DHT11 Humidity and Temperature Sensor is a basic, ultra low-cost digital temperature and humidity sensor. It uses a capacitive humidity sensor and a thermistor to measure the surrounding air and spits out a digital signal on the data pin (no analog input pins needed). It’s fairly simple to use but requires careful timing to grab data. Specifications : Working Voltage : 3 to 5V DC Working Current : 2.5mA max current use during conversion (while requesting data) Humidity Range : 20-80% humidity; ±5% accuracy Temperature Range : -20°C to 50°C temperature; ±2°C accuracy No more than 1 Hz sampling rate (once every second) Dimensions (W X L) : 18.03mm x 29.21 mm