DIY LEDs

[Philip Lee]

u're right cameltree, but centre brake lights don't need a very wide angle anyway.

the reason i ask is i wonder if 90 Leds with 15mcd be bright enough? cos those are very cheap.......

ps. Panda, DIY a Led circuit from parts isn't that easy and you'll need to understand the basic physics. there are tons of info on the internet and once u've kinda understand, it's just a matter of solder the leds and resistors on the circuit board.

[crankshaft]

Guys, how d u actually calculate the resistor needed? are there any web that explains how to wire these leds n resistors?
Thanks guys

[TypeG]

LEDs on at nite

[TypeG]

u're right cameltree, but centre brake lights don't need a very wide angle anyway.

the reason i ask is i wonder if 90 Leds with 15mcd be bright enough? cos those are very cheap.......

ps. Panda, DIY a Led circuit from parts isn't that easy and you'll need to understand the basic physics. there are tons of info on the internet and once u've kinda understand, it's just a matter of solder the leds and resistors on the circuit board.

u are RIGHT as brake dun DO NOT need 90 angle at all. U can go Dicksmith and ask on their LED's mcd but I can tell you they are more than enough and cheap as u can see in the above pictures

[spoon fit]

not bad~

[DavidLing]

Guys, how d u actually calculate the resistor needed? are there any web that explains how to wire these leds n resistors?
Thanks guys

Basically, u can use this formular:
R = (E - V) / I

R = Resistecne
E = e.m.f (can say the voltage from the car)
V = Voltage (Voltage of the LED)
I = Current

e.g. if a LED is 2.3V 50mA (= 0.05A), and the emf is 12V
R = (12 - 2.3) / 0.05
R = 194 Ohm

But this formular only suitable for serial circuit in LED and Resistor:
------||------
|..................|
-{////}---@---

||: is the battery
{/////}: is the resistor
@: is the LED

So if u wanna put more then 1 LED, u can try to put this setting in parallel:

------||------
|..................|
-{////}---@---
|..................|
-{////}---@---
|..................|
-{////}---@---
|..................|
-{////}---@---
|..................|
-{////}---@---
|..................|
-{////}---@---

In this case, all the resistors are with the same resistance (ohm), and u no need to care about how many LEDs that u are using!

Actually, u also can use only 1 resistor with many LEDs! But u need to:
how the Voltage & Current in serial and parallel circuit;
understand the Ohm Rule; and
how many LEDs that u are using
In this case, the circuit will be more cmplicated!!

Ohm rules:
V=IR

You can have a look this website, however, it is in Chinese:
http://www.phy.cuhk.edu.hk/phyworld/...e2/ppframe.htm

[spoon fit]

You can have a look this website, however, it is in Chinese:
http://www.phy.cuhk.edu.hk/phyworld/...e2/ppframe.htm

thx!

[DavidLing]

thx!

the website is about the basic phy. only! not telling u how to connect a LED!
But u can consider a LED as a resistor as well, then u will more understand how to calculate!

Actually, i found another website is telling how to light up a LED:
http://www.twoengineers.com/Richard/leds.html

[panda[cRx]]

ps. Panda, DIY a Led circuit from parts isn't that easy and you'll need to understand the basic physics. there are tons of info on the internet and once u've kinda understand, it's just a matter of solder the leds and resistors on the circuit board.

cool, i might get my mate to do it, he's done similar things to pc's and xbox's lol