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Topic: RGB led color select (Read 887 times) previous topic - next topic

ammygo

hi, I have RGB led and I want to change colors example to yellow or white. how can I do it? thanks.

CrossRoads

You need to be able to change how 'on' each LED is, the blend determines the color seen.
Simple way is 3 pots, with a series resistor so that you don't accidentally exceed the ~20mA current thru any LED.
More complicated is 3 PWMs from arduino driving the 3 LEDs, with frequency selected by reading 3 puts, some pushbutton, supplied via serial messages, etc.
Designing & building electrical circuits for over 25 years. Check out the ATMega1284P based Bobuino and other '328P & '1284P creations & offerings at  www.crossroadsfencing.com/BobuinoRev17.
Arduino for Teens available at Amazon.com.

Grumpy_Mike

Often it looks better if the light is diffused. If they are in a clear package then a light rub with sand paper will make the colours blend together so much better.

CrossRoads

ammygo PM'd me that he wants to make an 8x8 RGB LED table.

I wrote back:

Well, that's a lot more work than just 1 RGB LED!
That is 64, so you will need to control  3 x 64 = 192 signals.
Do some searching for TLC5940 (I think that is the part #).
It has 16 outputs, each output can have a PWM level assigned so you can set the brightness of each LED to change the color of each square.
You will need 192/16 = 12 pf them. I have not used them myself, but I  can help you figure out how to control them.
Post this question as a new thread so that others who have used this part can help with software questions.
Designing & building electrical circuits for over 25 years. Check out the ATMega1284P based Bobuino and other '328P & '1284P creations & offerings at  www.crossroadsfencing.com/BobuinoRev17.
Arduino for Teens available at Amazon.com.

polhemic


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