basic question on " microcontroller for LED"

[kaitlyn]

question for microcontroller

Hey friends,

Do someone know when microcontroller was used for LED?
it started from 1997? or even more earlier?
I can not find any information since it's too old.

Please help me!!! Looking forward

Cheers,
Kaitlyn

 

[alec82]

hi
explain more your question

 

[Buriedcode]

Hi,

As Alec82 pointed out, its a pretty vague question What do you mean by 'LED' exactly? Because microcontrollers have been driving LED's way before '97. Perhaps you mean LED displays, such as 7-segment displays, or dot matrix? More information would be helpful.

Buriedcode.

 

[kaitlyn]

yes,
you know microcontroller can be used to control the LEDs to give us red, green, blue light etc..

There are a lot of information on the internet after 2000. my question is when this control meathod came up? for sure it must be before 2000. But how can i find some information in 1990--1999?

Cheers,
Kaitlyn

 

[Buriedcode]

yes,
you know microcontroller can be used to control the LEDs to give us red, green, blue light etc..

Well, the colour of an LED depends on the the LED die/material itself, not whats driving it. But do you mean 'RGB' led's? (red, green, blue dies in one package) Or even RGB led arrays (seperate red, green, blue LED's next to each other)? With each 'colour' having seperate control, to allow mixing of intensities, to produce virtually any colour you want.

There are a lot of information on the internet after 2000. my question is when this control meathod came up? for sure it must be before 2000. But how can i find some information in 1990--1999?

Well, RGB LED's kicked off fairly recently (2002/3?), mainly becase manufacturers started putting R,G and B led's in one package...all of which were 'intensity matched' so that they gave pure white light when driven with the same current.

However, before they were available as one 'device', seperate LED's in individual packages were used, which of course required blue LED's (you need R, G, and B to make 'any colour' via mixing). These became available back in the 90's, with the first ones being pretty crap, low intensity, and very expensive...as you can probably tell, they are everywhere nowdays, thanks to better and cheaper manufacturing methods. You might not find any information about RGB arrays (or the microcontroller designs that drive them) before 1999, because blue led's were fairly new, and didn't match up to the intensity of red/green LED's.

As for microcontrollers driving LED's? PWM (Pulse width modulation) is used. you can google that. And as far as I know, that method has existed for ages, and not just for LED's, for any illumination or motor control. It is just used to control the apparent intensity of an LED (any colour). RGB colour mixing with microcontrollers just uses 3 PWM's for the intensity of each LED, controlled by a single 9/10-bit number. I've done it with 8-bit PWM, so the number of possibilities is 24 bit (3 x 8 bit numbers). A quick browse of wikipedia for 'RGB array', RGB Led's, and 'PWM' might prove useful.


At least, thats what I 'assumed' you meant. I could be waay off here, I'm still unsure what your question is exactly.

Just another rant,

BuriedCode.

 

[kaitlyn]

wowwww! you really help me a lot!!!That's exactly what i want to know
Thank you very very much!!!

Cheers,
Kaitlyn

 

[Buriedcode]

You are most welcome Google is handy, but not so handy if you don't know exactly what you're looking for. I hope that steered you in the right direction! You might want to confirm the times and dates about the first blue led, RGB led, and PWM in microcontrollers.

Buriedcode.