Traffic Light (IOT)

SN	COMPONENT INTRODUCTION	QUANTITY	PURCHASE LINK
1	Arduino UNO R4 Wifi	1	BUY
2	USB Type-C cable	1	×
3	Breadboard	1	BUY
4	Wires	Several	BUY
5	Traffic Light LED	1	BUY

Follow the steps below to configure the dashboard.
1.Create New Dashboard

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2.Add Widgets

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3.Link Variable

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4.Remember to click Done

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After completing the above configuration, return to the Things page and open the sketch.

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When you have completed the configuration of the Things and Dashboard, as well as the connection and network setup of the Arduino WiFi board, the thingProperties.h and Sketch Secrets files will be generated automatically. If Sketch Secrets is not generated, please manually enter the connected SSID and OPTIONAL_PASS

Copy this code into Arduino Cloud.

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Don’t forget to select the board(Arduino UNO R4 WIFI) and the correct port before clicking the Upload button.

#include "thingProperties.h"

// ========== Hardware configuration ==========
const uint8_t PIN_RED    = 3;
const uint8_t PIN_YELLOW = 5;
const uint8_t PIN_GREEN  = 6;

// Common cathode (to GND) → true; Common anode (to 5V) → false
const bool ACTIVE_HIGH = true;
// ============================================

enum LightState : int { RED = 0, YELLOW = 1, GREEN = 2, ALL_OFF = 3 };

inline void writeLamp(uint8_t pin, bool on) {
  if (ACTIVE_HIGH) digitalWrite(pin, on ? HIGH : LOW);
  else             digitalWrite(pin, on ? LOW  : HIGH);
}

void setLights(LightState s) {
  writeLamp(PIN_RED,    s == RED);
  writeLamp(PIN_YELLOW, s == YELLOW);
  writeLamp(PIN_GREEN,  s == GREEN);
  currentState = static_cast<int>(s);  // Report back to cloud
}

void setup() {
  Serial.begin(115200);
  pinMode(PIN_RED, OUTPUT);
  pinMode(PIN_YELLOW, OUTPUT);
  pinMode(PIN_GREEN, OUTPUT);

  // Turn all off at startup
  setLights(ALL_OFF);

  // Connect to IoT Cloud
  initProperties();
  ArduinoCloud.begin(ArduinoIoTPreferredConnection);
  setDebugMessageLevel(2);
  ArduinoCloud.printDebugInfo();
}

void loop() {
  ArduinoCloud.update();
}

// ========== Cloud button callbacks ==========
void onCmdRedChange() {
  if (cmdRed) {
    setLights(RED);
    // Reset all three buttons to avoid keeping them “on” in the dashboard
    cmdRed = false; cmdYellow = false; cmdGreen = false;
  }
}

void onCmdYellowChange() {
  if (cmdYellow) {
    setLights(YELLOW);
    cmdRed = false; cmdYellow = false; cmdGreen = false;
  }
}

void onCmdGreenChange() {
  if (cmdGreen) {
    setLights(GREEN);
    cmdRed = false; cmdYellow = false; cmdGreen = false;
  }
}

/*
  Since Angle3 is READ_WRITE variable, onAngle3Change() is
  executed every time a new value is received from IoT Cloud.
*/
void onAngle3Change()  {
  // Add your code here to act upon Angle3 change
}
/*
  Since CurrentState is READ_WRITE variable, onCurrentStateChange() is
  executed every time a new value is received from IoT Cloud.
*/
void onCurrentStateChange()  {
  // Add your code here to act upon CurrentState change
}

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Arduino Project

Arduino IoT Cloud Traffic Light Project

Course Introduction

Required Components

Wiring

Common Connections: