AM2302 Temperature Humidity Composite Sensor

1. Overview:

The AM2302 is a combined temperature and humidity sensor with calibrated digital signal output. It applies specialized digital module acquisition technology and temperature-humidity sensing technology, ensuring extremely high reliability and excellent long-term stability.

2. Working Principle:

The sensor consists of a capacitive humidity-sensing element, a high-precision temperature-sensing element, and a high-performance 8-bit microcontroller. Calibration coefficients are stored in the microcontroller as a program, which are called during the processing of detected signals inside the sensor.

3. Supply Voltage:

3.3 - 6V

4. Signal Transmission:

• Adopts a single-wire serial interface with 40-bit data transmission (MSB first).
• Communication time: Approximately 5ms per cycle.
• Data format: 16-bit humidity data + 16-bit temperature data + 8-bit checksum.

5. Measurement Range and Accuracy:

• Humidity:
  • Range: 0 - 100% RH
  • Accuracy: 2 - 5% RH
• Temperature:
  • Range: -40 - 80°C
  • Accuracy: ±0.5°C

6. Power Consumption:

2.5mA max (during conversion, i.e., when requesting data)

7. Dimensions:

• Main body: 27mm x 59mm x 13.5mm
• Cable length: 23cm

8. Response Time:

• The temperature and humidity data read by the host from AM2302 is always the previous measurement value.
• When the interval between two measurements is long, read twice consecutively and take the second value as the real-time data.
• Minimum interval between two reads: 2 seconds.

9. Interface Description:

• Typically includes 3 - 5V power pin, data pin, and ground pin.
• Although it uses a single wire for data transmission, it is incompatible with the Dallas 1 - wire bus.
• For multiple sensors, each must have its independent data pin.
• The sensor internally has a 5.1kΩ pull-up resistor connecting VCC and data pin, so external pull-up resistors are generally unnecessary.