Fading all the LEDs on the D&T lamp boards

Explanation: On the D&T lamp boards, only pins 5, 6, 9, 10, and 11 (not 7, 8, or 12) are “PWM enabled” and work with the analogWrite function. Built into the hardware on those pins is a way to toggle very quickly between on and off, leading to a dimmer or brighter LED, depending on the ratio of “on” times to “off” times.

However, it’s possible to replicate this effect in software, which is what the SoftPWM Arduino library does.