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Cheap LED Flashlight!!!

Discussion in 'Electronic Repair' started by Brad Petria, Oct 31, 2003.

  1. Brad Petria

    Brad Petria Guest

    Hi,
    LED flashlights are expensive. I had a spare 2 D cell flashlight. I
    ordered two high output LEDs ($2.99 ea.) from Jameco Co. part # 217525CD
    (MCDP-3004C). I took a standard flashlight bulb and carefully removed the
    glass bulb. I wicked away the solder at the bottom exposing a hole. I bent, at
    right angle, the short negative leads of each LED and inserted the two LEDs in
    the bulb base. I soldered the positive leads at the base bottom and negative
    leads to the side. Now I have a flashlight that is bright enough for 98
    percent of what I use a flashlight for, and it draws about 18 ma!!!!!!

    Brad

    Tip for your old computer (reduce discard pollution too):

    If you can't sell your old computer, don't throw it away. Use it to backup
    your software by transferring files/folders from your new computer or laptop
    to it. I transferred my Windows folder and other stuff to my old computer
    using "PC Link", which I downloaded from www.simtel.net (cool site).

    http://www.simtel.net/pub/dl/52792.html (info or download)
     
  2. techforce

    techforce Guest

    Nice ingenuity. So the LED's are rated at 1.5VDC each, which means you had
    to put them in series inside the gutted bulb?
     
  3. Jim Yanik

    Jim Yanik Guest



    Actaully,he said he soldered them in parallel.
    "I soldered the positive leads at the base bottom and negative
    leads to the side."

    But he's running 3.6V(3.4-3.8 V) LEDs without any current limiting resistor
    on ~3V of battery,so he's not getting the full 3000mcd output,and not using
    the cells efficiently.
     
  4. Guest


    Just curious, how does the light compare to a normal flashlight?

    -Chris
     
  5. Some white LED's now come with internal current limiting and boost
    regulators.
    http://ledmuseum.home.att.net/starlite.htm
    http://www.sinounion.com.hk/NIGHT_PEARL_LED_BULB.pdf (About $7/ea).
    I doubt if the $3 Jameco LED's were this type. It would therefore
    need a series resistor, regulator or other current limiter. Two cells
    will not yield enough output to be useful. Three cells will fry the
    LED's.

    Comparison of various commerical LED flashlights:
    http://www.uwgb.edu/nevermab/led.htm

    LED FAQ's
    http://members.misty.com/don/ledx.html
    http://ledmuseum.home.att.net/ledleft.htm
    http://www.lightemittingdiodes.org


    Here's a do it thyself conversion of a Mini MagLite
    http://www.otherpower.com/otherpower_lighting_flashlites.html

    Flyback circuit for driving white LED with one battery cell.
    http://www.elecdesign.com/Articles/Index.cfm?ArticleID=3892
    I've built it and it works.
     
  6. uk-hamman

    uk-hamman Guest

    hi
    I have a single blue Led torch
    and it runs on 3v button cell i done a test the other day in a dark country
    lane
    i saw a ( nation speed limit road-sign) and then
    walked in the oposit direction shining my single led torch
    at it until i was not able to see it any more

    to be honest the road bent before this actually happened
    and i was 340-feet away from the sign ..and still lit

    i thought this was amazing , for such a small thing
    its not got any external lenses or maginifyers added to it
    nor is it got any direction or light deflection refelctors
    , sipmly a led and a battery in a little plastic keyfob


    any one want one , i can supply one for
    2.99p post paid to Uk only let me know
    limited stock

    de paul
     
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