The following procedures will show you how to build a touchless auto dispenser for hand sanitiser with simple IoT components and 3D printing.
Schematic (Procedures and source code)
|
|
| Component | Function |
| Development Board - Arduino UNO |
A Processor Unit in this project. The Arduino Uno will process the data collected from an Ultrasonic sensor, and control the servo motor to press the pump bottle of hand sanitiser. |
|
Ultrasonic Senor |
A key component to detect the distance between people and hands with the automatic dispenser. |
| Servo Motor | Driver to press the pump bottle. |
| 3D Printed Case | Mount the built IoT suite to a pump bottle. |
| Jumper Wire | Connect the Arduino Uno with IoT sensors and drivers. |
| USB Type B Cable | Connect power supply to the Ardiuno Uno. |
Student
| Cheung Lok Fai, Gary |
Department of Electrical Engineering |
(June 2020)
Part 1 - Procedure
1) Wiring up Arduino Uno, ultrasonic sensor and servo motor with jumper wire as shown in below.
2) Print the case, base plate and upper arm for IoT suite with 3D Printer.
| Download 3D Models | |
| Case | Part 1 and Part 2 |
| Base plate | Part 3 |
| Upper arm | Part 4 |
3) Assemble the ultrasonic sensor with the 3D printed base plate(Part 3). It can be done by hot glue or cable tie.
4) Assemble the ultrasonic sensor base plate(Part 3)to the upper arm(Part 4)with screw.
5) Assemble the servo motor and Arduino to the 3D printed case (Part 1 & 2). Mount the IoT Suite to the bump bottle.
In this model, we choose a bump bottle with 31mm diameter. The ring diameter can be adjusted in 3D model according to different brands of sanitizer.
Part 2 - Source Code for Arduino IDE
#include <Servo.h>
//defines servo objectServo myservo;
// defines pins numbers
const int trigPin = 5;
const int echoPin = 6;
// defines variable
int threshold = 20;
//define threshold for the sensing distance
int distance ;
void setup() {
pinMode(trigPin, OUTPUT); // Sets the trigPin as an Output
pinMode(echoPin, INPUT); // Sets the echoPin as an Input
Serial.begin(9600); // Starts the serial communication
myservo.attach(9, 500, 2400); // Refine the pulse width for MG996R
myservo.write(90); // Center to 90 degree first
delay(3000);
}
void loop() {
long duration;
distance = 0; // Clears the trigPin
digitalWrite(trigPin, LOW);
delayMicroseconds(2);
// Sets the trigPin on HIGH state for 10 micro seconds
digitalWrite(trigPin, HIGH);
delayMicroseconds(10);
digitalWrite(trigPin, LOW);
duration = pulseIn(echoPin, HIGH); // Reads the echoPin, returns the sound wave travel time in microseconds
distance = duration * 0.034 / 2; // Calculating the distance
if (distance < threshold) pulling_servo(); //Press the sanitizer if their are object within the threshold distance
else release_servo(); //Release servo if the distance back to normal
}
void pulling_servo() {
Serial.println(distance);
// Prints the distance on the Serial Monitor when it is lower than the threshold
myservo.write(0);
delay(2000);
}
void release_servo() {
Serial.println(distance);
// Prints the distance on the Serial Monitor when it is lower than the threshold
myservo.write(90);
delay(1000);
}
Part 3 - Reference
Medium - D.I.Y. Automatic Alcohol Dispenser: https://medium.com/asbavensky/d-i-y-automatic-alcohol-dispenser-a82bc3828de6
Ardruino Project Hub - Automatic Soap Dispenser © GPL3+: https://create.arduino.cc/projecthub/FANUEL_CONRAD/automatic-soap-dispenser-75abd6
Viral Science - Automatic Soap Dispenser: https://www.viralsciencecreativity.com/post/arduino-automatic-soap-dispenser