Overview

This folder contains two Arduino (.ino) files used to work with an MQ-4 methane gas sensor and an Arduino Uno.

The sensor readings collected using these programs are part of this dataset:
https://doi.org/10.6084/m9.figshare.30783827

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File 1: gas_sensor_warming.ino

• Warms up the MQ-4 sensor
• Finds the clean-air baseline value (R0)

Use

• Run once when setting up the sensor
• Run again only if the sensor or wiring changes

Output

• Raw sensor values
• Sensor resistance
• Final stable R0 value (shown in Serial Monitor)

Note down the R0 value — required for further measurements.

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File 2: gas_sensor_ppm.ino

• Uses the saved R0 value
• Converts sensor readings into methane concentration (ppm)

Use

• During actual measurements

Output

• Raw ADC value
• Sensor resistance
• Methane concentration in ppm

(All shown in the Serial Monitor)

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How data is saved

• Data appears in the Serial Monitor
• You can:
  • Copy it manually, or
  • Use a serial logging tool
• Save it as .txt files outside Arduino

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Quick summary

• gas_sensor_warming.ino → prepares the sensor
• gas_sensor_ppm.ino → measures methane
• Output = Serial monitor only
• File saving = manual

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