Here I made such a simple, and most importantly, very necessary backlight, with my own hands from a Chinese lamp. After all, you can’t buy eyes, and working on a computer in a dimly lit room is very harmful to the eyes.
This lamp can be bought for 100-200 rubles. It is powered by 3 finger batteries, that is - 4.5 volts.
I naturally took it apart. In it, the entire circle of LEDs was divided into four boards.
I screwed these boards with small screws to the monitor. Two on each side.
I connected both sides in parallel and powered it all from the USB port through a 10 Ohm resistor using a USB cable from an old printer. The resistor can adjust the brightness by changing its resistance in the range from 100 to 1 ohm.
It turned out very conveniently: I turn on the computer - the backlight turns on, turn off the computer - the backlight turns off.
Although the shooting was during the day, believe me: at night it is even better.