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Topic # 29725 16-Jan-2009 18:01
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OK I need some help from someone that knows a bit about electrical things. I want to setup a full color LED on my media centre using the LEDSdriver software. I already set it up using the power LED to tell me when it is recording one or two things.

I tried to buy the parts myself from Jaycar and test it out using a 9 volt battery as per a suggestion from the software writer however that resulted in one dead LED (and the arid smell of burnt things) Frown

This is the page with the instructions

http://www.degroeneknop.nl/forum/index.php/topic,4809.0.html

Now I purchased from Jaycar the following
LED 5mm RGB LED (Red/Green/Blue) STOCK-CODE:ZD0270 which is now dead
22Kohm 1/2 Watt 1% Metal Film Resistors – Pk.8    STOCK-CODE:RR0604
18Kohm 1 Watt 5% Carbon Film Resistor - Pk. 2 STOCK-CODE:RR2804

My understanding was that I would be safe applying voltage from the 9 volt battery directly to the LED but that was obviously wrong at least with the LED I purchased.

So what I need is some help on where I could get a full color LED from or as a fall back 3 colour like the one above that is correct for the application.
Also I am not really sure if the resisters I purchased are correct as the instructions are a little vague at least for someone like me.

I am quite comfortable soldering and have already sorted out a plug and wiring to fit the internal com port header on the media centre mother board but I am stuck on what to buy and where from.

Hoping someone here can help.







Media centre PC - Case Silverstone LC16M with 2 X 80mm AcoustiFan DustPROOF, MOBO Gigabyte MA785GT-UD3H, CPU AMD X2 240 under volted, RAM 4 Gig DDR3 1033, HDD 120Gig System/512Gig data, Tuners 2 X Hauppauge HVR-3000, 1 X HVR-2200, Video Palit GT 220, Sound Realtek 886A HD (onboard), Optical LiteOn DH-401S Blue-ray using TotalMedia Theatre Power Corsair VX Series, 450W ATX PSU OS Windows 7 x64

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  Reply # 190037 16-Jan-2009 18:33
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LED's all require a resistor unless they are rated at 12v. You have obviously leant what happens if you don't use a resistor!

The circuit probably should fine - you did look at the specs sheet and see that the cathode (-) is the longest pin? Using a 22Kohm resistor wired to the 3 annodes should be fine

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  Reply # 190177 17-Jan-2009 13:51
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22k is way overkill for a LED on 12v - 1k is closer to what is normally used.

22k would give half a milliamp or so. - not very much light at all

calculator is here

http://led.linear1.org/1led.wiz

I wouldnt go above about 30mA total on those 3 colour leds since the package is still pretty poor at dissipating heat.

Nice abuse of a serial port however. Not sure what current you will get from one tho, and I would forget trying a USB com port since they barely make the needed rs232 voltage levels when nothing is plugged in from my experiances with them.




Richard rich.ms



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  Reply # 190206 17-Jan-2009 18:01
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OK got it all up and running. Talked to a guy at Jaycar who worked out the required resistor for that LED. Worked out as a 510 Ohm for the red and 450 Ohm for the other two colors.

Works great. I now have a power light that shows blue for no recordings (basicaly making it a power light). It then turns green if there is one recording and red for two recordings.

Was a pitty I could not source a full color LED as that would have opened the options up but still wrapped with the result.







Media centre PC - Case Silverstone LC16M with 2 X 80mm AcoustiFan DustPROOF, MOBO Gigabyte MA785GT-UD3H, CPU AMD X2 240 under volted, RAM 4 Gig DDR3 1033, HDD 120Gig System/512Gig data, Tuners 2 X Hauppauge HVR-3000, 1 X HVR-2200, Video Palit GT 220, Sound Realtek 886A HD (onboard), Optical LiteOn DH-401S Blue-ray using TotalMedia Theatre Power Corsair VX Series, 450W ATX PSU OS Windows 7 x64

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