Proximity Sensors: Capacitive and Inductive ( Comparison and Application )

Overview:

Let's talk about closure. I mean Proximity!
In this tutorial, we will be using two proximity sensors; inductive and capacitive. we will be making two basic application for both sensors and will be discussing its difference in terms of how they detect and work.

Hardware Used:

• Arduino Uno  

Software Used:

• Arduino IDE

Application Discussion:

A proximity sensor is a device that can detect the presence of nearby objects.
Today, proximity sensors are commonly used alongside Arduino for many applications, ranging from distance measurement to object detection.

The two mostly used proximity sensors are the Inductive proximity sensor and the Capacitive proximity sensor.

Inductive proximity sensor can only detect metal objects, specifically 
Ferrous metals such as iron and steel.

Inductive sensor can only detect metal because of the electromagnetic field. The inductive characteristics of the metal change the properties of the field when a metal target enters the electromagnetic field, and will alert the proximity sensor to the presence of a metallic target.

This type of proximity sensor is commonly used for metal detecting projects.

On the other hand, Capacitive proximity sensors, are not limited to metallic targets. Capacitive proximity sensors can detect anything that can carry an electrical charge such as glass and wood.

This type of proximity sensor can also detect liquids and is also used in liquid-level detection.

Capacitive sensor works kind of similarly with the inductive type, but when a ferrous or non-ferrous enters the sensitive zone (green lines), capacitance increases and will cause oscillation resulting to a detection of an object.

These are just two of many proximity sensors available at CreateLabz Store! Go visit Createlabz Store, where you can order hundreds of high quality electronic components and modules.

APPLICATION 1: Capacitive Proximity Sensor

Since Capacitive Proximity Sensors are good for liquid-level detection, then we will be making a water-level indicator with Water pump, 5v Relay, LEDs and Buzzer. 

Hardware Set-Up:

 *Note: 
             The BLUE WIRE on both Proximity Sensors is for GND
             The BLACK WIRE is for the INPUT PIN
             The RED WIRE is for the SUPPLY VOLTAGE. 

Software Set-Up:

This project doesn't need a library.
Open your Arduino IDE and Upload the code below or you can download it on GITHUB. 

Code:

#define Capacitive 2
#define LED1 5
#define LED2 6
#define Relay 8

void setup(){
pinMode(2,INPUT);
pinMode(5, OUTPUT);
pinMode(6, OUTPUT);
pinMode(8,OUTPUT);
}

void loop(){
 if (digitalRead(Capacitive) == HIGH)
 { digitalWrite(5, HIGH); 
   digitalWrite(6, LOW);
   digitalWrite(8,LOW);
 }

 else {
  digitalWrite(5,LOW);
  digitalWrite(6, HIGH);
  digitalWrite(8,HIGH);
 }
}

#define Inductive 3
#define Led1 5
#define Led2 6
#define buzzer 7
#define value

void setup()
{
Serial.begin(9600);
pinMode(Inductive,INPUT);
pinMode(Led1,OUTPUT);
pinMode(Led2,OUTPUT);
pinMode(buzzer,OUTPUT);

}
void loop(){
value = analogRead(Inductive);
if(value!=state)
{
  state=value;
  if (state==0){
  digitalWrite(5,HIGH);
  digitalWrite(6, LOW);
  analogWrite(7, HIGH);
  tone(7, 500);
  }
    
   else{
  digitalWrite(5,LOW);
  digitalWrite(6, HIGH);
  analogWrite(7, LOW);
  noTone(7);
    }
 }

Video Output of Inductive Proximity Sensor

Conclusion

This tutorial was able to differentiate between the two proximity sensors and even made its own application. The Capacitive Proximity sensor can basically detect anything, whether solid or liquid, and therefore a great sensor for the detection of water levels. While, the Inductive Proximity Sensor focuses on the detection of magnetic metals such as steel.

Both sensors are easy to use together with other modules. Just make sure to remember that the blue wire is the ground and not the black wire. 

Reference:

Proximity Sensors: Inductive and Capacitive Proximity Sensors with Arduino (electroniclinic.com)