ZE15-CO Sensor Tests (CircuitPython)

Overview

This repository contains CircuitPython scripts (programs) for testing the Winsen ZE15-CO carbon monoxide sensor using UART communication on a Raspberry Pi Pico.

Currently included:

• Initiative Upload Mode Test - Reads CO concentration automatically sent by the sensor every second.
• Question and Answer Mode Test - Sends requests to the sensor and reads responses.

Datasheet: ZE15-CO Official Datasheet

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Hardware Setup

• Sensor TX - Pico GP1 (RX)
• Sensor RX - Pico GP0 (TX)
• Sensor GND - Pico GND
• Sensor VCC - Pico 5V

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UART Communication Protocol

The ZE15-CO sensor communicates using a UART (serial) interface at:

• Baud Rate: 9600
• Data Bits: 8
• Stop Bits: 1
• Parity: None

It supports two communication modes: Initiative Upload Mode and Q&A Mode.

Initiative Upload Mode (Default)

• The sensor automatically sends a 9-byte data packet every 1 second.
• No commands are needed from the microcontroller.
• Each packet contains the CO concentration value in ppm.

Initiative Upload Mode Data Packet Format (9 bytes per packet)

Byte0   Byte1   Byte2   Byte3   Byte4   Byte5   Byte6   Byte7   Byte8
0xFF    0x04    0x03    0x01    [HIGH]  [LOW]   0x13    0x88    [CHK]

Byte	Description
0xFF	Start byte
0x04	Gas type (CO)
0x03	Unit (ppm)
0x01	Number of decimal places (fixed at 0.1 ppm)
[HIGH]	CO Concentration High Byte
[LOW]	CO Concentration Low Byte
0x13	Full range high byte (fixed)
0x88	Full range low byte (fixed)
[CHK]	Checksum

CO Concentration Formula:
CO ppm = (HIGH * 256 + LOW) * 0.1

Example:

Received Data: ['0xFF', '0x04', '0x03', '0x01', '0x00', '0x05', '0x13', '0x88', '0x58']

• HIGH = 0x00 (0 in decimal)
• LOW = 0x05 (5 in decimal)
• CO ppm = (0 * 256 + 5) * 0.1 = 0.5 ppm

Question & Answer (Q&A) Mode

• The microcontroller sends a command request to the sensor.
• The sensor responds with a CO concentration reading.

Q&A Mode Request Data Packet Format (9 bytes)

0xFF  0x01  0x86  0x00  0x00  0x00  0x00  0x00  [CHK]

Q&A Mode Response Data Packet Format (9 bytes)

0xFF  0x86  [HIGH]  [LOW]  0x00  0x00  [HIGH]  [LOW]  [CHK]

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Usage

1. Install CircuitPython on the Raspberry Pi Pico. (Guide)
2. Copy code.py to the Pico.
3. Open a serial terminal (Mu Editor, Thonny, or screen).
4. View CO ppm readings which update every second.