RF Transmitter and Receiver for Wireless Alarm System

Projects Networking, Protocols, and Devices
1

Hello, I have a problem with my project. The RF transmitter I am using is sending but the receiver is not receiving any signal.

Transmitter Code:

#include <Wire.h>
#include <LiquidCrystal_I2C.h>
#include <DS3231.h>
#include <RH_ASK.h>   // Include RadioHead library for RF module
#include <SPI.h>

// Set the LCD address to 0x3F for a 16 chars and 2 line display
LiquidCrystal_I2C lcd(0x27, 16, 2);

DS3231 rtc; // Initialize DS3231 instance

// Pin configurations
int pset = 8;   // Pushbutton for setting alarm
int phour = 9;  // Pushbutton for hour
int pmin = 10;  // Pushbutton for minutes
int pexit = 11; // Pushbutton for exit of set alarm
int h = 0; // Initialize alarm hour
int m = 0; // Initialize alarm minute
int activate = 0; // Alarm mode status
bool debounceDelay = 200; // Debounce delay in milliseconds

// RF transmitter setup
#define RF_PIN 12 // Change to the pin you're using for the RF module
RH_ASK rf_driver(2000, RF_PIN, -1, -1); // Baudrate is set to 2000, adjust as necessary

void setup() {
  pinMode(pset, INPUT_PULLUP);
  pinMode(phour, INPUT_PULLUP);
  pinMode(pmin, INPUT_PULLUP);
  pinMode(pexit, INPUT_PULLUP);

  // Initialize Serial for debugging
  Serial.begin(9600);

  // Initialize LCD
  lcd.begin();
  lcd.backlight();

  // Set the RTC date and time if necessary
  rtc.setClockMode(false); // Use 24-hour mode
  if (rtc.getYear() == 0) {
    rtc.setYear(25);      // Year (last two digits)
    rtc.setMonth(1);      // Month
    rtc.setDate(24);      // Day
    rtc.setHour(9);       // Hour
    rtc.setMinute(24);    // Minute
    rtc.setSecond(0);    // Second
  }

  // Initialize RF transmitter
  if (!rf_driver.init()) {
    Serial.println("RF transmitter initialization failed!");
    while (1);
  }
}

void loop() {
  bool h12, PM_time, Century;
  int Hour = rtc.getHour(h12, PM_time); // Retrieve hour
  int Min = rtc.getMinute();           // Retrieve minute

  // Display time and date when not in alarm-setting mode
  if (activate == 0) {
    lcd.setCursor(0, 0);
    lcd.print("Time: ");
    lcd.setCursor(6, 0);
    if (Hour < 10) lcd.print('0'); // Add leading zero
    lcd.print(Hour);
    lcd.print(":");
    if (Min < 10) lcd.print('0'); // Add leading zero
    lcd.print(Min);

    lcd.setCursor(0, 1);
    lcd.print("Date: ");
    lcd.setCursor(6, 1);
    lcd.print(2000 + rtc.getYear()); // Add 2000 to get the full year
    lcd.print("-");
    if (rtc.getMonth(Century) < 10) lcd.print('0'); // Add leading zero
    lcd.print(rtc.getMonth(Century));
    lcd.print("-");
    if (rtc.getDate() < 10) lcd.print('0'); // Add leading zero
    lcd.print(rtc.getDate());

    // Check for alarm setting button press
    if (digitalRead(pset) == LOW) {
      delay(debounceDelay); // Debounce
      if (digitalRead(pset) == LOW) { // Confirm button is still pressed
        activate = 1; // Enter alarm setting mode
        lcd.clear();
        delay(200);
      }
    }
  }

  // Alarm setting mode
  while (activate == 1) {
    lcd.setCursor(0, 0);
    lcd.print("Set Alarm");
    lcd.setCursor(0, 1);
    lcd.print("Hour= ");
    lcd.setCursor(9, 1);
    lcd.print("Min= ");

    // Check for hour button press
    if (digitalRead(phour) == LOW) {
      delay(debounceDelay); // Debounce
      if (digitalRead(phour) == LOW) { // Confirm button is still pressed
        h++;
        if (h > 23) h = 0; // Reset after 23
        lcd.setCursor(5, 1);
        lcd.print(h < 10 ? "0" : ""); // Add leading zero
        lcd.print(h);
        delay(200);
      }
    }

    // Check for minute button press
    if (digitalRead(pmin) == LOW) {
      delay(debounceDelay); // Debounce
      if (digitalRead(pmin) == LOW) { // Confirm button is still pressed
        m++;
        if (m > 59) m = 0; // Reset after 59
        lcd.setCursor(13, 1);
        lcd.print(m < 10 ? "0" : ""); // Add leading zero
        lcd.print(m);
        delay(200);
      }
    }

    // Check for exit button press
    if (digitalRead(pexit) == LOW) {
      delay(debounceDelay); // Debounce
      if (digitalRead(pexit) == LOW) { // Confirm button is still pressed
        activate = 0; // Exit alarm setting mode
        lcd.clear();
        delay(200);
      }
    }

    // Continuously update hour and minute display
    lcd.setCursor(5, 1);
    lcd.print(h < 10 ? "0" : ""); // Add leading zero
    lcd.print(h);
    lcd.setCursor(13, 1);
    lcd.print(m < 10 ? "0" : ""); // Add leading zero
    lcd.print(m);
  }

  // Check if it's time to trigger the alarm
  if (Hour == h && Min == m) {
    const char *msg = "Alarm Triggered";
    rf_driver.send((uint8_t *)msg, strlen(msg));
    rf_driver.waitPacketSent();
    Serial.println("RF Signal Sent: Alarm Triggered");
  }

Receiver Test Code:

#include <RH_ASK.h>
#include <SPI.h>  // Not actually used but needed to compile

RH_ASK rf_driver;

void setup() {
  rf_driver.init();          // Initialize the RF driver
  Serial.begin(9600);        // Start the serial communication
}

void loop() {
  uint8_t buf[RH_ASK_MAX_MESSAGE_LEN]; // Buffer to store received messages
  uint8_t buflen = sizeof(buf);

  if (rf_driver.recv(buf, &buflen)) {  // Check if data is received
    buf[buflen] = '\0';  // Null-terminate the received message
    Serial.print("Received: ");
    Serial.println((char*)buf);  // Print the received message
  }
}
2

what transmitters/receivers are you using? give a link?
what host microcontroller are you using?
how you connected and powered the devices?
what is the distance between the transmitter and receiver? what is the environment, e.g walls, trees, etc?

3

How do you know ?

4

You need to post wiring diagrams.