How to dim 16x32 RGB display

EL Wire/Tape/Panels, LEDs, pixels and strips, LCDs and TFTs, etc products from Adafruit

Moderators: adafruit_support_bill, adafruit

Please be positive and constructive with your questions and comments.
Locked
User avatar
scott216
 
Posts: 163
Joined: Sun Apr 12, 2009 11:08 am

How to dim 16x32 RGB display

Post by scott216 »

I'd like to dim the brightness of two 16x32 RGB LED displays using an analog output pin from an Arduino Mega. Initially, I was thinking of getting a voltage regulator chip where I could adjust the voltage, but that might not play nice with a PWM output from the Arduino. Now I'm thinking a transistor might be best, maybe a MOSFET. I'd appreciate any recommendations.

User avatar
adafruit_support_mike
 
Posts: 67446
Joined: Thu Feb 11, 2010 2:51 pm

Re: How to dim 16x32 RGB display

Post by adafruit_support_mike »

There's no practical way to control the brightness of an entire LED matrix with a single input. The amount of current used at any instant depends on the number of LEDs lit at that moment, and there's no guarantee that "50% power" would be distributed among all the LEDs equally.

To dim the LEDs, lower the PWM duty cycle for each one. You can create a single function to do that (our NeoPixel library's setBrightness() function applies a rather elegant gamma correction), but you need to handle the issue one LED at a time.

Locked
Please be positive and constructive with your questions and comments.

Return to “Glowy things (LCD, LED, TFT, EL) purchased at Adafruit”