LDR SENSOR MODULE


General Description:


The LDR sensor module is a low-cost sensor capable of measuring and detecting light intensity. Also known as a photoresistor sensor, it features an onboard LDR (Light Dependent Resistor) for light detection. The module typically has four terminals, with a digital output (DO) pin and an analog output (AO) pin. The digital output goes high in the absence of light and low in its presence. The sensor's sensitivity can be adjusted using an onboard potentiometer.


Working Principle:


It works on the principle of photoconductivity whenever the light falls on its photoconductive material, it absorbs its energy, and the electrons of that photoconductive material in the valence band get excited and go to the conduction band thus increasing the conductivity as per the increase in light intensity. Also, the energy in incident light should be greater than the band gap energy so that the electrons from the valence band get excited and go to the conduction band. The LDR has the highest resistance in the dark around 1012 Ohm and this resistance decreases with the increase in Light.


Specifications:


1. Operating Voltage: 3.6V to 5V DC

2. Adjustable potentiometer to adjust the sensitivity

3. LM393 comparator IC for digital output

4. Easy to install thanks to bolt hole provided

5. Digital Output

6. Using sensitive photosensitive resistance sensor

7. The comparator output signal is clean, has good waveform, driving ability, and more than 15mA.


Requirements


S. No. Component Name Values
1 IC: LM393 (Op-Amp)
2 LDR (Light Dependent Resistor)
3 Resistors 1K,10K
4 Potentiometer (VR) 10K
5 Capacitor 0.1uF
6 LED
7 Male Connectors 4

Pin configuration:


S. No. Pins Pin Description
1 VCC Positive power supply 3.3-5V
2 GND Connect to Ground
3 D0 TTL switching signal output
4 A0 Analog output

Pin Diagrams:





Applications:


1. Automatic Lighting Systems

2. Security Systems

3. Optical Circuit Design

4. Solar Street Lamps


For more info: Refer the Datasheets!


DATASHEET_LDR
LM393_DATASHEET