Browse over 10,000 Electronics Projects

Light detector

Light detector

It is a light detector with no microprocessors, just simple electronics.It has only two circuits, one turns an LED off when theres no light, and the other turns an LED on when theres no light.
Now an explaination what some parts do.

on the first circuit the 1.2K resistor controls the sensitivity, go ahead change it! if it’s 10K you will need total darkness to turn the LED off, so change it betwen 1K and 10K less than 1K will be way sensitive and wont work, and over 10K you will need something darker than total darkness, wich i dont think exists, maybe outer space 😛


the second circuit the 10K resistor also controls the sensitivity, if you put 150K you will need total darkness to turn the LED on, so go ahed change it aswell! but only betwen 1K and 150K.

If it doesnt work: check the polarities of the LED, and see if the transistor is the right way in, if the LED doesnt go on, on the first circuit, dont be sad, that circuit is tuned so it works in my room, just grab a potenciometer and tune it the way you want to, then with a multimeter read the resistance of the pot, and put the closest resistor you can find to that resuslt, thats how i got 1.2K and 10K.

Visit Here for more.