Thermal Image Sensors

In the current COVID-19 crisis, thermal image sensors are becoming need of the hour. In the last few weeks, I got several companies asking for the development of thermal image sensor based solution for the on-going COVID-19 crisis mainly for screening automation.

Thermal Image Sensors 1

The problem was no one had the idea about how the solution could be realized, if sensors are available, what is accuracy, what kind of development effort will be required, how soon we can develop such solution, what are the limitation, etc.

So, I thought let me put the details together so that it is useful first level information for companies planning to create solutions around thermal image senors.

I hope you will find it interesting.

Thermal Image Sensors

The first question is are there sensors available in the market which could be used, how many thermal image sensors are you aware of which could be used? Let us see all of them one by one.

1. FLIR LEPTON

FLIR is a company specialized in thermal cameras and now with the acquisition of point gray they have also entered the machine vision market with visible light imaging cameras, they have been the thermal image camera solutions company and a few years back they rolled out sensors for professionals so they can start developing custom thermal image sensor based solutions.

As mentioned on their website

The FLIR Lepton® is a radiometric-capable LWIR camera solution that is smaller than a dimefits inside a smartphone, and is one tenth the cost of traditional IR cameras. Using focal plane arrays of either 160×120 or 80×60 active pixels, Lepton easily integrates into native mobile-devices and other electronics as an IR sensor or thermal imager. The radiometric Lepton captures accurate, calibrated, and non-contact temperature data in every pixel of each image.

Resolution, Price Range, Accuracy

They have two family of thermal sensors, one with 80 x 60 pixels and another one which is the latest family, has 160 x 120 pixels.

These thermal image sensors are not cheap, as show below, they costs around 175$ – 199$ per unit. Please be careful about accuracy of these sensors. They are not very accurate.

As mentioned in the technical specification:

  • High gain Mode: Greater of +/- 5° C or 5% (typical)
  • Low Gain Mode: Greater of +/- 10° C or 10% (typical)
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Image Credit: FLIR

FLIR LEPTON TEARDOWN

FLIR LEPTON Breakout Board

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FLIR also provides breakout board for these sensors so one can easily interface with MCU/MPU and evaluate for the potential applications.

FLIR LEPTON Interface with Raspberry Pi

Getting started guide showing step-by-step how to interface LEPTON board with Raspberry Pi is available here. These thermal image sensors could be interfaced with smaller MCUs as well as the Image/Video feed comes over SPI interface.

One can buy FLIR LEPTON therma image sensors from here: https://lepton.flir.com/where-to-buy/

Learn more about FLIR thermal image sensors.

2. SEEK THERMAL

Seek thermal is another company based out of California, USA, they manufacture ready to use cameras as well as USB based OEM thermal image sensor modules.

Picture
Image Credit: Seek Thermal

Resolution, Price range & Accuracy

Seek thermal image sensor modules comes with two different resolutions 200 x 150 & 320 x 240. Accuracy of these sensors module is the greater of ±5°C or 5% between 0°C to 300°C scene temperatures.

Easy Getting Started Development Kit

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Seek thermal has developed an easy to use development kit and it’s available on digikey at 499$.

If you want to know the price information about Seek thermal image sensors you need to contact their sales team as they have not provided pricing online. I think the sensor price in retail should be in the same range as of the FLIR LEPTON I guess.

For more information, please check their products page.

3. MELEXLIS

Melexis manufactures special sensors for various applications and one of them is for thermal measurement like for non-contact thermal imaging, thermometers.

MLX90640 Far Infrared Thermal Sensor - Melexis | Mouser

MLX90640 (Resolution, Accuracy, Interface, Price)

Melexis has 32×24 IR thermal sensor array chip which could be used for low resolution thermal imaging, monitoring. Sensor is very popular and a lot of documentation, examples are available how to use for any application.

Best thing about this sensor is its low cost & accuracy which is +-1 Degree C. It is super easy to use as it has I2C interface, check more details in the datasheet.

MLX90640 is available at 36$ @MOQ 260 from mouser. Lot of development boards are available for the sensor like this on digikey.

Thermal Image Sensors 5

One could buy a small development board from sparkfun electronics.

Watch this introduction video

4. Panasonic GRID-EYE Thermal Sensor

AMG8833 is another very popular thermal IR sensor with a resolution of 8×8 pixels and could be interfaced over I2C. Accuracy of this sensor is around +-2.5%

Grid-EYE Infrared Array Sensors - Panasonic | Mouser

It available at just $17 at mouser at MOQ 200.

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One could buy a small development board from sparkfun electronics.

5. HEIMANN SENSOR

Imaging IR Sensors - Thermopile Arrays - Boston Electronics

They have many sensor arrays available from 8×8 to 80×64 pixels resolution. The interface is I2C and it’s quite easy to use.

Price information is available here and ranges from 19$ for 8×8 Sensor to 125$ for 80×64 Sensor at MOQ200.

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They also provide a PC software for easy evaluation, screen shot show above. More information could be found on the product page.

6. OMRON Electronics

They have 4 x 4 pixel MEMs based IR thermal scanner which are mainly used in human presence detection but could be used for other applications where 4×4 pixel resolution is enough. Interface is again I2C here so it is fairly easy to connect with any MCU or MPU.

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The accuracy of the sensor is +-1.5 Degree C for a sensing range of 0°C ~ 50°C and these are available on the Digikey in a module for about 38.5$ at MOQ 100.

I hope you have found the information about thermal image sensors useful.

You can read my other blogs or interesting embedded system articles here where I share some of the practical tips for embedded system design.


I help embedded engineers and start ups build reliable and successful embedded products and providing professional services as embedded system design consultant. If you need any help please let me know here.

Happy Learning to you!

2 comments

    1. You need to check but we can buy online from their website or some other distributors. Don’t hesitate to find yourself and add comments about your findings to help other engineers.

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