Hand Cranked Flashlight

Whereas On Fri, 10 Oct 2003 01:42:46 -0700, Watson A.Name - "Watt Sun" scribbled: , I thus relpy:

What I have around, is a DC gearmotor form a battery powered store display. I hooked it up to a small radio and got that to work. Now to add a clock sprong to it. Perhaps I cold use the recoil spring from one of the parts chainsaws about.

------------------------------- Look here:

Uses a bipolar stepper, gear this up and put a rubber roller on it.

-Steve

Try with one of the better 525 or so nm InGaN superduper green LEDs. If that works, it may have some usefulness due to that wavelength being dozens of times more visible to night vision than red is. Even by photometric measure, Nichia green LEDs are more efficient than the most efficient 5 mm red ones, almost by a factor of 2 when moderately underpowered.

If the voltage is on the low side, see if a transformer helps (not guaranteed to help). Try for not too great a turns ratio with the lower side having a design AC voltage of at least 12 volts (maybe a small one with a 120/240V dual voltage primary, used as an autotransformer? Maybe a

If you get voltage a little above optimum (current compromised), try fullwave bridge rectifying with Schottkey diodes (preferably lower voltage) and filtering with at least a 100 uF capacitor across the LED (InGaN LEDs, with average current of a few mA or more, are usually more efficient with steady DC than pulsed DC).

- Don Klipstein ( snipped-for-privacy@misty.com)

I've got one of the below dynamo flash lights and have wondered how it would work if converted to work with LEDs.

Got a Q for you. I bought some LEDs from Hosfelt, one of them, the

I also bought some others: 25-366, 25-276, 25-502, 25-504. I was disappointed in these, especially the 10 mm 25-276. It throws a dark circle with four antennas on the wall, looks like a sputnik. It's the die pattern, but it shouldn't stay in focus all the way across the room. Have you ever seen such a LED?

I've never had a problem with the ones I've bought from Nichia. But I bought a few blue LEDs for under a dollar each from a distributor, and I'm not happy. I've had at least two of them start to go intermittent while handling 25 mA of current. They might blink or flicker a little every few minutes, or even worse, go off for awhile.

I ordered a hundred 3 mm white LEDs for $25 from a Hong Kong dealer, and will receive them in a week or so. That's 1/8 the price I paid for Nichias. I hope they're not as poor a quality as the blues I got. I'm just looking for feedback on others' experience with these low budget LEDs bought on Ebay.

In article , shb*NO*SPAM*@comporium.net mentioned...

You can buy replacement light bulbs with LEDs from companies, if you want to try it. See

I built my own by putting 3 LEDs with 33 ohm resistors in the base of a prefocus light bulb. But the new ones on the above web pages do not require a certain voltage, they have a circuit in the base that allows them to work with almost any flashlight. I'd like to get a few just to try them out.