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An Electronic, Battery-less Dice

video An Electronic, Battery-less Dice

Update: A complete Instructable for this is here: Faraday For Fun: An Electronic Batteryless Dice

A Microcontroller, AVR Tiny13 based electronic dice, that does not use any battery or any normal power source. Instead it derives its power from a voltage generator based on the Faraday principle using a coil wound over a tube and a magnet inside the tube. To use the dice, just shake the circuit a few times and it produces a random number between 1 and 6 and displays it on the LEDs. Background music: Por Una Cabeza by Carlos Gardel

34 comments

Sep 11, 2008. 7:40 AMzanfr says:

you could lose the diodes and use a smaller "goldcap"

Sep 11, 2008. 10:27 AM

Gadre (author) says:

Diodes are necessary to convert the alternating voltage being produced by the Faraday generator into DC voltage to power the circuit. The current implementation doesnt use a Goldcap, but a normal electrolytic capacitor, 4700uF. Using a goldcap, even a smaller value goldcap, would require too much shaking to charge up the capacitor.

You can see all the details of this in the new Instructable I posted:
Faraday For Fun: An Electronic Batteryless Dice

Sep 11, 2008. 10:35 AMzanfr says:

use a denser coil and neodymium magnet also i always thought caps could smooth AC to DC (hence their ample use in power supply filtering) anyways i have used caps before on a nixie PSU i made to do just that; of course it was full DC some AC remained but if it saves you components; especially since u unload DC cap into the LEDs it doesnt matter i think...

Sep 14, 2011. 2:05 PMstatic says:

Yes inductors can be used to acquire power supply filtering than capacitors alone. The ting to keep in mind is that a coil design that make a good filter, may not make a coil that works well for power generation, and vise versa. At this low power of power production using an inductor could sap away too much power, beside extreme filtering isn't needed here. BTW; neodymium magnets are used in this project .

May 8, 2008. 6:00 PMkenny789 says:

ohh now i understand you shake it and that charges the cap and thats what powers it. very nice but wont that make ac current not dc?

Sep 14, 2011. 1:41 PMstatic says:

Most if not all mechanical means of creating electrical current first produce AC. Than that AC is the turned into DC. In some generators by the mechanical switching provided by an commutator, and brushes that act as a high speed mechanical switch. In other generators rectifiers are used. As Gadre stated solid state rectifier are used with this generator

Jun 17, 2008. 7:26 AM

kcbford1 says:

it makes AC current but, you use 4 diodes in the circuit to regulate the alternating currents.

Nov 23, 2010. 11:45 PMwareneutron says:

it is so great

Jan 4, 2008. 6:02 PMMyself says:

That was a nice demonstratable, but isn't it supposed to be an instructable?

Jan 22, 2010. 5:55 PMbears0 says:

he has an instructible for it here www.instructables.com/id/Faraday-For-Fun-An-Electronic-Batteryless-Dice/

Jan 5, 2008. 9:40 AMMyself says:

Oops, mea culpa: I didn't realize that videos and slideshows [http://www.instructables.com/id/The-InstructableSlideshowVideo-Tabs..../ aren't intended to be instructables] and should not be construed as such. (Replying to my own post so others can be similarly educated.)

Apr 8, 2009. 9:03 AMEirinn says:

I didn't know either and i thank you for posting that re-reply

Jul 28, 2009. 12:09 PMzaphodikus says:

I read your "Programming and Customizing the AVR micro" - nice project.

Oct 14, 2008. 2:16 PMjunits15 says:

thats pretty cool

Mar 18, 2008. 8:10 PMtrekman says:

I found the video. I saved this as a favorite and then looked it up and clicked on it and when it loaded it showed the video link. So now I just need help to build one. Nice show and tell but no info to build one. Why did you put it on Instructables if all you wanted was to show it off? I really hope you add the missing info to it.

Mar 18, 2008. 7:46 PMtrekman says:

To anyone: I use Internet Explorer but do not see any video link. I just see a box titled "enbed code" and the box with the email, print, favorite and flag links in it with all the comments listed under the box. This sounds like a simple project but I am a beginner. I do not know what an AVR Tiny 13 base is. I would like to see a schematic and this video (where ever it is). I hope you will help me and all the others who want more info. Thanks for anything.

