Wiring an LED

[KoukiS14]

Sort of off topic a bit, but does anyone here know if I would wire an LED so that the anode is connected to positive, and the cathode would go to ground? I'm confusing myself. . I mean that makes sense, and would solve the problem of adding a pot to a circuit and screwing up anything after that part of it.

I want to wire it like this:from power -> variable resistor (pot) -> LED (packaged with the correct resistor) -> ground

[bmlawless]

Correct, cathode=negative, anode=positive.

[KoukiS14]

Thank you sir. . I kept thinking that if I wire this the way I wanted to (and I don't know what would drive me to do that), that the resistance would be dropped for the entire rest of the damned harness.

And as it turns out, it likely would've.

I'm copying a thread I saw on vwvortex to add ambient lighting. . I know, a bit ricey, but my friends have it and I find it nice to have at times. I found a place that should work.

[Qxxx4]

rule of thumb, most LED's have a longer leg, that longer leg is the negative end. Make sure you test the LED, supervise it for a long period of time to make sure the resistance doesnt get hot and melt things! Best bet is to get a protoboard and test your circuits there first, but if your not a big electronics nerd like me then im sure you dont have that stuff lol If your doing multiple LED's be very careful of your choice of connecting resistors in parallel or series. If your putting this in your car you definately dont want to see smoke coming from the circuit at 100km/h on the highway....yikesssss

good luck, and ps....LOVE the signiture pic

[bmlawless]

Best bet is to get a protoboard and test your circuits there first, but if your not a big electronics nerd like me then im sure you dont have that stuff lol

HEY! I have a protoboard and my mom says I'm cool.

[KoukiS14]

HEY! I have a protoboard and my mom says I'm cool.

From my professional opinion as a mod on NICO, I think you're cool

[KoukiS14]

rule of thumb, most LED's have a longer leg, that longer leg is the negative end. Make sure you test the LED, supervise it for a long period of time to make sure the resistance doesnt get hot and melt things! Best bet is to get a protoboard and test your circuits there first, but if your not a big electronics nerd like me then im sure you dont have that stuff lol If your doing multiple LED's be very careful of your choice of connecting resistors in parallel or series. If your putting this in your car you definately dont want to see smoke coming from the circuit at 100km/h on the highway....yikesssss

good luck, and ps....LOVE the signiture pic

ahh yeah that is true. . I'm not a 100% noob, I actually worked in Radio Shack and screwed around with parts I'd "borrow" from that job. . But I'm def. not an electrical engineer. The light I got is actually a 168 wedge bulb -- I figured it would be cleaner to wire, since the resistor is contained in the base. I can then add another resistor or pot to control the light if it ends up being too bright and ricey. There'll just be a single light, because I'm NOT a pro at this, and there def. would be fire if I tried to add two.

I don't know why the hell I think I need to do this, other than it seems useful on other vehicles I've driven and I have an overwhelming need to screw around with crap.

[Qxxx4]

good call, youll be fine if your just wiring one and you definately know what your talking about. Nothing wrong with making things better, even if it takes hours to do something simple, you have pride in your work and whatever you did is unique from other people. So get that solder iron nice n hot and work your magic!

[KoukiS14]

Whoa it turned out better than I thought it would. . I didn't take any pics 'cause I don't like documenting my failures

But I have a really bright LED that happens to fit flush with the cover in front of the mirror, three 330 ohm resistors to dim it a tad, and I figured out where to get power from (it turns off with the power save feature, but on with ignition -- I don't mind, but I may add a relay later).

[AlabamaDan]

So what exactly are you doing with the leds? I'd like to wire up a series of leds in the engine compartment for work lights. Anyone ever thought of that before?

[maik21]

for leds u can run a 220ohms 1/2 watt resistor from radioshack, it will work with ultra, super or normal bright leds.



i made this some days ago . theyre 40 super bright red leds.

if u had a protoboard, do this:

+12 volts ---- resistor 220ohms -------- ( led ) ----- ground

u can conect the led in the inverse polarity and if u do that, it wont bright.and if u do right, it will bright.

leds can damage if u dont use the right resistor. if the resistor is to low led will burn and if is to hight led wont bright .

maybe all this help u

[KoukiS14]

So what exactly are you doing with the leds? I'd like to wire up a series of leds in the engine compartment for work lights. Anyone ever thought of that before?

Just an ambient light that shines down on the console, like you'd find in some other cars. I sort of like the utility at night, but I also like how it looks. I was scared of it winding up ricey, but it aside from the bit of glare I have on the rearview, it looks stock. The glare isn't bothersome however, just used a wide-angle LED. The LED is flat and sits almost flush (it's actually made up of several tiny LEDs -- see pic).

