LDR Module

This Module is based on an onboard LDR sensor IC used to detect the presence of light or to measure the intensity of light. In the presence of light, the output switches to high. Whereas it becomes low in the absence of light. The sensitivity of the output signal can be adjusted using a potentiometer. This module comes with an M3 mounting hole for ease of attaching it to an object. The onboard LDR provides high sensitivity and is commonly used for light detection. LDR module also provides a power LED and a status LED as an indicator for the output and power.

LDR module provides both digital and analogue outputs. It exhibits high resistance when there is no incident light, therefore analogue output will be in a low state. When LDR is exposed to light the voltage level starts increasing based on the intensity of the incident light. When the intensity of the light is at the maximum level the voltage output will reach a maximum. So by using the onboard potentiometer we can adjust the intensity of light. Here the output voltage is proportional to the incident light on it. Analogue output module AO and AD modules can be connected through the AD converter, to get a more accurate light intensity value.

In the digital output, when the light is detected, the indicator LED D0 turns ON and the digital pin will go from logic high to logic low 0V state. LM393 Op-Amp Comparator IC was used to compare the actual value with the threshold value set using the potentiometer. Digital output D0 is directly connected to the MCU to detect high or low TTL, therefore detecting ambient light intensity changes.

Applications

• Automatic Street Light
• Detect Day or Night
• Position sensor
• Used along with LED as an obstacle detector
• Automatic Rearview mirror/bedroom lights