SPECIFICATION Product Name: Single Beam NDIR CO2 Sensor Module Item No.: CM1106LS Version: V0.3 Date: May 29th, 2020

Single Beam NDIR CO2 Sensor Module CM1106LS Applications ▪ HVAC industry ▪ IAQ monitor ▪ Air purifier ▪ Automotive ▪ IoT devices ▪ Plant growth Description CM1106LS is a single beam NDIR CO2 sensor module, based on non-dispersive infrared (NDIR) technology, which can detect CO2 concentration of indoor air. With high accuracy, high stability, small size, it is widely used for ventilation system, air purifier, air conditioner, HVAC transmitter, IAQ monitor, etc. ▪ NDIR technology with independent intellectual property ▪ High accuracy, long term stability, long life (>10years) ▪ Temperature calibration...

Note 1: In normal IAQ applications, accuracy is defined after minimum three (3) ABC periods of continuous operation with ABC on. Some industrial applications do require maintenance. Contact Cubic for further information. Note 2: Specification is referenced to certified calibration mixtures. Uncertainty of calibration gas mixtures (±2% currently) is to be added to the specified accuracy for absolute measurement.

Dimensions and Connector 1. Dimensions (Unit mm, tolerance ±0.2 mm) Power supply output (+3.3V/100mA) Power supply input (4.5V-5.5V) Power supply input (GND) UART-RX (Receiving)/I²C data, compatible with 3.3V and 5V communication UART-TX (Sending)/I²C clock, Compatible with 3.3V communication Output mode exchange: High level or floating is UART communication mode, low level is I²C communication mode Manual calibration

Application scene: UART_TTL serial port output Application scene: 3.3V- 5V Level Shift

Description of Calibration Auto Calibration: Rough installing and influence of transportation might result in reducing of sensor measuring accuracy and baseline drift, sensor will correct the drift by the built-in self-correcting logic. Powering on the sensor for 7 days continuously, it will record the lowest CO2 concentration measurement value during the 7 days, which will be regarded as baseline (400ppm) when sensor do auto calibration after the 7 days working. In order to ensure correct auto calibration, please make sure working environment of the sensor can reach to outdoor fresh air level...

PWM and Alarm Output PWM cycle: 1004ms Positive pulse width: 0-5000: (PPM/5) + 2ms CO2 concentration detection value: 5000ppm range: (PWM Positive pulse width -2) *5 PWM output schema: Alarm Output If the CO2 concentration rises up to more than 1000ppm, the alarming will be triggered and output high level. When the CO2 concentration goes down to below 800ppm, the alarming will stop and output low level. Note Connect the pin of PWM to the oscilloscope. Add a pull-up resistor around 5K-10K between the pin of PWM and power supply.

Product Installation 1. In order to ensure airflow diffusion into the sensor inner, make sure the minimum distance between the area of waterproof filter and the other components is 1.5 mm, otherwise, quick response time of the sensor will be effected. Reference as below: 2. To avoid the influence of stress on sensor, please soldering by hand as much as possible when mounting the sensor to the PCB. Reference as below:

1).The data in this protocol is all hexadecimal data. Example: “46” for decimal [70]. 2). Baud rate: 9600, Data Bits: 8, Stop Bits: 1, Parity: No, Flow control: No. 3). [x x] is for single-byte data (unsigned, 0-255); for double data, high byte is in front of low byte. Sending format of test software:

4.1 Read Measured Result of CO2 Send: 11 01 01 ED Response: 16 05 01 DF1- DF4 [CS] Function: Read measured result of CO2 (Unit: ppm) Note: CO2 measured result = DF1*256+DF2 DF3 DF4 is reserved Example: Response: 16 05 01 02 58 00 00 8A Explanation: Hex is converted to decimal: 02 is 02; 58 is 88 , so CO2 concentration =02*256+88 = 600ppm 4.2 Open/Close ABC and Set ABC Parameter Send: 11 07 10 DF1 DF2 DF3 DF4 DF5 DF6 CS Response: 16 01 10 D9 Explanation: DF1: reserved, default 100 (0x64) DF2: open/close auto calibration (0: open; 2: close) DF3: calibration cycle (1-30 days optional, default is...

Response: 16 01 10 D9 4.2.3 Change the Calibration Cycle The calibration cycle is 7 days by default. For example, if you want to change the calibration cycle to 10 days, you should set the DF3=10. Example: Send: 11 07 10 64 00 0A 01 90 64 75 Response: 16 01 10 D9 4.3 Calibration of CO2 Concentration Send: 11 03 03 DF1 DF2 CS Response: 16 01 03 E6 Function: Calibration of CO2 concentration Note: 1. Calibration target value = DF1*256+DF2 Unit: PPM, range (400-1500ppm) 2. Before calibration, please make sure CO2 concentration in current ambient is calibration target value. Keeping this CO2 concentration...

1. Timing Diagram Introduction 1.1 Common Description a. This protocol is based on standard I2C timing sequence, the clock frequency is 10kHz～400kHz. b. Use big-endian format, the most significant bit to be sent first. 1.2 I2C Sequence Diagram Introduction Parameter fSCL (SCL clock frequency) tHD.STA (hold time of the starting bit) tSU.STA (setup time of the starting bit) tHD.DAT (hold time of the data) tSU.DAT (setup time of the data ) tSU.STO (setup time of the stop bit) Note: SCL clock frequency is generated by the master device with the range 10khz～400khz. Picture1: I2C clock introduction...

The meaning of the symbol in picture 1.2 and picture 1.3: S: start condition SA: slave address W: write bit R: read bit A: acknowledge bit ~A: not acknowledge bit D: data, each data is 8bit P: stop condition Shadow: The signal generated from the master device No Shadow: The signal generated from the slave device 1.4 Timing Diagram Picture 1.4: The address byte sent from the master device Picture 1.5: The master device read a byte from the slave device 1.5 Notes The performance of the MCU which is used in the sensor is not very high. If you use I/O port to simulate I²C master device, it is suggested...

Example: The master device reads some data: Read 3 bit. 0x01 0x03 0x20 0x01 0xDB CO2 measuring result = (0x03 0x20) hexadecimal = (800) decimal = 800 ppm Status bit: 0x01 means working normally