This is a simple arduino project for a soil moisture sensor that will light up a LED at a certain moisture level ... the resistance value and then pour water and measure it again. Use a mid value for ...

which measures the intensity of light bouncing back from an object as an Arduino drives the LED through all possible colors with PWM signals. The sensor needs to be white balanced before use but ...

We use them ... hook the LED up to a microcontroller. Setting it up in a “reverse biased” mode allows it to act as a sensor when attached to an IO pin, instead of acting as a light emitter.

I recently had to build an infrared close proximity sensor that could tell if something was dropped in a parcel delivery drop box. After some searching, I ended up ... light and by detecting its ...