To control the backlight of the display, we use the awesome LT3754 LED driver from Linear Tech
. The great thing about this driver is it is a cross between an efficient boost convert and a fully-matched constant-current LED driver. The boost converter half can take 9-12VDC and boost it up to ~22VDC and the LED driver half makes sure that each LED strand is driven with exactly 18.5mA for perfectly distributed light (which gives better color representation).
To control the backlight, we use a very tiny microcontroller (the ATtiny85 from AVR) which listens for button presses and then sends a 4KHz PWM signal to the LT3754 to tell it how much to dim the display.
How to control the backlight
The backlight is super easy to control. Press the UP
buttons until you reach the brightness level you like. If you want to turn off the backlight, press the Backlight On/Off
button. The backlight On/Off is different than the switch. If you turn off just the backlight, the computer will still recognize a monitor is there, you just wont be able to see the graphics since there's no backlight. If you turn off the switch the entire monitor is off, and it wont be recognized by the computer!
When the backlight or monitor is turned off and an on, it will revert to the same brightness you had before.