Low cost DIY IR Thermometer

Low cost DIY IR Thermometer


To design and develop a low cost IR thermometer which can be built out of components readily available at hobby shops, and built within a day without the need of any expensive equipment.

The basics

IR thermometers are used as initial screening devices to check for human body temperature without making contact with the body. Fever is defined by CDC as body temperature of 100.4F/38C or higher (Source). However, the outside body temperature is different from the inside body temperature and is also dependent on the location of measurement. Extreme care must be taken while measuring temperature; a guide for checking temperature can be found here.

Working principle of an IR thermometer can be found here.

The design

As stated above, the objective is to design a low cost IR thermometer which can be built out of components available at a hobby store, and built at home within a day. Below is a simple block diagram of the design. The design makes use use of Arduino Nano, Generic 16×2 display, 9V battery, laser diode, and thermopile sensor (MLX90614). The enclosure is 3D-printed.

Two versions of the PCB have been developed: the first version is 1-layer, which can be easily etched at home. Here is a guide. The second design is a more compact 2-layer PCB, which can be mass produced.















Schematics and PCB designed using KiCAD.

While the current design makes use of the thermopile sensor MLX90614, we are constantly working on making additional designs to support other thermopile sensors.

Please comment below or reach out to one of us if you have any suggestions or recommendations or questions on any aspect of the design or procurement.

We are also facing extreme shortage of thermopile sensors. If you know of any alternative sensors available within India, please reach out to us.


  1. BOM: https://docs.google.com/spreadsheets/d/1PwoOSnrokXqJqVzkK6yj5rvuNrtC6aV5uEVb-jY0tXU/edit#gid=1261738291
  2. Design files (schematics, Gerber files, enclosure CAD, etc.): https://drive.google.com/drive/folders/1a55Arj23pD1N4WzjrUQBMDq9hy1Yo-RW
  3. Firmware: https://github.com/CaringIndians/thermalsensor


Comments (1)

Aren’t high quality IR Thermometers easily available?
Why re-invent the wheel?

These are easy to procure, if not available in a location around you.

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