ENS160+AHT21 Carbon Dioxide CO2 eCO2 TVOC Air Quality and Temperature Humidity Sensor User Manual

1. Introduction

The ENS160 is a digital multi-gas sensor specifically designed for indoor air quality monitoring. It is capable of detecting a variety of gases and volatile organic compounds (VOCs), including toluene, hydrogen, ethanol, NO2, and ozone. This air quality sensor is ideal for applications in home and building automation, consumer goods, electrical appliances, and air purification systems. When combined with the AHT21, it also provides temperature and humidity readings, offering a comprehensive environmental monitoring solution.

Figure 1: Integrated ENS160 and AHT21 Sensor Module

2. Key Features

• Detection of reducing (VOC) and oxidizing gases (such as NO2).
• MOX supports up to 4 independent gas sensors.
• Integrated sensor measurement and heater drive control.
• Integrated pre-calibrated sensor fusion and automatic baseline correction algorithm.
• Multiple IAQ outputs (TVOC, eCO2, AQL).
• I2C and SPI interface options.
• Warm-up time: Less than 1 minute.
• Start-up time: Less than 1 hour.
• High resistance to siloxane and humidity.

3. Benefits

• Ease of Use: Provides selection of multi-standard air quality signals.
• Easy Integration: No complex software library is required, minimizing impact on the host CPU.
• Fast Response: Ideal for systems requiring quick environmental data updates.
• Reliability: Safe for use in daily necessities and offers high resistance to common environmental interferences like siloxane and humidity.
• Flexible Design: Suitable for robust and adaptable product designs.

4. Specifications

Figure 2: Sensor Module Dimensions

5. Setup and Wiring

The ENS160+AHT21 module features multiple pins for power, ground, and communication interfaces (I2C and SPI). Refer to the pinout diagram below for proper connections.

Figure 3: Sensor Module Pinout

5.1 Pin Descriptions

• VIN: Input voltage (typically 5V, regulated down to 3.3V internally).
• 3V3: 3.3V regulated output or direct 3.3V input.
• GND: Ground connection.
• SCL/SCLK: I2C Clock / SPI Clock.
• SDA/MOSI: I2C Data / SPI Master Out Slave In.
• ADD/MISO: I2C Address Select / SPI Master In Slave Out.
• CS: Chip Select for SPI communication.
• INT: Interrupt pin.

5.2 Connection Guidelines

1. Connect VIN or 3V3 to your microcontroller's power supply (e.g., 5V or 3.3V).
2. Connect GND to the common ground of your system.
3. For I2C communication, connect SCL to your microcontroller's SCL pin and SDA to your microcontroller's SDA pin. The ADD pin can be used to select the I2C address if multiple devices are on the bus.
4. For SPI communication, connect SCLK, MOSI, MISO, and CS to the corresponding SPI pins on your microcontroller.
5. Ensure all connections are secure and correctly oriented to prevent damage to the module or host device.

6. Operating Instructions

Once the module is correctly wired and powered, it will begin its initialization sequence:

• Warm-up: The sensor requires less than 1 minute to warm up and stabilize its internal components. During this period, readings may not be accurate.
• Start-up: Full calibration and baseline correction algorithms will complete within approximately 1 hour. For optimal accuracy, especially for eCO2 and TVOC readings, allow the sensor to operate for at least one hour in its target environment before taking critical measurements.

After the start-up phase, the module will continuously provide Indoor Air Quality (IAQ) outputs, including Total Volatile Organic Compounds (TVOC), equivalent Carbon Dioxide (eCO2), and Air Quality Level (AQL), along with temperature and humidity data from the AHT21 sensor. These values can be read via the selected communication interface (I2C or SPI).

7. Maintenance

The ENS160+AHT21 sensor module is designed for low maintenance. To ensure optimal performance and longevity:

• Keep Clean: Avoid dust and debris accumulation on the sensor surface. Use a soft, dry brush or compressed air if cleaning is necessary. Do not use liquids or abrasive materials.
• Environmental Conditions: Operate the sensor within its specified operating temperature and humidity ranges (-40℃ to +85℃, 5% to 95% RH). Exposure to extreme conditions outside these ranges can affect performance and lifespan.
• Storage: When not in use, store the module in a dry, anti-static environment, preferably in its original packaging.
• Avoid Contaminants: Protect the sensor from direct exposure to high concentrations of chemicals, solvents, or strong odors, which can temporarily or permanently affect its readings.

8. Troubleshooting

If you encounter issues with your ENS160+AHT21 sensor module, consider the following:

• No Readings/Incorrect Readings:
  • Verify all wiring connections (power, ground, and communication lines) are correct and secure.
  • Check the power supply voltage to ensure it is within the specified range (1.71V to 1.98V for VDD, or 3.3V/5V for VIN).
  • Ensure your microcontroller's code is correctly configured for the chosen communication interface (I2C address or SPI settings).
  • Allow sufficient warm-up and start-up time as described in Section 6.
  • Ensure the sensor is not exposed to sudden, drastic changes in environmental conditions or high concentrations of interfering gases.
• Communication Errors:
  • Double-check I2C addresses or SPI chip select lines.
  • Ensure pull-up resistors are correctly implemented for I2C lines if required by your setup.

9. User Tips

No specific user tips were available from reviews or Q&A for this product at the time of manual creation. However, general best practices for environmental sensors include:

• Stable Environment: For the most accurate readings, place the sensor in a location with stable airflow and temperature, away from direct heat sources, vents, or drafts.
• Software Libraries: While not strictly required, using a well-tested software library for the ENS160 and AHT21 can simplify integration and data interpretation.
• Data Logging: Implement data logging to track environmental changes over time and identify trends.

10. Warranty and Support

For warranty information, technical assistance, or further support regarding your ENS160+AHT21 sensor module, please refer to the seller's policies or contact EYEWINK customer service directly through their official channels.