# RGB Led strips - controlling color and brightness independently **URL:** \ **Category:** General Electronics\ **Created:** [November 23, 2015, 2:15pm UTC](https://forum.arduino.cc/t/rgb-led-strips-controlling-color-and-brightness-independently/348393 "2015-11-23T14:15:30Z")\ **Posts on this page:** 4\ **Page:** 1
**Author:** ![anon71843352](https://avatars.discourse-cdn.com/v4/letter/a/bbe5ce/32.png) [@anon71843352](https://forum.arduino.cc/u/anon71843352)\ **Post date:** [November 23, 2015, 2:15pm UTC](https://forum.arduino.cc/t/rgb-led-strips-controlling-color-and-brightness-independently/348393/1 "2015-11-23T14:15:30Z")
Hello everybody! for a project I'm working on I want to control individually the brightness 12 RGB LED strips, for example turning on one at a time in a given order. When the LEDs are not on they should be actually half brightness, so I think I have to exclude the use of relays and go with transistors. I also need to control their color, but that needs to be the same for all of them, so it seems more efficent/elegant/clean to me to use 3 transistors/pins on the arduino for the RGB values and 12 for the brightness(es), rather than using 12 + 3 = 36 transistors. Is it possible to control with just 3 transistors on the RGB lines of the LEDS and then have another transistor on each + line of the LEDS, or that would create problems? Of course picking transistors with the appropriate power rating. If it's not clear I'll try to make a schematic. I have some experience about Arduino programming, but when it comes to electronics I'm always afraid to make a giant mess 🙄 Thank you everyone ---
**Author:** ![mrsummitville](https://avatars.discourse-cdn.com/v4/letter/m/9fc29f/32.png) [@mrsummitville](https://forum.arduino.cc/u/mrsummitville)\ **Post date:** [November 23, 2015, 2:49pm UTC](https://forum.arduino.cc/t/rgb-led-strips-controlling-color-and-brightness-independently/348393/2 "2015-11-23T14:49:05Z")
> andreaefferao: > Hello everybody! > > for a project I'm working on I want to control individually the brightness 12 RGB LED strips, for example turning on one at a time in a given order. When the LEDs are not on they should be actually half brightness, so I think I have to exclude the use of relays and go with transistors. > > I also need to control their color, but that needs to be the same for all of them, so it seems more efficent/elegant/clean to me to use 3 transistors/pins on the arduino for the RGB values and 12 for the brightness(es), rather than using 12 + 3 = 36 transistors. > > Is it possible to control with just 3 transistors on the RGB lines of the LEDS and then have another transistor on each + line of the LEDS, or that would create problems? > > Of course picking transistors with the appropriate power rating. > > If it's not clear I'll try to make a schematic. > > I have some experience about Arduino programming, but when it comes to electronics I'm always afraid to make a giant mess 🙄 > > Thank you everyone **RE: Is it possible to control with just 3 transistors on the RGB lines of the LEDS and then have another transistor on each + line of the LEDS, or that would create problems?** **If it's not clear I'll try to make a schematic.** You are correct , you will need to draw a schematic. Not just for us, but for yourself. [LED Shield](https://www.tindie.com/products/Conceptinetics/6-channel-led-shield-for-arduino-035-07-1a/) [MOSFET](https://learn.adafruit.com/rgb-led-strips/usage) ---
**Author:** ![CrossRoads](https://dub1.discourse-cdn.com/arduino/user_avatar/forum.arduino.cc/crossroads/32/214033_2.png) [@CrossRoads](https://forum.arduino.cc/u/CrossRoads)\ **Post date:** [November 23, 2015, 3:22pm UTC](https://forum.arduino.cc/t/rgb-led-strips-controlling-color-and-brightness-independently/348393/3 "2015-11-23T15:22:34Z")
So you'll have say P-channel MOSFET sourcing current to the + pin, and 3 N-channel MOSFET sinking current from the 3 - pins, with PWM going on both ends, + for brightness and - for color mixing? Could work I suppose, may get odd flickering on something from the 2 PWMs interacting with each other. I think that would be less likely if you just reduced the N-channel PWM level by 1/3 or 1/2 or whatever appears most pleasing when you want it dimmer. Easy enough to try - set up 3 strips with 3 transistors and see how it looks. AOI514 from digikey works well. I have 32 of them on a board for driving LED strips: [http://www.crossroadsfencing.com/BobuinoRev17/](http://www.crossroadsfencing.com/BobuinoRev17/) Here's a clip with 8 LED strips fading up & down. [![](https://europe1.discourse-cdn.com/arduino/original/4X/9/3/3/933871f96a85523cd675b9541af5853eb6197f22.jpeg "Arduino Power!") ](https://www.youtube.com/watch?v=hAVf1D1L-7c) Can use shiftPWM library to control LED colors, [http://www.elcojacobs.com/shiftpwm/](http://www.elcojacobs.com/shiftpwm/) and add PWM to 74HC595 OE/ for overall brightness too. ![](https://europe1.discourse-cdn.com/arduino/original/3X/c/7/c7d9dbcaeebfc93c5bb14e30792166bf660c60de.jpeg) ---
**Author:** ![system](https://dub1.discourse-cdn.com/arduino/user_avatar/forum.arduino.cc/system/32/1140315_2.png) [@system](https://forum.arduino.cc/u/system)\ **Post date:** [May 6, 2021, 1:49am UTC](https://forum.arduino.cc/t/rgb-led-strips-controlling-color-and-brightness-independently/348393/4 "2021-05-06T01:49:55Z")
Closed on May 6, 2021, 1:49am UTC