16x24 Arrays of RGB LEDs

The RGB LEDs contain full color pixels arranged in 16 wide by 24 tall arrays which can be used to display informational graphics, audio visualizations, and tunable ambient lighting.

The TLC5940 LED PWM driver is the most significant part used in this project which uses a clocked serial data input and provides 12 bits of PWM resolution on each of 16 outputs. Since there are three elements per RGB LED, it would add up very quickly because the TLC5940 would normally require one output for each LED element. Common cathode LEDs are used since the TLC5940 is a sink-type driver. The cathode is controlled by the TLC5940 while the power is strobed into the RGB anodes.

Several rows of LEDs are strobed by the TLC5940 and the shift data input can be operated quickly enough to run a few PWM cycles before having to switch to a new row. A flicker appearance is provided at 600Hz or above due to the persistence vision of the eyes since each LED is being activated 100 times per second.

The Atmel ATmega microcontroller controls the functions such as storing pixel data and generating a grayscale clock.

Rest of the project