DHT22 (AM2302) Temperature & Humidity

Protocol & Timing

The DHT22 uses a custom single-wire serial transmission protocol over GPIO 13. Readings are acquired non-blockingly at 1-second intervals.

Measurement Tolerances

• Temperature Range: -40°C to +80°C (±0.5°C accuracy)
• Humidity Range: 0% to 100% RH (±2–5% accuracy)

Implementation & Safeguards

temperature = dht.readTemperature();
humidity = dht.readHumidity();

if (isnan(temperature) || isnan(humidity)) {
    lcd.clear();
    lcd.setCursor(0, 0);
    lcd.print("Sensor Error");
}

The firmware validates reading integrity using isnan() checks to gracefully notify users on the LCD if sensor wires disconnect.