User Manual: Tuya Smart Air Quality Sensor Guard

1. Introduction

The Tuya Smart Air Quality Sensor Guard (Models MT15 and MT29) is a versatile 15-in-1 environmental monitoring device designed to provide real-time insights into your indoor air quality. It detects and displays 11 key environmental parameters, including Carbon Dioxide (CO2), Carbon Monoxide (CO), Formaldehyde (HCHO), Total Volatile Organic Compounds (TVOC), Particulate Matter (PM0.3, PM1.0, PM2.5, PM10), Temperature, Humidity, and the Air Quality Index (AQI).

The device features a 2.8-inch TFT display for clear readings and integrates with the Tuya Smart WIFI APP for remote monitoring, historical data viewing, and intelligent scene automation. It also includes practical functions such as an alarm clock, timer, and stopwatch.

The MT15 model utilizes high-quality infrared and laser sensors for precise and accurate data, while the MT29 model uses semiconductor sensors (except for PM detection which uses infrared sensors) offering a cost-effective solution with multi-functional capabilities. Note that while the functionality is the same, the sensor types differ, with MT15 being the high-end version. The actual products have completed screen upgrades, so please refer to the product SKU pictures for the latest display.

This device is suitable for various application scenarios including family homes, offices, schools, cars, gyms, and hotels.

Image: The 15-in-1 Air Quality Detector in operation.

2. Safety Information and Precautions

• This product has a built-in lithium battery; please use a standard DC-5V charger.
• Ensure the air inlet and outlet are not blocked during operation to prevent numerical deviation.
• Avoid frequent use in dusty environments with poor air quality to prolong service life.
• Do not use this device in high temperature, high humidity, dirty places, or near strong magnetic fields to prevent inaccurate values or internal circuit failure.
• The device operates within a temperature range of -10°C to 50°C. Store between -20°C and 55°C. Extreme temperatures may cause equipment failure.
• Protect the device from exposure to rain or moisture to avoid malfunctions or risks to the display screen, battery, case, and circuit.
• Do not insert sharp objects (e.g., pins) into the air inlet, outlet, or charging port to prevent damage.
• Upon initial unboxing, if an alcohol odor is present (from factory cleaning), place the device in a well-ventilated area for 1-2 hours until data normalizes.
• TVOC sensors may be affected by smoke, alcohol, formaldehyde, perfume, and other odor interference. Data will return to normal after a period.
• This product provides detection and alarm functions but cannot prevent dangerous substance leakage. The manufacturer does not assume responsibility for accidents caused by such leakage.

3. Package Contents

The product package includes the following items:

• 1 x Air Quality Detector (MT15 or MT29 model)
• 1 x Type-C Data Cable
• 1 x User Manual (this document)

Image: What you will receive in the package.

4. Product Overview

The Air Quality Sensor Guard features a compact design with a 2.8-inch TFT color HD display, providing clear and real-time readings of various air quality parameters. The device is equipped with a multi-sensor structure, utilizing infrared, laser, and semiconductor sensors for comprehensive detection.

Image: Front and side view of the Air Quality Detector.

4.1. Display Modes

The device supports multiple display modes to show different information:

• Display Mode 1 (Fig A): Shows Date & Time along with 11 air quality parameters.
• Display Mode 2 (Fig B): Shows Date & Time, Alarm Clock, and Timer.
• Calibration Mode (Fig C): Indicates when the device is undergoing a 120-second calibration process.

Image: Different display modes of the device (Fig A, B, C).

4.2. Physical Features

• Innovative Design: Bilateral ventilation with large holes for accurate and quieter measurements.
• Large Capacity Battery: Built-in 2000mAh Li-Po battery, charged via DC5V Type-C port. Offers 5 hours of bright screen standby or 7 hours of screen-off standby.
• Wall Hanging Function: Convenient for use anywhere with integrated wall-hanging holes on the back.

Image: Product details highlighting design, battery, and wall mount.

5. Specifications

6. Setup

6.1. Initial Charging

Before first use, fully charge the device. A full charge takes approximately 3-4 hours and provides 6-7 hours of operation. Use the provided Type-C USB cable and a DC5V/1A charger.

6.2. Initial Power On and Calibration

Press and hold the Power button for more than 3 seconds to power on the device. After a 60-second countdown, the device will begin detecting and displaying air quality parameters. For the most accurate data, allow the device to operate continuously for 24 hours after initial power-on, especially after inserting the USB charging cable.

The device also features a 120-second parameter calibration mode, which can be initiated via key operation (see Section 7.1).

Image: Device displaying "Calibrating".

6.3. Tuya Smart APP Installation and WiFi Pairing

To utilize remote monitoring and smart features, install the Tuya Smart APP and pair your device:

1. Install the APP: Search for "Tuya Smart" in your mobile phone's app store ("Application Market") or scan the QR code provided in the manual (see Fig A in Section 4.1). Install the app and register an account.
2. Initiate Pairing Mode: Within 2 minutes of turning on the device, or by pressing the Power button 5 times continuously, the WiFi symbol on the device will flash quickly, indicating it's in pairing mode.
3. Open APP and Add Device:
   • Open the Tuya Smart APP and click "Add Device" (Fig 4).
   • The app will search for nearby WiFi devices (Fig 5).
   • Once your device is found, click "Add" again.
   • Enter your WiFi network name and password (Fig 6).
   • Click "Next" to complete the pairing connection (Fig 7 & Fig 8).
   • Click "Finish". The WiFi symbol on the device will stop flashing once connected successfully (Fig 9).

