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Light Sensor Circuit

2014-11-28 12:06  
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Ambient Light Sensor Circuit

Light sensor circuit, such as the name is a circuit that utilizes the light intensity / beam for the other applications do automatically via the relay to switch on / off under certain conditions. Applications such as these and more we encounter in everyday life, such as automatic garden lights, LED lighting / IR LED, light activated alarm, and others.

A Light sensor requires a light detector which can be a Light Dependent Resistor (LDR) or Photodiode. The circuit measures the ambient light intensity is called ambient light sensor circuit. Basically, it can simply be alight sensor circuitconsists of three parts, namely the ambient light sensor, relay driver, and application design. So it can be concluded that a light sensor circuit is a light sensor switch circuit.

LDR & Photodiode Sensors

LDR & Photodiode Sensors

The Light Dependent Resistor (LDR)

Measurement of ambient light level of the light sensor can use the LDR. An LDR (light dependent resistor) is composed of semiconductor material plate with two electrodes on its surface. Resistor value of an LDR is determined or strongly influenced by light.

In the dark or dim light environments, disk material contains free electrons in a relatively very small amount. There are a number of free electrons to flow of electric charge. That is, the material is a poor conductor of electric current, because the very high resistance materials.

In an environment with sufficient light, more electrons can escape from the atoms of a semiconductor material. There are more free electrons that can drain the electric charge. Under these circumstances, the material is a good conductor. Low electrical resistance material. Brighter light on the material, electrons are more available, and the lower the electrical resistance of these materials.

The Photodiode

Photodiode light sensor construction is similar to a conventional diode PN-junction diode except that the outer casing is either transparent or have a clear lens to focus light to a PN junction for increased sensitivity. Intersection will respond to light, especially the longer wavelengths such as red and infrared light than visible light.

Light Sensor Circuit Diagram

Various applications relating to the ambient light sensor can be easily met on the internet, that you can follow the links associated with thelight sensor circuitdiagram according to the keyword or phrase you are looking for. However, here only to deliver the basic understanding of light sensor.

Simple Light Sensor Circuit

Simple Light Sensor Circuit

Here below are some examples of applications that measure the ambient light level using the LDR which is used to detect light in the environment. Then the output signal of the circuit is routed to a relay driver to switch the application after it. And is commonly referred to as a light sensor switch circuit.

Smart Garden LightInfrared IlluminatorAutomatic Light Controller

Presumably, there is little understanding of a light detector, especially on how to make a simple light sensor switch. There are many more variations on how to design alight sensor circuit.

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