12. Intput devices¶
WEEK 12¶
This week’s assignments are:
- To measure something using an input sensor to a microcontroller board that I designed and read it
- To probe an input device’s analog levels and digital signals(Group Assignment added HERE)
Ultrasonic Sensor¶
Using the board I made the previous week I wanted to connect an ultrasonic sensor to get the reading in centimeters in the serial monitor. I also thought of writing a code for the light to blink when the ultrasonic sensor detects an object and also to blink faster when the object moves closer.
So I started by using an Ultrasonic Sensor HC-SR04 and connected the pins to an Arduino Mega 2560 board to run a sample code…
// ---------------------------------------------------------------- //
// Arduino Ultrasoninc Sensor HC-SR04
// Re-writed by Arbi Abdul Jabbaar
// Using Arduino IDE 1.8.7
// Using HC-SR04 Module
// Tested on 17 September 2019
// ---------------------------------------------------------------- //
#define echoPin 2 // attach pin D2 Arduino to pin Echo of HC-SR04
#define trigPin 3 //attach pin D3 Arduino to pin Trig of HC-SR04
// defines variables
long duration; // variable for the duration of sound wave travel
int distance; // variable for the distance measurement
void setup() {
pinMode(trigPin, OUTPUT); // Sets the trigPin as an OUTPUT
pinMode(echoPin, INPUT); // Sets the echoPin as an INPUT
Serial.begin(9600); // // Serial Communication is starting with 9600 of baudrate speed
Serial.println("Ultrasonic Sensor HC-SR04 Test"); // print some text in Serial Monitor
Serial.println("with Arduino UNO R3");
}
void loop() {
// Clears the trigPin condition
digitalWrite(trigPin, LOW);
delayMicroseconds(2);
// Sets the trigPin HIGH (ACTIVE) for 10 microseconds
digitalWrite(trigPin, HIGH);
delayMicroseconds(10);
digitalWrite(trigPin, LOW);
// Reads the echoPin, returns the sound wave travel time in microseconds
duration = pulseIn(echoPin, HIGH);
// Calculating the distance
distance = duration * 0.034 / 2; // Speed of sound wave divided by 2 (go and back)
// Displays the distance on the Serial Monitor
Serial.print("Distance: ");
Serial.print(distance);
Serial.println(" cm");
}
Also got the readings in the serial monitor in Arduino IDE…
Since the Arduino Mega board was a success I tried with the programmer I made in the previous weeks using the same program but by changing the pins…
Then I added a code to make the LED blink depending on how close the object is placed near the ultrasonic sensor
if(distance<5){
digitalWrite(8,HIGH);
delay(50);
digitalWrite(8,LOW);
delay(50);
}
else if(distance<10){
digitalWrite(8,HIGH);
delay(100);
digitalWrite(8,LOW);
delay(100);
}
else if(distance<15){
digitalWrite(8,HIGH);
delay(200);
digitalWrite(8,LOW);
delay(200);
}
else if(distance<20){
digitalWrite(8,HIGH);
delay(400);
digitalWrite(8,LOW);
delay(400);
}
else{
digitalWrite(8,LOW);
}
Then later added a speaker to have a buzzer output…
if(distance<5){
digitalWrite(8,HIGH);
tone(buzzer, 1000); // Send 1KHz sound signal...
delay(50);
digitalWrite(8,LOW);
noTone(buzzer); // Stop sound...
delay(50);
}
else if(distance<10){
digitalWrite(8,HIGH);
tone(buzzer, 1000); // Send 1KHz sound signal...
delay(100);
digitalWrite(8,LOW);
noTone(buzzer); // Stop sound...
delay(100);
}
else if(distance<15){
digitalWrite(8,HIGH);
tone(buzzer, 1000); // Send 1KHz sound signal...
delay(200);
digitalWrite(8,LOW);
noTone(buzzer); // Stop sound...
delay(200);
}
else if(distance<20){
digitalWrite(8,HIGH);
tone(buzzer, 1000); // Send 1KHz sound signal...
delay(400);
digitalWrite(8,LOW);
noTone(buzzer); // Stop sound...
delay(400);
}
else{
digitalWrite(8,LOW);
}