This is a prototype for a 8 * 8 pixel RGB LED display. Multiplexing and PWM-ing should be done by the host controller.
I have it working with 8 intensities per primary color on an Arduino.
LED intensity depends on the current though the LED (the forward current I)
The problem with LED matrices is that the cheaper ones (around 9 EUR) mix LED’s from different batches with different currents (I{{sub|f}}) and intensities at the same voltage. The more expensive models (around 25 USD) use LED’s from the same batch or bin.
Here is an example of one the less expensive LED matrix :
The way around this is to use constant current drivers like the TLC5916.
<more to follow>