This module is made of three functional elements, the sensor on the front of the module which performs the measurement, then the analog signal is sent to the amplifier.
This amplifies the signal according to the gain determined by the potentiometer and sends the signal to the analog output of the module.
The third part consists of a comparator that switches the digital output and the diode when the signal falls below a certain value.
This operation is ideal for temperature monitoring (KY-028), proximity detectors (KY-024, KY 025, KY-036), alarm monitoring (KY-037, KY-038) or flame detector (KY-026).
Sensor –> Arduino
D0 ( Digital output ) –> Digital 3
+ –> 5V
G ( ground ) –> GND
AO ( Analog output ) –> Analog 0