Jan 8, 2008. 11:05 AMunitedelectric says:

Great project. Question on the linear alternator: are you doing a full-wave rectifier to produce dc? Also, there is no such thing as a "radially magnetized" neo magnet. How are you getting the magnetic flux to travel through the coil perpendicularly? Binding the magnets south-to-south and north-to-north with iron spacers would concentrate the flux radially (doable, but tough) this is a fundamental weekness in all shake designs I've seen. Thanks for the vid though.

Jan 8, 2008. 12:34 AMdhoncave says:

could it be hack?to the owners advantage? i still trust the traditional dice

Jan 4, 2008. 7:27 AMiKill says:

very, Very VERY cool im might build it if i can get everything from my local radioshack, do they sell neodymium magnets and leds there?

Jan 4, 2008. 7:47 AM

Gadre (author) says:

You can get neodymium magnets from www.amazingmagnets.com. Leds from Radioshack, yeah sure.

Jan 4, 2008. 7:53 AMiKill says:

so they dont sell magnets there... i can get stuff offline though i havent got a credit card

Jan 7, 2008. 6:38 PMthewoodcarver says:

Michaelshas neo magnets if there is one near you , I think when I was last there they went for $4 or so

Jan 4, 2008. 8:00 AM

Gadre (author) says:

Radioshack has these magnets: http://www.radioshack.com/product/index.jsp?productId=2104068&cp=2032058.2032229.2032262&parentPage=family

You could try with these.

Jan 5, 2008. 3:58 AMJ50Nunlimited says:

awesome! i love "shake n' shake" that produces power for the circuit. now i can make a "shake-shake" power generator, add some springs, connect it to a capacitor, save power and use it as a battery =] (*carry it around whenever you're moving) i am guessing it generates at least 1.8 V since the ATtiny13V runs on it. this is nice for a flashlight too

Jan 4, 2008. 9:10 PMRectifier says:

Wicked die! I would probably have gone for a 2d6 display though, as it's a bit more versatile for actual board game use. As many others said, would be nice to have a little more "instructable". Even a mention as to a bit of the theory behind operation, so another builder wouldn't have to design it from scratch (obviously it generates a random number when voltage is first applied, but what about the second shake while it's already on - is it detected on a I/O line? How is random seeding done?)

Jan 4, 2008. 7:49 PMDeLorean4905 says:

cool idea! finally, there's a solution to dice landing on an edge, lol. the wiring schematic would be nice though

Jan 4, 2008. 6:20 PMSpinWard says:

I agree, nice project. I'd just like to know how to make it!

Jan 4, 2008. 11:45 AMgmoon says:

You're making the rounds, my friend! (for those who haven't seen this before, it was featured on avrfreaks.net in Sept last year...) Very cool project, indeed!

Jan 4, 2008. 11:30 AMimonsei says:

OMG! this is the nerdiest geekiest thing i have ever seen! you, sir, are my new hero! as a programmer and rpg player this is the stuff my wet dreams are made of :D

Jan 4, 2008. 11:36 AMGorillazMiko says:

Nerdiest and geekiest, but still, one of the coolest things I've seen. Amazing Instructable, 3 thumbs up, sadly, I only have 2.

Jan 4, 2008. 10:55 AM!Andrew_Modder! says:

wow thats really cool! Just how do i make it :-(??. Also lol that would have made my day if you said "Thank you come again!" in the end x-D

Jan 4, 2008. 10:50 AMrickyd! says:

how do you make it?

Jan 4, 2008. 8:12 AMthadrien says:

Very great ! Bonus points for the video and the music: not all projects are so well presented ! And, the system of powering is clever !

Jan 4, 2008. 7:27 AM

thearchitect says:

Great project!.. Could you please share the schematics and the code, too? Really good job, I can see a commercial application there, easily!.. Good luck!.. and thanks for sharing!.. thearchitect.