Image: Tuya Smart APP setup steps (Fig 4-7).

Image: Tuya Smart APP setup steps (Fig 8-11).

7. Operating Instructions

7.1. General Key Operations (Power Button)

• Press and hold for >3 seconds: Power on/off.
• Short press 1 time:
  • In Display Mode 1 (Fig A): Switch temperature unit between Celsius (°C) and Fahrenheit (°F).
  • In Display Mode 2 (Fig B): Turn on/off the timer function.
• Short press 2 times:
  • In Display Mode 1 (Fig A): Turn on/off the buzzer.
  • In Display Mode 2 (Fig B): Clear the timer or stopwatch. If an alarm is sounding, this prioritizes turning off the alarm sound.
• Short press 3 times: Enter/exit Display Mode 2 (Time & Alarm Clock & Timer/Stopwatch display).
• Short press 4 times: The instrument enters 120 seconds parameter calibration.
• Short press 5 times: The device enters WiFi pairing state/resets WiFi. The WiFi icon will blink with a delay of about 5 seconds.

7.2. Tuya Smart APP Remote Monitoring

Once successfully linked to WiFi, the Tuya Smart APP allows for comprehensive remote control and monitoring:

• Real-time Monitoring: View 11 air parameters in real-time.
• Historical Data: Access historical curve data for 10 air parameters (CO2, HCHO, TVOC, CO, PM2.5, PM10, PM1.0, PM0.3, TEMP, HUMI) by clicking "Statistical curve" in the app (Fig 9, then Fig 13). You can view data by day, month, or year.
• Intelligent Scene Automation: Create smart scenes and automations based on air quality readings.
• Synchronization: Date and time parameters are synchronized with the app (24-hour system).

Image: Tuya Smart app interface for monitoring and control.

7.3. Alarm Settings (via APP)

You can customize alarm thresholds and settings through the Tuya Smart APP (Fig 9):

• Parameter Alarm Thresholds: Set custom alarm values for CO2, CO, PM2.5, and HCHO (Fig 15). Default thresholds are: CO2 > 1500ppm, CO > 200ppm, PM2.5 > 100ug/m³, HCHO > 0.08mg/m³. Exceeding these triggers three rapid buzzer alarms with one-second intervals.
• Alarm Clock: Set up to three alarm clocks (Fig 10, Fig 12). The alarm clock is a 12-hour system. When an alarm triggers, it sounds for 30 seconds, and the alarm clock symbol will flash. Press the Power button twice to cancel the alarm sound.
• Alarm Sound Switch: Turn the alarm sound on/off (Fig 14).
• Device Sleep Time: Set the device's hibernation time (Fig 16).

Image: Tuya Smart APP settings for alarms and timers (Fig 12-16).

7.4. Timer Function

• Timer Display: In Display Mode 1, short press the Power button once to switch to Display Mode 2, which shows the timer.
• Timer Timing: In Display Mode 2, short press the Power button once to start positive timing. The maximum time is 9 hours, 59 minutes, 59 seconds. Press once to pause, press again to continue, and press twice to cancel.
• Setting the Timer: In Display Mode 2, long press the Power button for 1 second. The 'H' (hours) bit of the stopwatch will flash. Short press the Power button (1-9 times) to select the number of hours. Long press for 1 second again, and the 'Min' (minutes) bit will flash, allowing you to set minutes and seconds similarly. If no action is taken for 6 seconds, the setting is complete.

8. Environmental Pollution Index Reference

The Air Quality Index (AQI) and other parameter values are color-coded on the device display to indicate air quality levels:

Note: Initial alarm values are defaults and can be customized via the APP. The color indication on the device (Green/Orange/Red) will change based on these updated settings (refer to Fig A/B/C for examples).

9. User Tips

• For optimal accuracy, ensure the device has been running for at least 24 hours after initial setup or after a factory reset.
• Regularly check the device's placement to ensure air inlets and outlets are unobstructed.
• Utilize the Tuya Smart APP to set personalized alarm thresholds for specific parameters to suit your environment and sensitivity.
• The device can be wall-mounted for convenient, continuous monitoring in a fixed location.

10. Troubleshooting

• Abnormal or High Data Readings: If the data appears unusually high or abnormal, turn off the device and then turn it back on. Connect the USB cable, place the device near a window in a well-ventilated environment, and allow it to operate for 24 hours. This process will clear internal data to zero and normalize readings.
• TVOC Sensor Interference: The TVOC sensor can be temporarily affected by strong odors such as smoke, alcohol, formaldehyde, or perfumes. If this occurs, the readings will return to normal after a period once the interfering substance dissipates.
• Device Not Pairing with WiFi: Ensure the device's WiFi symbol is flashing quickly (indicating pairing mode). Double-check your WiFi network name and password in the Tuya Smart APP. If issues persist, try resetting the device's WiFi by pressing the Power button 5 times continuously.
• Inaccurate Readings: Ensure the device is not placed in dusty, high-temperature, high-humidity, or strong magnetic field environments. Also, verify that the air inlets and outlets are not blocked.

11. Warranty and Support

This product comes with a 1-year warranty period from the date of purchase.

For further detailed instructions, technical support, or warranty claims, please refer to the comprehensive user manual available in PDF format. You can access the PDF manual here.

Please note the disclaimer: This product has detection and alarm functions but cannot prevent dangerous substances leakage. The manufacturer does not assume responsibility for accidents caused by such leakage.