Wind-up torch hand cranked, dynamo, LED -Amended-

Parts list

A white 5mm LED. I think it's 2000mcd, it came out of my junk box.
A red 3mm LED - high brightness. Optional. Lights when the capacitor is being charged by the dynamo.
A 1 Farad, 5.5 Volt capacitor.
A hand held crank dynamo. I got it at Jaycar electronics. I think the motor/gearbox from a simple toy car would probably work just as well.
It puts out about 5 Volts at top speed, so I thought it was a good idea to use a comparable capacitor.

Lots of patience. And coffee. And ciggies.


The switch stops the capacitor from discharging straight into the white LED, that would make it a hand-cranked light, and not a wind up, to use hands free, torch.

Step 1 The dynamo crank

This is the dynamo crank. Turn the handle on the side and the gears turn the dynamo, and through the magic of science, electricity comes out...

Comments

[Joelson Filipe]

will a normal toy motor really work??? im not sure.....
plz comment/reply

[LasVegas]

Your small LED is backward in the schematic.

[Wonko the sane]

The small LED has to be backwards. It's to stop the capacitor discharging back into the motor. It looks wrong, I know, but it does work.

[LasVegas]

That's what I mean. It has to have the cathode (flat side) on the positive side of the capacitor to allow charging of the capacitor and prevent discharge through the generator. If you follow the path of discharge with the switch off, you'll see that the schematic has both LEDs with the same polarity.

[LasVegas]

You built the circuit right. You just made a minor error on the schematic. The attached (corrected) schematic shows the charging path of current (blue) and the discharge path (red). As you can see, as in any diodes, current flows into the LED's cathode against the arrow. This is a carry-over of the pre-transistor belief that current flowed from positive to negitive.

[kanpur]

thanks and please launch the right schematic or instructables

[Wonko the sane]

Thanks. I stand corrected. I'm not too bad with a soldering iron, but my theory work is terrible. Appreciate the input.

[davidprosser]

Where can you get these capacitors!!! I can't find many suppliers in the UK, so if anyboady knows of any cos i really gotta get my hands on some (Or if anyone knows what electric appliances have these caps in). Or i think some USA company could ship one to me.....

[wizzywoo]

have you tried maplins or Radioshack altho i think raidio shack is american

[dean-101]

hey, you can get double layer 5.5V 1F Super caps for £3.68 on this site in the UK
www.maplin.co.uk . i got one and charged it via usb for 3 minutes and it kept an ultra birght blue LED on without a resistor for over 4 hours before going very dim but it was still on.
this is the link i got mine on http://www.maplin.co.uk/Module.aspx?ModuleNo=98185&criteria=5.5v%20&doy=5m3

[davidprosser]

Thankyou so much dean-101! i shall get one bought for me lol as its my birthday on the 24th! :) thanks

[dean-101]

no problem. if you are also loooking for cheap leds or resistors goto ebay and find a shop called "sure electronics" they sell 100 ultra bright LEDS with resistors for £10 and you can get blue, uv ,red ,green or white. they also sell Micro controllers, solar cells, laser, tools and everything to do with electronics very cheap.

[Derin]

+ for details - for mention of cigarettes

[InfamousKirch]

Uhm... what's the issue with mentioning cigs, it's one word in 10 pages of instructables ... @least he didn't dedicate a whole article on such an apparently offensive subject.

[geeklord]

Why isn't there any regulation??? Wreck your LED's.

[matroska]

Wait, tell me if I'm wrong, the dynamo is basically an electric motor that you turn so electricity is produced?

I really thought dynamo's were something totally different (if I'm right).

That means I can use any electric motor I have here and use it to power electronic thingys? That'd be cool (try dismantling an old matrix printer, LOTS of useful motors in there. ..too much in fact)

[djr6789]

it works on most dc motors but not sure about ac motors

[geeklord]

Ac motors have two coils not one coil and a permanant magnet, so no it would not work.

[shawon]

hey can i use a rechargeable battery instead of the super capacitor??? Super capacitor is not available in local market...

[Varun R]

can anyone tell me where to get super bright leds in india, specifically in bangalore? all we get are dim red ones like the one you,ve used in the charging indicator

[Artificial Intelligence]

Nice, how long does the LED stay lit on a capacitor charge?

[assasinzEX]

good job ure helpin me on my science project congratz to all helped u...wakakaka

[Wonko the sane]

I thought I was clever, making this. Then I found this - a wind up torch using a servo motor. I'm impressed. tearsoffire.org/twiki/bin/view/Projects/WindupFlashlight

[Mike060187]

yo... nice link for the servo led thin... its awesome =)

[electronicfreak22]

I made something like this only the crank was attached to a sooped up air hogs engine hooked up to co2. Its pretty cool and at top speed it can charge a lantern battery. I was going to post it but I forgot to take pics in the process.

[Crash2108]

In theory, could you wire it up so you spin the motor, then the motor starts spinning? Wouldn't that be just a plain, simple hookup with the capacitor?

[Wonko the sane]

Good to see someone's looked at the circuit/unit, and thought'I wonder if I could make this better...'. I've put up three more photos of the crank unit, and some more notes. I hope that helps. Because the motor runs 'backwards' to convention, I don't think you could wire it up. The circuit needs the LED, or a diode to stop the capacitor draining back into the dynamo, and making it run. It is funny to watch the crank handle turning on it's own, though. Kind of spooky... If the capacitor drains back into the dynamo, there's no power to light the white LED. And that defeats the purpose of the exercise.

[mycroftxxx]

I am not a electronics person, but have you looked at the diagrams of BEAM Robotics "Solar Engines"? They should work fairly well for powering dynamo-flashlights. If I remember correctly, the circuit uses a transistor and a diode to keep power from going to the source, and withholds power from the load until a certain voltage level has been met. Something along those lines should work here

[Ian01]

There are various types of solarengine.
http://solarbotics.net/library/circuits/se.html