Re: LED's for dummies
- From: jasen <jasen@xxxxxxxxxxx>
- Date: 17 Aug 2006 11:04:34 GMT
On 2006-08-16, hepstyle@xxxxxxxxx <hepstyle@xxxxxxxxx> wrote:
I'm apparently an incredible dummy, because I can't wrap my mind around
this concept yet. So I'm sorry to ask such a rudimentary set of
questions.
I have been given a bowling pin. I am supposed to take this bowling
pina dn turn it into a work of art which will be auctioned off for a
local charity. My idea as a budding electronics hobbyist is to
basically decoupage the pin and then install a bunch of LED's driven by
a wall wart.
So I will cut the pin in half at its widest point and hollow out the
inside as much as I can so that the electronics will fit in there, then
I will drill holes or wiring and try to place the LEDs in little
recesses that I will create.
there won't be any bulky electronics
if you can drill it from the base up the centre you may be able to do it all
from the bottom, start with a 1" (or larger) spade bit and hollow out the
bottom half then switch to a 0.5" and go up further
ANYWAY, I will be using 18-24 LEDs of various colors. Here is a list
(i'd be using 3-4 of each color):
more would be better...
Blue - 3.6V, 20mA
Orange - 1.7V, 20mA
Amber - 1.7V, 20mA
Green - 3.3V, 20mA
Red - 2.3V, 20mA
Sea Green - 3.3V, 20mA
My first problem is that I don't know for sure if those voltage specs
are just the voltage required to power the diode or if it is a
measurement of the voltage drop, or even if there is a difference
between the two.
it's basically the same thing.
But since the current for all of them is the same, I considered wiring
them in series. The problem there is that I was hoping to use a 9V,
500mA wall wart that I already have, and if those voltages are voltage
drops, I can't wire too many at a time.
yup. if you can, get a 12v or 24v wall-wart,
So clearly I have to use a combination of parallel and series circuits
in order to control the current while keeping the voltage under, say
7.2 volts. And I know that I will have to incorporate resistors
somewhere along the line. But that's it. I can't make it to the next
step. I'm not sure how I should distribute the LEDs so as to create
the most efficient circuit.
efficiency isn't real important. there's not enough power
there to start a fire or anything.
if the wall-wart is 9V regulated:
two blues 7.2V use resistor 91 ohms (should be 90)
a green and two oranges, 6.9V use resistor 110 ohms (105)
a sea green and two ambers, 6.9V 110 ohms (105)
three reds, 6.9V 110 ohms (105)
two greens 6.6V 120 ohms (120)
all those will be close enough.
I'm not sure where to put the resistors.
I want to draw a wiring diagram, of course, but I can't visualize this
for some reason.
hook the leds together in series (head to tail) and at one end put
(+) ---/\/\/\--->|--->|--->|---- (-)
use heatshrink tubing to insulate the connections.
the resistor. user oneresistor for each series group of leds
(+) ---/\/\/\--->|--->|--->|---- (-)
(+) ---/\/\/\--->|--->|--->|---- (-)
(+) ---/\/\/\--->|--->|--->|---- (-)
(+) ---/\/\/\--->|--->|--->|---- (-)
(+) ---/\/\/\--->|--->|--->|---- (-)
if you thread the wires into the holes first and then attach the LEDs that
may give the tidiest result. "wirewrap" wire is made for this sort of thing.
you can grind the flange off the LEDs to make them fit drilled recesses better
a sanding disk is good for this.
you'll need to be sure to connect them the right way round.
Bye.
Jasen
.
- References:
- LED's for dummies
- From: hepstyle
- LED's for dummies
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