batteries such as the LIR2032 permissible?
If you can justify calling it a “coin cell” then it counts. The key is explaining what you’re doing, what you’re using, and why.
OK I’ll take a LiR2477 then…
BRILLIANT!
+1
There should be extra points for using a Lithium Rechargeable cell as they store far less energy than a chemical energy cell.
NO THERE SHOULD NOT (or if there are, I will gladly take advantage of them)! Won’t give it away, but they are orders of magnitude better at certain things…
Small solar cell like the ones in garden lights???
Not funny.
Need to finish my miniature coin cell powered Tesla coil.
Fly swarters work okay maybe use the circuit from those joke shocking pens and make it really small. They are usually a single black blob encapsulated IC with an inductor.
I had a very similar idea. It could be fun to create the smallest taser possible. I have different plans, so feel free to make it if you see this.
Ha, me too! Draining it after stepping up the voltage and letting it go all at once is probably gonna be a good way to go about this challenge…
I once stacked a couple of used coin cells in a coin wraper (for an energy harvesting project). When I touched both ends, I got a decent shock (no spark, but I definitely felt it).
Not sure why, but I’ve had this same idea at the back of my head even before scrolling down to your comment.
I’m looking forward to someone making a functional Dreamcast VMU that runs on a coin cell and actually lasts longer than five minutes. ;)
short of replacing the guts with an atmega and some e-ink display, not really possible. The CPU is hungry.
and why not replace the guts with a low power cpu and some e-ink display right? :D
It’s going to take a long time to prove which project last the longest. Estimating won’t be too bad, but measuring will by definition takes ages.
Yep. Could go like this:
“I’ve made this device which blinks once every 3 months. Can I get my prize now or should we wait till 2022?”
I have you beat. Mine blinks once every 4 months and is expected to last through 2025. ;)
It sounds like an eBay auction.
Lemme change a variable in code and recompile. Ok now I’m up to 2027.
I think the problem is worse than that. I made a mini bar code reader in 2002 with a CR2023 in it. I recently found a box of them – with the original battery in – and they worked as soon as I swiped a bar code (there was no off switch). That is 15 years with a cell battery in it, and it is still going… So I can stick a new battery in and pretty much guarantee if you read one bar code a month it will still be going in 2032..
I don’t think ‘standby’ is counted as a working device though.
It would need to run a counter though to time those months. Or to charge a capacitor very slowly but that would have to be one without any loss or leakage.
Either way it’s less simple than it sounds.
I’ve had a device strapped to my wrist for years that runs continuously on a CR2016 coin cell, counting once per second with the LCD display always on. I just recently changed the cell, but I think the last one ran for about 4 years.
I think there might be a few HP-12 calculators (or related calcs) still work with the original coin cells.
Some of the newer Casio digital watches claim to last 10 years on a single coin cell, which I think is the maximum lifetime most coin cell manufacturers will guarantee no matter how little current you draw.
Even if it does something more continuous, it could be a rather long time.
Clearly some thought needs to go into how they judge ‘longevity’
Would a button cell be okay?
As a chemistry guy, you should make some battery piles out of actual coins, and technically it would be a coin cell.
;-)
Oooooh, I like that idea!
I’ve actually done that before.
Wouldn’t that be a battery as opposed to cell?
Bingo! A cell is one unit only and a battery is a “battery of cells”. So what people call AA batteries are actually AA Cells.
Peel one open and see what’s inside.
I am not so keen to peel one open but that doesn’t matter as 1.5 Volts is the voltage of a cell. On the other hand a 9 Volt “batter” has 6 cells as 6 times 1.5 is 9
I had considered entering a device that would blink a 110 volt light bulb with a AA battery in the blinky light challenge. I may have to dust off the idea I had for the Supernova category.
Is using a supercapacitor for high surge currents allowed?