Also, I only drilled a hole in the plastic cover in front of the mirror, so if I hated it I can just replace that part and nobody would know.

I'd love to have some under the hood - not a bad idear.

[KoukiS14]

for leds u can run a 220ohms 1/2 watt resistor from radioshack, it will work with ultra, super or normal bright leds.

[mg]http://img339.imageshack.us/img339/4703/ledscm0.jpg[/img]

i made this some days ago . theyre 40 super bright red leds.

if u had a protoboard, do this:

+12 volts ---- resistor 220ohms -------- ( led ) ----- ground

u can conect the led in the inverse polarity and if u do that, it wont bright.and if u do right, it will bright.

leds can damage if u dont use the right resistor. if the resistor is to low led will burn and if is to hight led wont bright .

maybe all this help u

Def helps, and I'm gonna buy a proto board. . part of the reason I did this at all is because I love d!ck' around with stuff, and learning about electronics. My QX4 is my protoboard. . haha

I figured the correct resistance, but instead of doing that I just used a 168 wedge bulb that accepts 12vdc, and already has a resistor built in. I then soldered on three 330 ohm 1/2 watt resistors to dim it a little. . and it did, a very little. . I may not have used the right ones, or I may not understand them correctly, but as it turns out the light output is perfect.

My only beef is that the light is on whenever the vehicle is. . I don't care about that so much if I could convince myself I won't be replacing the LED ever again. . haha. . I know the lifetime is pretty high, but to be safe I usually cut that span in half and make a worst-case assumption.

Whoa I have a better idea. . a photovoltaic switch. . while searching if such a thing exists, I figured out that a photo resistor may be the ticket. . anyone ever used one of these? I want one that just pretty much cuts the current unless it's dark / dusk out. I found this:http://www.radioshack.com/prod...earch

Anyone?

edit: http://www.acroname.com/howto/....html



god all this work just to do this? what the hell is wrong with me?

[KoukiS14]

interesting to note. . I made an assumption that red = + . . I ended up using a white wire for the sunroof switch to get power, and I grounded to red. . haha. . I couldn't comprehend what the hell I was doing. So in short, open your FSM before doing this unlike what I did. . it made total sense after doing that.

[maik21]

for the first image, R2 will be a led with a resistor as a package.

(+) ----photoresistor ---- resistor ---- led ----- (-)

with the second its the same thing.... R1 will be a resistor with a led as a package....

it will work, but u need to know whats the resistance in dark and whats in light because this is very important in the operation of led.... u can change 1kohm resistance shown in pic for a 220ohms resistance.

[KoukiS14]

for the first image, R2 will be a led with a resistor as a package.

(+) ----photoresistor ---- resistor ---- led ----- (-)

with the second its the same thing.... R1 will be a resistor with a led as a package....

it will work, but u need to know whats the resistance in dark and whats in light because this is very important in the operation of led.... u can change 1kohm resistance shown in pic for a 220ohms resistance.

Yeah the 2nd image is what I'd be using. . the 1st one depicts a state when the LED would be in the off position during darkness, the 2nd is the opposite of that. These depictions are identical to what I have wired and have working now, minus the photoresistor. I just need to add that, and in the correct resistance range -- but that part, I have NO clue how to determine. I'm trying to find specs on OEM auto-on headlight sensors, but to no avail.

I found that a variable photoresistor is available, but I can't find them for sale.

Thanks!!

[maik21]

photoresistores are cheap.. go to radioshack an buy some one. i understand now ur picture diagram ....dont replace what i told u replace because i had misinformation .... but after the v line, yea, u will need a resistor with a led. so go and get the photoresistor... there are 2 types... one that has high resistance in dark and the other is the opposite. if u dont have a multimeter u will need to do two configurations u found to know what will work . dont worry, u can burn nothing.

[KoukiS14]

photoresistores are cheap.. go to radioshack an buy some one. i understand now ur picture diagram ....dont replace what i told u replace because i had misinformation .... but after the v line, yea, u will need a resistor with a led. so go and get the photoresistor... there are 2 types... one that has high resistance in dark and the other is the opposite. if u dont have a multimeter u will need to do two configurations u found to know what will work . dont worry, u can burn nothing.

You're awesome!! Thanks -- I'll go pick some up and try it out. . It's interesting, because I'm worried about it not working right the first time, yet I spent the time taking it all apart and figuring this much of it out.

I do have a cheap digital multimeter, which has been absolutely invaluable over the years, and saved me a lot of time on this project.

[maik21]

some times u dont need a multimeter.. only need a bulb and this all u need.. in a car, its important to find voltaje + and voltaje - .... this can be found with a bulb. only wyhen u need to do an adjust to exact voltaje is when u need a multimeter. there are many tricks u can learn with time.