Don't just learn technology. Build it.

1// Sample: Smart Dustbin
2// Board: Arduino UNO | Generated by the STEMA Code Lab
3
4#include <Servo.h>
5
6const int TRIG_PIN = 9;
7const int ECHO_PIN = 10;
8Servo servo;
9
10long readDistanceCm() {
11  digitalWrite(TRIG_PIN, LOW);
12  delayMicroseconds(2);
13  digitalWrite(TRIG_PIN, HIGH);
14  delayMicroseconds(10);
15  digitalWrite(TRIG_PIN, LOW);
16  long duration = pulseIn(ECHO_PIN, HIGH, 30000);
17  return duration * 0.0343 / 2; // speed of sound, there and back
18}
19
20void setup() {
21  Serial.begin(9600);
22  pinMode(TRIG_PIN, OUTPUT);
23  pinMode(ECHO_PIN, INPUT);
24  servo.attach(6);
25  servo.write(0);
26}
27
28void loop() {
29  // 1. Sense
30  long distance = readDistanceCm();
31  Serial.print("Distance (cm): "); Serial.println(distance);
32
33  // 2. Decide
34  bool activate = (distance > 0 && distance < 20);
35
36  // 3. Act
37  if (activate) {
38    servo.write(90);
39  } else {
40    servo.write(0);
41  }
42
43  delay(200);
44}