Introduction: Wireless PIR Sensor Alarm
This is a simple wireless PIR sensor alarm.The device consists of two parts.One is a transmitter that contains PIR sensor and a transmitter module.A second receiver consisting receiving module and piezo speaker. Test your PIR sensor before you made this with any code from internet.
Step 1: Parts
You need:
1. Two arduinos any version
2. PIR sensor
3. Piezo speaker
4: RF 433MHz or 315 MHz module
5. 10Kohm resistor
Step 2: Transmitter
This is code of transmitter. When PIR sensor detects human movement transmitter sends uppercase letter A. When pir sensor it holds no signal transmitter sends lowercase letter a.
int pirPin = 2;
int statePir = 0;
#include <VirtualWire.h>
void setup(){
Serial.begin(9600);
vw_setup(2000);
vw_set_tx_pin(3);
pinMode(pirPin,INPUT);
}
void loop(){
statePir = digitalRead(pirPin);
if (statePir == HIGH){
const char *msg = "A";
vw_send((uint8_t *)msg, strlen(msg));
vw_wait_tx();
}
if (statePir == LOW){
const char *msg = "a";
vw_send((uint8_t *)msg, strlen(msg));
vw_wait_tx();
}
}
Step 3: Receiver
Here is the code for receiver. Piezo play very loud alarm sound.
int led = 13;
int speaker = 10;
#define wait 1
#define time 100
int freq = 0;
#include
void setup(){
Serial.begin(9600); // Debugging only
vw_setup(2000);
vw_set_rx_pin(11);
vw_rx_start();
pinMode(speaker, OUTPUT);
pinMode(led, OUTPUT);
}
void loop(){
uint8_t buf[VW_MAX_MESSAGE_LEN];
uint8_t buflen = VW_MAX_MESSAGE_LEN;
if (vw_get_message(buf, &buflen))
{
for (int i = 0; i < buflen; i++)
{
if(buf[i] == 'A') {
digitalWrite(led, HIGH);
digitalWrite(speaker, HIGH);
for (freq = 500; freq < 3000; freq += 10)
{
tone(speaker, freq, time);
delay(wait);
}
for (freq = 3000; freq > 500; freq -= 10)
{
tone(speaker, freq, time);
delay(wait);
}
for (freq = 500;
freq < 3000;
freq += 10) //
{
tone(speaker, freq, time);
delay(wait);
}
for (freq = 3000;
freq > 500; freq -= 10)
{
tone(speaker, freq, time);
delay(wait);
}
for (freq = 500;
freq < 3000;
freq += 10) //
{
tone(speaker,
freq, time);
delay(wait);
}
for (freq = 3000;
freq > 500;
freq -= 10)
{
tone(speaker, freq, time);
delay(wait);
}
for (freq = 500; freq < 3000; freq += 10)
{
tone(speaker, freq, time);
delay(wait);
}
for (freq = 3000;
freq > 500; freq -= 10)
{
tone(speaker, freq, time);
delay(wait);
}
} if(buf[i] == 'a')
{ digitalWrite(led, LOW); digitalWrite(speaker, LOW);
}
}
}
}
Step 4: Library
For this project you need VirtualWire libraries. In the link below have all the files needed for this project. In video see how this work.
