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
zanfr6 years ago
you could lose the diodes and use a smaller "goldcap"
Gadre (author)  zanfr6 years ago
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
zanfr Gadre6 years ago
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...
static zanfr3 years ago
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 .
kenny7897 years ago
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?
static kenny7893 years ago
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
it makes AC current but, you use 4 diodes in the circuit to regulate the alternating currents.
it is so great
Myself7 years ago
That was a nice demonstratable, but isn't it supposed to be an instructable?
bears0 Myself5 years ago
Myself Myself7 years ago
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.)
Eirinn Myself6 years ago
I didn't know either and i thank you for posting that re-reply
zaphodikus6 years ago
I read your "Programming and Customizing the AVR micro" - nice project.
junits156 years ago
thats pretty cool
trekman7 years ago
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.
trekman7 years ago
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.
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.
dhoncave7 years ago
could it be hack?to the owners advantage? i still trust the traditional dice
iKill7 years ago
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?
Gadre (author)  iKill7 years ago
You can get neodymium magnets from www.amazingmagnets.com. Leds from Radioshack, yeah sure.
iKill Gadre7 years ago
so they dont sell magnets there... i can get stuff offline though i havent got a credit card
Michaelshas neo magnets if there is one near you , I think when I was last there they went for $4 or so
Gadre (author)  iKill7 years ago
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
Rectifier7 years ago
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?)
cool idea! finally, there's a solution to dice landing on an edge, lol. the wiring schematic would be nice though
SpinWard7 years ago
I agree, nice project. I'd just like to know how to make it!
gmoon7 years ago
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!
imonsei7 years ago
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
Nerdiest and geekiest, but still, one of the coolest things I've seen. Amazing Instructable, 3 thumbs up, sadly, I only have 2.
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
rickyd!7 years ago
how do you make it?
thadrien7 years ago
Very great ! Bonus points for the video and the music: not all projects are so well presented ! And, the system of powering is clever !
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.