Is it powered from a single coin cell? If yes, then I think you’re on the path to the Supernova award :-D
If the car starter is being ran off of the single cell by means of an electric to chemical energy booster… like a rocket engine ignited by the coin cell to in turn transfer the “amplified” heat into a steam generator to turn over more heat to convert into further steam for the generator and then split off for a super capacitor bank for starting a car … and maybe further… Would that be an acceptable bending of the rules?
No that wouldn’t be acceptable, however if you could directly turn the coin cell matter into useful energy to directly start the car I think they might allow it.
e=mc2
In this case, making a key fob to turn on a nuclear reactor counts.
I was thinking the same, as I am sure most are too. :)
Does a coin cell powered wspr beacon exist yet?
Never heard of one in my browsing the interwebs, but would be easy to test. Perhaps a modification of this: http://www.sparkbangbuzz.com/easy-ten/easy-ten.htm ?
Does cutting open the cell and burning the lithium to accomplish something count?
(Maybe I should actually read the article)
According to the rules, it has to include some type of electronics, and it can’t have another power source. If you do that, I think you should use the flaming battery in a thermoelectric generator that powers a circuit.
There’s actually quite a lot of lithium in a AA. More than enough to spontaneously ignite in water.
Even tiny coin cells tend to produce a fairly large explosion if they are presented with a reasonable current for even a few seconds. Heating lithium in an enclosed metal container isn’t good to stand too close to when you watch it. Wouldn’t think there was enough lithium to do anything useful with. Maybe a really tiny heat engine and a controlled reaction.
So what is the most powerful coin cell can we buy? I see a few hours wasted on google for me. :)
CR2477 is rated at 1Ah.
… In the article I found after 10 seconds of Googling. Might be wrong.
Depends on how strict you want to be with your definition of ‘power’, 20mA draw is the spec for a 2477. You can squeeze 30mA from a CR2032 without too much of a lifespan hit. I don’t know what the short circuit max is.
Using a CR2477 in a micropower circuit may take years to claim the Lifetime Award!
B^)
So the CR2477 has 1AH @ 3v. I think starting a car could be done…..
http://cpc.farnell.com/panasonic-electronic-components/cr2477/battery-lithium-coin-cr2477-3v/dp/BT05723
A stack of four in a cigarette lighter plug. [ with some diodes so it doesn’t explode ]
You could charge a car a bit like an emergency single use phone charger…
Patent that :D
Something like this exists already and I have used to start my car when the battery was dead. It’s not very big.
Need more voltage, don’t mind spending a few more pennies…
https://uk.rs-online.com/mobile/p/coin-button-batteries/5268560/
I just had a silly thought, get about 500KG of these, strap them together, run electric car…. only need 36CM of them to get upto 144v, then 2000 stacks there after….
WTF, if that exist then why don’t they use them everywhere? I mean imagine two of these in a digital caliper, it would last a month in the off position!
But certainly in keylights and such they would be better than those 150mA type cells that are not much smaller.
Does it count if I start a microeconomy where we use coin cells as literal coins to be exchanged for goods and services?
2032s have been standing in for nickles for decades already.
NOT GUILTY!
Hahaha… what we did as kids to get sweets out of those turn-wheel vending machines… Sometimes the coin will expand and you could just keep turning the wheel until the whole vending hopper was completely emptied!
Hang on a minute Frank… You’ve probably aided in the Super Nova level prize entry… a dead short is technically “some form of circuitry”… just a circuit that is a little bit on the short side ;-)
Ahhh … So you service vending machines then ??
There really should be a “lol award” for flagrant ‘misinterpretation’ of the rules.
I’ll go get the first aid kit….
1) The Lifetime Award, will go to whoever can run something interesting the longest amount of time on a coin cell … LM3909
Can I make a 3kA, 4.3ns fast charger? Translation: does the coin cell have to exist *after* the demonstration?
You don’t understand the word “Supernova”?
vacuum tube circuit with battery in tube
Just wait till I bust a move with my EM4325. BEST RFID SOIC
Can someone reverse-engineer where this depleted coin cell came from? I was bodged on the motherboard of a fax machine.
https://i.imgur.com/AjyefBY.jpg