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Automatic soap dispenser

The Automatic Soap Dispenser project uses an Arduino Uno board along with an infrared obstacle avoidance sensor and a water pump. The sensor detects the presence of an object such as a hand, which activates the water pump to dispense soap.

1. Build the Circuit

• Arduino UNO R4 Minima Board

• IR Obstacle Avoidance Sensor Module

• Centrifugal Pump

2. Code

1. Open the 04-Automatic_soap_dispenser.ino file under the path of ultimate-sensor-kit\fun_project\04-Automatic_soap_dispenser, or copy this code into Arduino IDE.

3. Code explanation

The main idea behind this project is to create a hands-free soap dispensing system. The infrared obstacle avoidance sensor detects when an object (like a hand) is close. Upon detecting an object, the sensor sends a signal to the Arduino, which in turn triggers the water pump to dispense soap. The pump stays active for a brief period, dispensing soap, then turns off.

1. Defining the pins for the sensor and the pump

   In this code snippet, we define the Arduino pins that connect to the sensor and pump. We define pin 7 as the sensor pin and we will use the variable sensorValue to store the data read from this sensor. For the water pump, we use two pins, 9 and 10.

   const int sensorPin = 7;
   int sensorValue;
   const int pump1A = 9;
   const int pump1B = 10;
   

2. Setting up the sensor and pump

   In the setup() function, we define the modes for the pins we’re using. The sensor pin is set to INPUT as it will be used to receive data from the sensor. The pump pins are set to OUTPUT as they will send commands to the pump. We ensure that the pin pump1B starts in a LOW state (off), and we start the serial communication with a baud rate of 9600.

   void setup() {
     pinMode(sensorPin, INPUT);
     pinMode(pump1A, OUTPUT);
     pinMode(pump1B, OUTPUT);
     digitalWrite(pump1B, LOW);
     Serial.begin(9600);
   }
   

3. Continuously checking the sensor and controlling the pump

   In the loop() function, the Arduino constantly reads the value from the sensor using digitalRead() and assigns it to sensorValue(). It then prints this value to the serial monitor for debugging purposes. If the sensor detects an object, sensorValue() will be 0. When this happens, pump1A is set to HIGH, activating the pump, and a delay of 700 milliseconds allows the pump to dispense soap. The pump is then deactivated by setting pump1A to LOW, and a 1-second delay gives the user time to move their hand away before the cycle repeats.

   void loop() {
     sensorValue = digitalRead(sensorPin);
     Serial.println(sensorValue);
     if (sensorValue == 0) {
       digitalWrite(pump1A, HIGH);
       delay(700);
       digitalWrite(pump1A, LOW);
       delay(1000);
     }
   }