Temperature measurement module KY-028 for Arduino

The sensor is used to control the air temperature in the room when building temperature controllers, automation of heating systems, automation of ventilation systems. The comparator detects the temperature exceeding the set threshold and issues a logic signal to the digital output D0 and at the same time allows you to evaluate the temperature value at the analog output A0.

Due to the output at which a signal is generated with a logical one or zero level, which indicates whether or not the temperature threshold has been exceeded, it is convenient to use the temperature sensor module in circuits based on discrete elements without using a microcontroller. For example, if the output of the KY-028 module is connected to the gate of a field-effect transistor of sufficient power to turn on a fan operating from 12 V. According to this scheme, an automatic cooling device for an electronic device can be assembled.

The receiving element of the sensor is a thermistor. It is connected to the input of the LM393 comparator chip. With the help of a tuning resistor, the comparator threshold is adjusted. When exceeding
the temperature of the set threshold at the output D0 will be a high voltage level. If the temperature is below the set threshold, then output D0 will go low.

Indicator L1 shows the presence of supply voltage. LED L2 turns on when the ambient temperature exceeds the set threshold. With it, it is convenient to configure the KY-028 module.

When switched on, output A0 has a voltage corresponding to the temperature in the room. This temperature is known only approximately. There are ways to accurately determine which temperature corresponds to which voltage of the output A0. Squeeze the thermistor with your fingers. We will find out the analog output voltage at 36.6°C. These data can be used in the future. Another calibration point is 0 °C. Use a secure plastic bag with melting ice or snow from the refrigerator. We get a new voltage value that can be
take as a starting point.

Technical parameters of the module:

Supply voltage, V 3.3 ... 5.5
Operating temperature, °C 0 ... 70
Module dimensions, mm 35 x 15 x 12.