Go Down

Topic: RGB led color select (Read 974 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.  Screw Shield for Mega/Due/Uno,  Bobuino with ATMega1284P, & other '328P & '1284P creations & offerings at  my website.

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.  Screw Shield for Mega/Due/Uno,  Bobuino with ATMega1284P, & other '328P & '1284P creations & offerings at  my website.

polhemic


Go Up
 


Please enter a valid email to subscribe

Confirm your email address

We need to confirm your email address.
To complete the subscription, please click the link in the email we just sent you.

Thank you for subscribing!

Arduino
via Egeo 16
Torino, 10131
Italy