Integrating Temperature, Light, and Infrared Sensors in PHP IoT Projects

With the rapid development of IoT technology, many devices need network connectivity for remote control and data collection; sensors are core components, and integrating them into PHP projects requires specific code to read and process their data.

1. Temperature‑Humidity Sensor – Connect the sensor to a serial port, configure the port with a terminal tool, then use the PHP dio extension to read data. Example code:

<code>&lt;?php
$fd = dio_open('/dev/ttyUSB0', O_RDWR | O_NOCTTY | O_NONBLOCK);
 dio_fcntl($fd, F_SETFL, O_SYNC);
 if ($fd) {
     $data = dio_read($fd, 1024);
     echo $data;
     dio_close($fd);
 }
?&gt;</code>

The device path /dev/ttyUSB0 and flags O_RDWR | O_NOCTTY | O_NONBLOCK configure the serial connection. After reading, parse the hexadecimal payload (e.g., "0xaa 0x01 0x08 0x1e 0x45 0x00 0x46 0xaa" ) to extract temperature and humidity:

<code>&lt;?php
$data = "\xaa\x01\x08\x1e\x45\x00\x46\xaa";
$data = bin2hex($data);
$len = strlen($data);
if ($len >= 18 && $data[0] == 'aa' && $data[1] == '01' && $data[$len-1] == 'aa') {
    $temperature = hexdec($data[3].$data[4]) / 10;
    $humidity    = hexdec($data[5].$data[6]) / 10;
    echo "Temperature: $temperature C\n";
    echo "Humidity: $humidity%\n";
}
?&gt;</code>

2. Light Sensor – The sensor outputs an analog voltage; on a Raspberry Pi it can be read via the bcm2835 extension. Example code initializes the library, configures GPIO 18 as input, sets PWM parameters, and continuously reads the analog value:

<code>&lt;?php
include('bcm2835.php');
if (!bcm2835_init()) {
    die('Unable to initialize BCM2835 library.\n');
}

bcm2835_gpio_fsel(18, BCM2835_GPIO_FSEL_INPT);
bcm2835_pwm_set_clock(BCM2835_PWM_CLOCK_DIVIDER_512);
bcm2835_pwm_set_mode(0, 1, 1);

while (true) {
    $value = bcm2835_analog_read(0);
    bcm2835_pwm_set_data(0, $value / 4);
    bcm2835_delay(500);
}

bcm2835_close();
?&gt;</code>

The functions bcm2835_init , bcm2835_gpio_fsel , bcm2835_pwm_set_clock , bcm2835_pwm_set_mode , bcm2835_analog_read , bcm2835_pwm_set_data , and bcm2835_delay handle initialization, GPIO configuration, PWM control, analog reading, and timing.

3. Infrared Sensor – Used for detecting hot spots or remote‑control commands. After wiring the IR receiver to a microcontroller, PHP can parse the received binary string. Example:

<code>&lt;?php
$data = "01011110111010011101000010101010";
if (substr($data,0,8) == "01011110" && substr($data,8,8) == "11101001" && substr($data,16,8) == "11010000") {
    $payload = substr($data,24);
    $command = bindec(substr($payload,0,8));
    $param   = bindec(substr($payload,8,8));
    switch ($command) {
        case 0x01: // turn on light
            break;
        case 0x02: // turn off light
            break;
        case 0x03: // adjust brightness
            break;
        default:
            break;
    }
}
?&gt;</code>

The substr function extracts portions of the binary string, and bindec converts them to decimal values for further processing.

Conclusion – By using appropriate PHP extensions and handling different communication protocols (serial, analog, IR), developers can integrate various sensors into IoT projects to achieve comprehensive environment monitoring and intelligent control.