SPECIFICATIONS

• Carbon monoxide CO 1 – 1000ppm

• Nitrogen dioxide NO2 0.05 – 10ppm

• Ethanol C2H5OH 10 – 500ppm

• Hydrogen H2 1 – 1000ppm

• Ammonia NH3 1 – 500ppm

• Methane CH4 >1000ppm

• Propane C3H8 >1000ppm

• Iso-butane C4H10 >1000ppm

CJMCU-1100 MS1100
This module is a high-performance, high-precision module for detecting a variety of volatile gases in the air. It can detect volatile gases above 0.1PPM in air, and the chip has fast response speed, more accurate data and small volume. Mainly used in home air quality testing, ambient air testing, range hood ventilation fans. Module measurement range: 0~1000PPM gas qualitative detection.

Instructions for use:
power supply voltage: +5V
AOUT : Analog output, the voltage value corresponding to the amount of gas detected by the chip changes, the microcontroller can be directly connected using the ADC.
DOUT: Digital output, the result of comparing the output voltage values of AOUT and adjustable resistors. Output semaphores 0 and 1.
Adjust the adjustable resistance of the module. When the voltage of the adjustable resistor output is less than AOUT, DOUT outputs a high level and the LED light is on; otherwise, DOUT outputs a low level and the LED is off.
variable resistance: 4K
Clean air voltage <1V
response speed <5S
Working temperature: -10 degrees Celsius ~ 60 degrees Celsius,
Working humidity: 90% RH


Precautions for use of the module: 
When needed, the module needs to be warmed up for 3-5 minutes before making relevant measurements.
Connect to the microcontroller:
VCC - 5V of single chip microcomputer
GND - GND A of the microcontroller
OUT - AD input pin of the microcontroller
DOUT - any available pin of the microcontroller

CCS811 CJMCU - 8128 + HDC1080 (SI7021) + BMP280
Features:
CCS811 CJMCU - 8128 + HDC1080 (SI7021) + BMP280
Carbon monoxide CO VOCs pressure sensor on temperature and humidity of gas
Triad sensor
Module size: 18 mm * 21 mm
Power supply: 3.3 V
CJMCU - 8128 - a gas sensor system on a chip + temperature and humidity sensor, a low-power sensor technology to detect the indoor volatile organic compounds (VOCs).
CJMCU8118 onboard CCS811 structure sketch we can see that this is not a simple sensor, it has integrated the internal MCU, make this kind of sensor has the on-board processing ability, in the case of without the host intervention, can provide equivalent carbon dioxide level or total volatile organic compounds (TVOC) index. At the same time, with the use of separate gas sensor and MCU solution, CCS811 can save equipment cost and as much as 60% of the plate area.
HDC1080 has a temperature sensor of low power consumption, high precision digital humidity sensor
DC1080 is a digital humidity sensor with integrated temperature sensor, it can provide excellent measurement precision with ultra-low power consumption. HDC1080 support wide working voltage range, and compared the competitive solution, the device can be used for all kinds of common provides low cost and low power consumption advantages. Humidity and temperature sensors have been the factory calibration.
Accuracy of plus or minus 2% relative humidity (typical)
Temperature accuracy of + / - 0.2 ° C (typical)
High humidity has excellent stability
14 measurement resolution
Sleep patterns of current of 100 nA

CJMCU-30
The CJMCU-30 digital gas sensor SGP30 opens up new possibilities for indoor air quality measurements. The SGP30 is a metal oxide gas sensor with multiple sensing elements on a single chip that provides detailed information on air quality. These sensing elements have the ability to withstand fouling gases in practical applications, resulting in excellent long-term stability and low drift. The I2C interface, as well as a waterproof and dustproof protective film, make SGP30 easy to integrate into a variety of applications, such as home appliances and smart home devices.

VCC: 3V-5V

HDC1080
Operating Voltage: 2.7V-5.5V
Average Supply Current: 1 SPS, 11-bit Relative Humidity Measurement: 710 nA
1 SPS, 11-bit Relative Humidity and Temperature Measurement: 1.3 µA
Sleep Mode Current: 100 nA
Measurement Accuracy: Relative Humidity Accuracy: ±2% (Typical)
Relative Temperature Accuracy: ±0.2°C (Typical)
Measurement Resolution: 14-bit
Communication Interface: I2C
Pin Definitions
GND: Ground
SCL: I2C Serial Clock Line
SDA: I2C Serial Data Line
Vcc: Power Supply (+)