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G8MNY > TECH 26.12.09 00:56l 78 Lines 4049 Bytes #999 (0) @ WW
BID : 45668_GB7CIP
Read: GUEST
Subj: Windup Torch info
Path: IZ3LSV<IW0QNL<OK4PEN<SV1CMG<DK0WUE<7M3TJZ<CT1EJC<ED1ZAC<GB7CIP
Sent: 091225/2332Z @:GB7CIP.#32.GBR.EU #:45668 [Caterham] $:45668_GB7CIP
From: G8MNY@GB7CIP.#32.GBR.EU
To : TECH@WW
By G8MNY (Updated Dec 05)
(8 Bit ASCII Graphics use code page 437 or 850)
Not being one to leave a new toy unexamined, here is info I reverse engineered
from one of these fairly cheap LED torches.
o all
ÚÄÄÄÄÂÄÄÄÂÄÄÄÄÄÄÂÄÄÄÄÄÄ¿ oÄÄÄÄÄÄÄÄÄÄÄÄÄÂÄÄÄÄÄ¿
_³_ _³_ ³ R4 ³ ÚÄÄ>o off D2_³_ _³_D3
/_\ /_\ ³ 470ê ³/ ³ oÄÄÄ¿ D1 \_/ \_/
ÚÄÄÄÄÄÄ´ ³ ³+ ÃÄÄÄÄ´T1 ³ one ÀÄ´>ÃÄÄÄÄÄ´ ³1N5817
MOTOR AS ³D4-7³ === _³_ ³\___³ ÚÄÄÄÄÄ)ÄÄÄÄÄ´
GENERATOR ³ ³ ³C1 /_\' e ³ R1 R2 R3
ÀÄÄÄÄÄÄ)ÄÄÄÄ´ ³47uF ³DW __³__ 68ê 68ê 68ê
_³_ _³_ ³25V ³5.2V ÜÜÜ _³_ _³_ _³_
/_\ /_\ ³ ³ LIR³ ð\_/ ð\_/ ð\_/
³ ³ ³ ³ 2032³ LED1 ³ LED2³ LED3³
ÀÄÄÄÄÁÄÄÄÁÄÄÄÄÄÄÁÄÄÄÄÄÄÄÄÄÁÄÄÄÄÄÄÄÄÄÄÄÁÄÄÄÄÄÁÄÄÄÄÄÙ
HOW IT WORKS
A small motor spin from a 4 gear chain from the crank handle. The motor
generates over 5V & feeds a silicon bridge rectifier D4-7, which I guess is
there just in case the rotation is reversed. This DC feeds C1 & powers up the
zener DW to make T1 conduct current into the 3.6V Lithium Iron rechargeable
button cell until the cell if fully charged & the voltage rises to cut off the
current from T1's emitter. With normal winding speed this takes only 30-60
seconds.
A 4 way push action rotary switch powers the LEDs, either one or all 3 through
low voltage drop steering diodes D1-3 to a current limiting resistor to the
2.6 - 3V V Hyper-Bright white LEDs. The battery can light all 3 LEDs for more
than 30 mins on one charge. The light output is quite feeble compared to a
normal torch of the same size, but it is quite enough to read at night etc.
MY IMPROVEMENTS
ÚÄÄÄÄÄÂÄÄÄÄÄÂÄÄÄÄÄÄÄÂÄÄÄÄÄÄ¿ o one
³ ³ _³_ ³ ³ oÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄ¿
1N5817_³_ ³ =\_/LED 1k ³ ÚÄÄ>o all ³
/_\ ³ ³GREEN ³ ³/ ³ oÄÄÄÄÄÄÂÄÄÄÄÄÄÄÄÄ¿ ³
+³ ³+ ³ ÃÄÄÄÄ´T1 ³ ³e ³/e e\³
MOTOR AS === 220ê _³_ ³\____³ ³/ ÚÄÄ´ PNP ÃÄÄ¿
GENERATOR ³C1 ³ /_\' e ³ ÚÄÄ´PNP 100k ³\ ____/³ ³
TURNED 1 ³47uF ³ ³ __³__ 47k ³\ ³ ³ 100k
WAY ONLY ³25V _³_ ³4.7V ÜÜÜ ³ ÃÄÄÄÄ)ÄÄÄÄ)ÄÄÄÄ¿ ³
-³ ³ /_\' ³ LIR³ ³ _³_ ³ _³_ _³_ ³
³ ³ ³5V ³ 2032³ ³ ð\_/ ³ ð\_/ ð\_/ ³
ÀÄÄÄÄÄÁÄÄÄÄÄÁÄÄÄÄÄÄÄÁÄÄÄÄÄÄÄÄÄÄÁÄÄÄÄÄÁÄÄÄÄÁÄÄÄÄÁÄÄÄÄÁÄÄÄÄÁÄÄÄÙ
1/ Constant current to LEDs. Almost constant LED current until the battery
fails with 3 small PNP transistors. The 47k/100k values on the bases depends
on the PNP transistor gain to give the right LED currents of 10mA MAX,
values in the range 22k to 220k may be needed.
Replace the 3 LED 68ê with wire links & replace the 3 Schotky diodes with
the PNPs mounted right down for minimum headroom, add the base Rs to nearby
grounds.
2/ Bridge losses removed. Replace the 4 silicon diodes with 1 of the 1N5817
diodes. Make sure the generator is wired up for your favoured rotation
direction. Swap 1 of the +ve rail diode for the 1N5817 & solder the motor
-ve to the -ve rail. Note the free unloaded generator action if reverse
wound.
3/ Battery Charged LED. First I found the original zener diode to be too high a
voltage & the regulator never came in as the new 3.6V battery would not
reach 4.5V to stop the current flow, so I replace the zener with a 4.7V one
selected on test & also doubled the supply R to 1k. Then adding a GREEN LED
with a 220ê to monitor the generator voltage with the original zener.
In use it lights up when the handle is cranked hard & then easily when the
battery is charged.
Why don't you write an interesting bul?
73 De John, G8MNY @ GB7CIP
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