dual color leds

[mollick2]

thats what i thought, i think i'll forget the indicators then.

[Jim Beam]

you could just use a single color LED run a small circuit in parralel with the fan circuit. or you could get real fancy and use a micro controller. easy to programm and learn about here

[Spawn-Inc]

you could just use a single color LED run a small circuit in parralel with the fan circuit. or you could get real fancy and use a micro controller. easy to programm and learn about here

no that won't work, the led will always be on. but the micro controller might work.

[Jim Beam]

if you used a larger resistor so it was barely on at 5v and real bright at 12 v it might work then again I could be wrong

[xmastree]

Just to answer the unanswered question here, what makes them different colours...

It's simple really, they are made from different chemicals, which emit different coloured light.

[xmastree]

thanks for your help, i was planning on using the dual color led's as a indicator so for the fan being on low or high, but i don't think it would be too simple.

Something which hasn't been mentioned (unless I missed it) is two colour LEDs with only two wires. These are made from two chips, wired in inverse parallel. The colour is determined by which way round you connect them.

It wouldn't be too difficult to indicate your fan speed, but you would need some electronics to drive the LED.

[calumc]

if i under stand what you're trying to do properly (which i think i do)
i saw a guide on building a dual voltage fanbus using dual color leds as indicators but unfortunately i cant seem to find it. i did get this one using single color leds:
http://www.metku.net/index.html?path...ybus/index_eng
and you'll just have to modify it to suit your needs.
i'm not sure what the correct name for the switches you'll need is but it would be the ones that stop in the middle so you can use that as off.
as for the leds you'll be doing it just as in the diagram but you'll be cannecting the other lead to the 5v lead:

i think thats right but someone please correct me if i'm wrong

[mollick2]

edit: nvm i get it, read that link through, makes since now.

i don't get your changes though

[calumc]

thats prob not right what i did but what i was trying to do was put one colour on the 12v and one on the 7v. i did see a guide for it but i cant find it

[Spawn-Inc]

if i under stand what you're trying to do properly (which i think i do)
i saw a guide on building a dual voltage fanbus using dual color leds as indicators but unfortunately i cant seem to find it. i did get this one using single color leds:
http://www.metku.net/index.html?path...ybus/index_eng
and you'll just have to modify it to suit your needs.
i'm not sure what the correct name for the switches you'll need is but it would be the ones that stop in the middle so you can use that as off.
as for the leds you'll be doing it just as in the diagram but you'll be cannecting the other lead to the 5v lead:

i think thats right but someone please correct me if i'm wrong

that would work for 12v but not 5v. the 5v will never turn on the way its wired.

ok so i just talked to my dad and there is a switch that will do what you want. its called a Double Pull Double Throw (DPDT),on-off-on toggle switch

so now that i know the switch exists you would wire it up like this.

i used the 3 prong style LED from here, good place BTW, and used this LED calculator for the resistors. its hookup up for 5v red (less speed less cooling) and blue for 12v (faster speed better cooling) i'm not sure if this will work but here is a link to a search from a online store that sells the switchs. make sure when you look for a switch if you go through with this project that you look for a DPDT, on-off-on switch not a on-none-on.

so to answer your question finally yes, you can do it and thats how!


EDIT: this won't work after all, i'm working to see if it can. ok so i think i have it yet again but i'm going to work on it tomorrow or rather later today.