Ambient Light Sensor

An ambient light sensor is a component which is utilize in mobile devices, smartphone, notebooks, LCD, TVs and automotive displays. Ambient light sensor work on the principle of photo detector which used for detecting the sum of ambient light nearby to it and approximately reduces the mobile and other devices screen’s light. Therefore to avoid the screen brightness whenever the users are modified for vision within the dark room otherwise less brightness when they utilized outdoor during the day light. It helps to make devices run long time and increase the lifetime of the battery.

There are three type of the Ambient Light Sensor namely

• Photodiode
• Photonic ICs
• Phototransistor

Ambient Light Sensor circuit

Ambient light circuit is considered as harvesting of the light energy source to control bathroom fixture, remote weather sensor, for heartbeat monitoring and low power devices. The ambient light can be measured accurately by using heat of energy. The design of harvesting system illustrate an easy and commercial circuit which offers a voltage than that a proportional to the strength of ambient light.

The sensor used in the circuit is an LDR i.e. Light depending resistor and the resistance of this change with ambient light energy strength. When the sensor is in the dark light then the resistance will be decreased from the millions of ohms in darkness as well as few hundreds of ohms in day light.

Thus it is capable of detecting small or large fluctuation within the light level, also it can differentiate among one of light bulbs, straight sunlight, entire darkness, etc. so the physical arrangement of the circuit is done according to the correct light scenario. Also the sensor which is used in this circuit arrangement is to be connected in a clear and waterproof field.

The ambient light sensor circuit give an output voltage that react to both the light intensity and the input voltage with the LDR which is working as the gain resistor to the instrumentation amplifier.

Application

• Ambient light sensor is used to control the backlight of an LCD display based application to control display brightness of mobile and other devices for reducing the battery life.
• These sensors are also used in all types of the light source like natural sunlight, incandescent lamps, and fluorescent.
• Ambient light sensor from the AMI semiconductors is used within both automotive as well as consumer applications.
• The main feature of these sensors is allowing the display controller to regulate the intensity in less dark current.
• The APDS-9004 ambient light sensor from Avago Technologies is used for black lighting control in DVD players, consumer LCD displays, mobile phones, notebook PCs, digital cameras, etc.
• The main feature of this sensor is an automatic alteration to save power and to increase the LCD screens life in handy display devices.
• This sensor is also used be used in indoor as well as outdoor lighting for turning ON/OFF which include street lighting, electronic signals as well as signs.