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M-Logger, the Thermal Environment Measurement System

This is the support site for the M-Logger system, developed to measure the building thermal environment. M-Logger system has the following features.

• All specifications and technical documents are freely available on the web (open-source hardware).
• Compact size of 64×40×30 mm.
• Capable of measuring dry-bulb temperature, relative humidity, globe temperature, and low air velocity necessary for evaluating thermal comfort.
• Can calculate and display thermal comfort indices (PMV, PPD, SET*) in real-time.
• Measures illuminance to infer room conditions.
• Runs on two AA batteries (no need for a power outlet).
• Can perform continuous measurements for several weeks on batteries.
• The cost per unit is less than $100.
• Initial setup and data collection can be done wirelessly.
• Compatible with Windows, Mac, and Linux.
• Can also be used with a smartphone (iPhone, Android).

Information for Users

1. How to purchase

Available on Amazon.
https://www.amazon.com/dp/B0C7GJ7KW5

2. How to use from a smartphone

With an iPhone or Android, you can use M-Logger instantly.
Please read Chapter 3 of the document for more information.

3. How to use from a PC

Multiple M-Loggers can be connected to a PC to simultaneously display and save measurements.
Please read Chapter 4 of the document for more information.

Information for Developers

1. Git repository

Since M-Logger is open-source hardware, the following information required for its manufacturing is available on GitHub.

• Board design (EAGLE data)
• BOM (Bill of material)
• Project files for programs to be written to M-Logger's microcontroller (Microchip Studio for AVR)
• 3D model data for manufacturing instrument case (Rhinoceros data)
• Project file for the software to use the M-Logger from a smartphone and PC (Visual Studio data)
2. Related paper

This paper reports on the principle of velocity measurement of the M-Logger, the magnitude of error, and the continuous operation time with batteries.

Others

• Appearnace of the M-Logger





• Example of visualization of measurement results
This is an example where 85 devices were installed in a floor air-conditioning laboratory to measure the thermal environment spatially at 3-second intervals.
The size of the spheres represents velocity, and the color represents dry-bulb temperature.
The visualization effectively shows cold air being blown from the floor and being sucked in through the central ceiling intake.