2 replies to this topic

[irda]

Hi, I'm interested to controlling three RGB LEDs with netduino, I understand that I need 9 PWM outputs but netduino only have 4. Is it possible to extend to 9 PWM outputs or control 3 RGB LEDs with netduino? How? thanks

[Nevyn]

Hi, I'm interested to controlling three RGB LEDs with netduino, I understand that I need 9 PWM outputs but netduino only have 4. Is it possible to extend to 9 PWM outputs or control 3 RGB LEDs with netduino? How?

I think you will need a driver chip. I played around with the TLC5940 last year. One of these should allow you to control upto 5 RGB LEDs per chip but would need to look at providing some additonal circuitry (clock, counters/dividers).

Hope this helps,
Mark

[Bainesbunch]

Hi You can always use 3 other IO lines to connect to the common cathodes of the RGB LEDS pulling them to gound one at a time and multiplex the PWM outputs. You would only ever achive a miaxmum of 30% duty cycle on any LED but that may do you. Cheers Pete.