Light Intensity Meter Using Ldr

Working of ldr controlled led using arduino.

Light intensity meter using ldr.

In order to detect the intensity of light or darkness we use a sensor called an ldr light dependent resistor. It s made up of such material whose conductivity varies as per light falls on it. The circuit utilizes an analog meter of 0 to 10 volts. We previously made many circuits using ldr which use ldr to automate the lights according to requirement.

Ldr are used most of times to detect presence of light or for measuring the intensity of light. It works on the principle of photoconductivity. At the end of this instructable you will be able to build a working circuit and program an ldr light sensor to be able to read sunlight and print it on your com. Light intensity meter using at89c52 microcontroller.

The ldr is a special type of resistor that allows higher voltages to pass through it low resistance whenever there is a high intensity of light and passes a low voltage high resistance whenever it is dark. Typically an ldr will have 1mω 2mω at total darkness 10 20kω at 10 lux 2 5kω at 100 lux. The light sensor for a lux meter can be one of several different types of sensors including photodiodes and phototransistors but the easiest to use and often the most readily available type of sensor is a photoresistor or light dependent resistor ldr. The voltage divider output is feed to the analog pin of the arduino.

Measuring light using light sensor. The circuit is very simple and convenient using only a few ldr variable resistor transistor and meter components. So the led does not light. There are different types of ldr as shown in above figure and each have different specifications.

This is an instructable on our class project about measuring light using a light sensor. This basic light intensity meter circuit can be used in a wide range of electronic projects and experiments to calculate the light intensities.