In the simple IoT applications, from DIY Projects to the complex networks the sensors played a significant role always and here we will discuss how to make sensors using LM393 so let’s get started.

Introduction to LM393

The LM393 Is a type of comparator IC which is used for making sensors.

This IC compares two voltages and currents and gives a digital output of the quantity which is larger.  This chip consists of two independent precision voltage comparators with an offset voltage specification as low as 2.0 mV maximum for two comparators which were designed specifically to operate from a single power supply over a wide range of voltages.

Pin Configuration diagram of the LM393 

The Pin configuration diagram of the LM393 is given below.

By applying the analog signal to the comparator +input called the non-inverting input and the -ve input called inverting input , the comparator circuit will compare this two analog signals, if the analog on the non-inverting input is greater than the analog input on inverting then the output will swing to the logical high.

Now we will test the comparator in the LDR module 


From the above picture, it is clearly visible that the every sensor provides a 10K variable resistor for the adjustment of the voltage levels for precision arrangement .

  • Now we will adjust the voltage level in the non-invertig input side.

The complete circuit arrangement for the testing of the sensors 

The below picture shows the complete arrangement of the circuit for the testing of the sensors.

Make the circuit with the help of the above circuit diagram and follow the below steps.

  • Varying the 10K POT will vary the voltage levels in the non-inverting input side.
  • So by performing the above action we can actually vary the sensitivity of the LDR

Below are the two pictures in the different state of the sensor and it is completely in the sensing phase.

The above picture shows that the sensor module senses the dark

The above picture shows that the sensor module senses the light  

To make different sensors we have to just replace the LDR with the other sensors like flame , MQ05 , gas sensor and vibration sensor also and many others also.     

Introduction to IRS20957S

The IRS20957S is a special type of protected digital Audio Driver and the below picture is a class D audio amplifier 


Advantages of using this audio amplifier 

  • Efficiency of supply power requirements : The heat produced is very minimal by applying the switching model it can reduce the power loss in the final amplifier and allow for the efficiency of 90% to 95%.

Features of the IRS20957S

The features of the IRS20957S is listed below

  • Floating PWM input enables the easy half-bridge implementation 
  • It is a Programmable bidirectional over- current protection
  • Programmable preset dead times for improved THD performances 
  • High noise immunity is another advantage of this IRS20957S.
  • The device can be operated up to 800kHz.


So we have discussed the various sensors that can be used in various circuit applications so for buying them at Best price please visit at