PIR Sensor for Driveway Alert System

Project Overview

This project creates a driveway alert system that detects vehicles or people approaching your property and sends a notification to a receiver inside your home. It’s perfect for long driveways, rural properties, or anywhere you want to know when someone arrives.

Difficulty: Intermediate
Estimated time: 2-3 hours
Estimated cost: $40-60

How It Works

A weatherproof PIR sensor is placed at the driveway entrance. When a vehicle or person passes by, it sends a wireless signal to a receiver unit inside the house. The receiver can play a chime, flash an LED, or send a notification to your phone. For long driveways (up to 100m), LoRa or ESP-NOW is used; for shorter distances, 433MHz RF modules work well.

Materials Needed

ESP32 or Arduino (2) – one for transmitter, one for receiver
HC-SR501 PIR sensor (1) – outdoor version or weatherproof enclosure
LoRa modules (RAK811, Heltec) or NRF24L01 for wireless communication
Buzzer or speaker (for audible alert)
LEDs (for visual alert)
Battery pack (for remote transmitter)
Solar panel and charger (optional, for long-term deployment)
Weatherproof enclosure (for transmitter)
Jumper wires

System Architecture

[Driveway Sensor] ---Wireless (LoRa/NRF24L01)---> [House Receiver]
     |                                                    |
  PIR Sensor                                         Buzzer/LED
  Battery/Solar                                          Display

Circuit Diagram

Transmitter Unit

表

Transmitter Code (ESP32 with LoRa)

// Driveway Alert Transmitter
#include <SPI.h>
#include <LoRa.h>

const int pirPin = 2;
const int csPin = 5;
const int rstPin = 14;
const int dio0Pin = 2;

unsigned long lastSendTime = 0;
const unsigned long sendCooldown = 30000; // 30 seconds between alerts

void setup() {
  Serial.begin(115200);
  pinMode(pirPin, INPUT);
  
  LoRa.setPins(csPin, rstPin, dio0Pin);
  if (!LoRa.begin(915E6)) { // Use 868E6 for Europe, 915E6 for US
    Serial.println("LoRa init failed");
    while (1);
  }
  
  Serial.println("Driveway Transmitter Ready");
  delay(60000); // PIR warm-up
}

void sendAlert() {
  LoRa.beginPacket();
  LoRa.print("MOTION");
  LoRa.print(",");
  LoRa.print(millis());
  LoRa.endPacket();
  Serial.println("Alert sent");
}

void loop() {
  bool motion = digitalRead(pirPin) == HIGH;
  
  if (motion && (millis() - lastSendTime > sendCooldown)) {
    lastSendTime = millis();
    sendAlert();
    delay(2000); // Wait for transmission
  }
  
  delay(100);
}

Receiver Code (ESP32 with LoRa and Display)

// Driveway Alert Receiver
#include <SPI.h>
#include <LoRa.h>
#include <Wire.h>
#include <LiquidCrystal_I2C.h>

LiquidCrystal_I2C lcd(0x27, 16, 2);

const int csPin = 5;
const int rstPin = 14;
const int dio0Pin = 2;
const int buzzerPin = 4;
const int ledPin = 13;

int alertCount = 0;
unsigned long lastAlertTime = 0;
const unsigned long alertDuration = 5000; // 5 seconds

void setup() {
  Serial.begin(115200);
  pinMode(buzzerPin, OUTPUT);
  pinMode(ledPin, OUTPUT);
  digitalWrite(buzzerPin, LOW);
  digitalWrite(ledPin, LOW);
  
  lcd.init();
  lcd.backlight();
  lcd.setCursor(0, 0);
  lcd.print("Driveway Monitor");
  lcd.setCursor(0, 1);
  lcd.print("Ready");
  
  LoRa.setPins(csPin, rstPin, dio0Pin);
  if (!LoRa.begin(915E6)) {
    lcd.clear();
    lcd.print("LoRa init failed");
    while (1);
  }
  
  Serial.println("Receiver Ready");
}

void triggerAlert() {
  alertCount++;
  lastAlertTime = millis();
  
  digitalWrite(ledPin, HIGH);
  tone(buzzerPin, 2000, 500);
  
  lcd.clear();
  lcd.setCursor(0, 0);
  lcd.print("Vehicle detected!");
  lcd.setCursor(0, 1);
  lcd.print("Count: ");
  lcd.print(alertCount);
  
  Serial.printf("Alert #%d\n", alertCount);
}

void loop() {
  int packetSize = LoRa.parsePacket();
  if (packetSize) {
    String message = "";
    while (LoRa.available()) {
      message += (char)LoRa.read();
    }
    if (message.startsWith("MOTION")) {
      triggerAlert();
    }
  }
  
  if (millis() - lastAlertTime > alertDuration && digitalRead(ledPin) == HIGH) {
    digitalWrite(ledPin, LOW);
    lcd.clear();
    lcd.setCursor(0, 0);
    lcd.print("System Ready");
    lcd.setCursor(0, 1);
    lcd.print("Total alerts: ");
    lcd.print(alertCount);
  }
  
  delay(100);
}

Alternative: NRF24L01 Version (Shorter Range)

For shorter driveways (up to 100m), use NRF24L01 modules:

#include <SPI.h>
#include <nRF24L01.h>
#include <RF24.h>

RF24 radio(7, 8); // CE, CSN
const byte address[6] = "00001";

void setup() {
  radio.begin();
  radio.openWritingPipe(address);
  radio.setPALevel(RF24_PA_MAX);
  radio.stopListening();
}

void sendAlert() {
  const char text[] = "MOTION";
  radio.write(&text, sizeof(text));
}

Solar Power for Transmitter

For remote driveway sensors, add solar charging:

5V solar panel (5-10W)
TP4056 charging module
18650 lithium battery (2000-3000mAh)
Boost converter to 5V (if needed)

Installation Steps

Assemble transmitter: Place PIR sensor and ESP32 in weatherproof enclosure.
Position sensor: Mount at driveway entrance, 1.5-2m high, angled to detect vehicles.
Test range: Verify wireless communication between transmitter and receiver.
Assemble receiver: Place receiver unit inside house with buzzer/LED visible.
Power up: Connect batteries or solar panel to transmitter.
Final test: Drive vehicle up driveway, verify alert.

Project Extensions

Vehicle vs. person detection: Use dual sensors to distinguish between vehicles and pedestrians.
Direction detection: Add second sensor to detect arrival vs. departure.
Camera integration: Add ESP32-CAM to capture images when motion detected.
SMS alerts: Add GSM module to send text messages.
Gate control: Add relay to automatically open gate when vehicle approaches.

Troubleshooting

No signal: Check antenna connection. Reduce distance. Try different channel.
False alerts: Adjust PIR sensitivity. Avoid facing road traffic. Add cooldown timer.
Battery drains quickly: Use deep sleep mode. Reduce transmit frequency.
Receiver not responding: Check power supply. Verify LoRa initialization.

Conclusion

This driveway alert system provides early warning of visitors, packages, or intruders. With wireless communication, it’s easy to install even on long driveways.