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G8MNY > TECH 22.11.11 09:44l 86 Lines 3218 Bytes #999 (0) @ WW
BID : 17844_GB7CIP
Read: GUEST
Subj: Cheap Battery/12v LED Light
Path: IZ3LSV<IV3SCP<IW0QNL<HB9ON<IW8PGT<CX2SA<UA6ADV<GB7CIP
Sent: 111121/2354Z @:GB7CIP.#32.GBR.EU #:17844 [Caterham] $:17844_GB7CIP
From: G8MNY@GB7CIP.#32.GBR.EU
To : TECH@WW
By G8MNY (Updated May 10)
(8 Bit ASCII graphics use code page 437 or 850, Terminal Font)
Recently I discovered the "99p shop" discount shops was selling twin packs of
4.5V self contained 3 LED battery lights for 99p (~1.5eu/$). Is this less than
parts cost? I have seen theses lamps in 3 packs for far more in other shops!
Inside there is a proper locking "tack" switch, 3 bright LEDs, flexible
reflecting housing button spring, & stick up 3x AAA in the round battery box.
clear press cover
_..--ÄÄÄ--.._ n = LED
/~~~~Ù À~~~~\ Û
³ÃÄÄÄ ~\.n./~º~\.n./~ ÄÄÄ´³
³³(bat)__Û__±±±__Û__(bat)³³ ~\ = Spring Reflector
|³.......................³|
=========================== º = Switch
Bernet ~~~~~~~~~~ ±±±
Base Sticky ___ = PCB
White LEDs are about 3V, so a 10R is in series with a 3 paralleled LEDs on 4.5V
to limit the current.
+ÚÄÄo\oÄÄÄ10RÄÄÄÂÄÄÄÄÂÄÄÄÄ¿
_³_ ³ ³ ³
_Ü_ _³_ _³_ _³_
_Ü_ 3x LED ð\_/ \_/ \_/
Ü AAA ³ ³ ³
³ ³ ³ ³
ÀÄÄÄÄÄÄÄÄÄÄÄÄÄÄÁÄÄÄÄÁÄÄÄÄÙ
The lights are quite useful as they are. They draw some 90mA from the 3x AAA
cells. But I found the double sided sticky quite poor. So I intend to screw the
base in place & attach the body.
Modification for 12V
This is a fiddly job! The case is lightly glued around the edge & a small screw
driver inserted between the cover & black inner & worked around will crack the
glue, & separate 2 undamaged parts.
Putting the LEDs in series & replacing the 10R with a small 100R is needed for
the 30mA @ 13.8V Max.
ÚÄÄo\oÄÄÄ100RÄÄÄÄÄÄÄÄÄÄÄÄÄÄ¿
³ ÚÄÄ¿ ÚÄÄ¿ ³
+12V ÄÙ _³_ ³ _³_ ³ _³_
LED ð\_/ ³ \_/ ³ \_/
³ ÀÄÄÙ ÀÄÄÙ
0V Ä¿ ³
ÀÄÄÄÄÄÄÄÄÄÄÄÄÄÄÙ
I cut 3 of the paralleling tracks & use fine wire to remake the circuit. I
found the modern lead fee solder they had used really poor, & not supporting
the components at all well, so I remade all the connections with lead solder!
External connection is made through the base & soldered on to the battery clips
(good solder!). In a car the earth can be the mounting screw.
MAP LIGHT
Using some strip board pressed into the chrome holder, I replaced a hot dim
power hungry lensed lamp with 6 LEDs. I cut away the copper track away at the
edge to make sure there was no shorting to the case.
__________________ _____________________
ÀÄÄ¿ ÚÄÄÙ ÀÄÄ¿ ÚÄÄÙ
(o)_.--ÄÄÄ'''~~³\ (o)_.--ÄÄÄ'''~~ o o 6 LEDs
(_)_/\/\/Bulb ³ | (_)_ Rs ||LEDS o o
~ÄÄ---...__³/ ~ÄÄ---...__ o o
As this is used for illuminating my radio while /M (14V battery), I used 2 120R
as the series Rs, one for each chain of 3 LEDs.
12V SAFETY
Make sure the 12V is fused (e.g. 1A) & there is no fire risk from trapped wires
etc.
If your find the light is too directional, just lightly scratch LED lens heads
or lamp cover to defuse more of the light.
Why Don't U send an interesting bul?
73 de John G8MNY @ GB7CIP
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