Smart Air Box Zigbee Formaldehyde / CO2 / VOC / Temperature / Humidity Five In one Function

Air box product specification

Product Name: intelligent air box model:SD0327

function:Detection of indoor air quality, formaldehyde, VOC gas, CO2, temperature, humidity has a certain detection and reference. 5 values are displayed in the graffiti app and can be linked with other graffiti smart home devices(Note: data are for reference only, non professional testing instruments)

Appearance color: white

Material: ABS

Certification: CE / RoHS

Packing list: air box bare metal machine *1, color box *1, instruction manual *1, clip *1

size:

Color box size 9.5 * 9.5 * 4cm

The overall weight of the product is 95g

Bare weight 58G

Outer carton size 53 * 29 * 37cm

Weight of outer box 750g

Packing quantity 100PCS

Parameter table:

Two detection modules are built in the air box

Air quality semiconductor detection module * 1

Temperature and humidity detection module * 1

1,Air quality detection module:

MEMS VOC sensor is used as a module to detect VOC in air. UART communication data output, according to VOC data calculation and equivalent formaldehyde, CO2 output. It has many advantages, such as small size, low power consumption, high sensitivity and fast response.

Detection gas organic volatile gas: ammonia, hydrogen, alcohol, carbon monoxide, methane, propane, glycine, styrene, propylene glycol, phenol, toluene, ethylbenzene, xylene, formaldehyde, etc. Life smoke: cigarette, wood, paper burning smoke, cooking fume and other life odor: life garbage, rotten odor, etc.

Detection concentration:

Cigarette smoke 0.5-5ppm

Alcohol 0.5-100ppm

Hydrogen 1-30ppm

Ammonia 0.8-30ppm

Hydrogen sulfide 0.1-3ppm

Toluene 1-20ppm

The preheating time is 5 seconds to 3 minutes

Response time ≤ 3 seconds

Recovery time ≤ 10 seconds

Working temperature - 20 ℃～ 50 ℃

Working humidity ≤ 95% RH

Storage temperature - 50 ℃～ 60 ℃

Storage humidity ≤ 60% RH

Sensitivity 0.1ppm alcohol

stability

Adaptive ambient temperature and humidity correction

Physical interface

Embedded welding / pin connection

Output data baud rate UART (baud rate 9600bps)

Input voltage 3 ~ 5V DC

Typical value of working current 20mA (5V input)

Standby current < 250ua (5V input)

The service life is more than 5 years

Note: when not in use for a long time or the geographical environment changes, please preheat in clean air for 5-10 minutes, and the module will automatically adjust to the best performance. The start-up measurement after each power-off or sleep needs to warm up for 5 seconds to 3 minutes. The module automatic equalization algorithm will dynamically adjust the warm-up time.

1. The sensor has different sensitivities to different gases, and the module sensitivity only provides reference for alcohol.

2. Input voltage range 3 ~ 5V, wide voltage range, ripple requirement < 50mV

Working principle of air quality detection module

The module detects the polluted gas in the air by measuring the sensor, temperature and humidity

Signal processing and output of pollution data to achieve the detection function of air quality.

●Preheating process

Module power on preheating stable stage, this stage sensor needs to be heated to a stable state, this time depends on the environment

The lower the temperature is, the longer the preheating time is. The module is set to 3 minutes, during which the module will dynamically calculate the preheating time, and the preheating process can be completed in 5 seconds at least, so as to reduce the cost of battery powered products

Power consumption. Although the module shortens the warm-up time, the module will sacrifice sensitivity at this moment

The module preheating time should be extended as far as possible

●Normal measurement

After the module preheating is completed, the module starts to work normally, and collects sensor data continuously, and then keeps it clean with the saved one

The data of clean air are calculated to calculate the environmental pollution value or pollution level.

●Automatic calibration of clean air standard

In order to maintain the high sensitivity of the module and be affected by the sensor drift, the module will automatically update according to the algorithm

The clean air reference value is stored in the memory.

●Saturation correction

Under the condition of air pollution, if the air is filtered through the filter device through the equipment. Air pollution

However, the odor can be filtered through the filter, but the organic volatile gas in the polluted air can not be filtered, such as hydrogenation

However, the sensor can still detect relatively high data, which leads to the inconsistency with the actual feeling of the human body.

In order to avoid this state, an automatic saturation correction algorithm is added to the module to change the output value or level

Don't let the human body feel similar to the actual output

Although saturation correction can bring better correction to a certain extent, it is very stable in the long term

In a given environment (such as a public toilet with heavy odor), saturation correction will cause the output data to be clean. all

However, considering the particularity of the environment, saturation correction algorithm is still introduced.

2,Temperature and humidity detection module

Digital temperature and humidity sensor is a kind of temperature and humidity composite sensor with calibrated digital signal output. It uses special digital module acquisition technology and temperature and humidity sensing technology to ensure that the product has high reliability and excellent long-term stability.

The sensor consists of a capacitive humidity sensor and an NTC temperature sensor.

Exceeding the recommended operating range may result in temporary drift signals up to 3% RH. After returning to normal operating conditions, the sensor

It will slowly return to the calibration state. To speed up the recovery process, see recovery processing. Long time under abnormal working conditions

The use will accelerate the aging process of the product.

Avoid long-term exposure to condensation and dryness, as well as the following environments.

A. Salt spray;

B. Acidic or oxidizing gases, such as sulfur dioxide, hydrochloric acid;

Recommended storage environment

Temperature: 10 ~ 40 ℃

Humidity: below 60% RH.

Effects of exposure to chemicals

The sensing layer of capacitive humidity sensor will be interfered by chemical vapor, and the diffusion of chemical substances in the sensing layer may lead to the interference

The measured value drifts and the sensitivity decreases. In a pure environment, pollutants are released slowly. Restoration as described below

Reprocessing will accelerate this process. High concentration of chemical pollution will lead to the complete damage of sensor sensing layer.

Temperature effect

The relative humidity of a gas depends largely on its temperature. Therefore, when measuring humidity, humidity sensing should be ensured as far as possible

It works at the same temperature. If the PCB is shared with the heat releasing electronic components, it should be installed as far as possible

The sensor is far away from the electronic components and installed under the heat source, while maintaining good ventilation of the housing. In order to reduce the heat conduction, the copper coating of sensor and other parts of printed circuit board should be as minimum as possible, and a gap should be left between them.

Light effects

Long time exposure to sunlight or strong ultraviolet radiation will degrade the performance.

Recovery processing

Sensors placed in extreme working conditions or in chemical vapor can be restored to their original calibration state by the following procedures

Status. Keep for 2 hours (drying) at 45 ℃ and < 10% RH, and then keep for more than 5 hours at 20-30 ℃ and > 70% RH.