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MLX90614 Body Temperature
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MLX90614 Body Temperature

by castellana on Tue May 12, 2020 5:00 am

Hello
I have an MLX90614 and I use it to detect the correct temperature of things, and it works. But of course if I detect the body temperature not working properly, it measures 33 34 32 degrees Celsius. Surely there is some calculation I have to do or some document to read. How do I estimate or calculate body temperature using MLX90614? Can anyone give me suggestions?

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Re: MLX90614 Body Temperature

by adafruit_support_bill on Tue May 12, 2020 6:01 am

There are a couple of things to consider when measuring with a sensor like the MLX90614.

The first is the field of view. The MLX90614 has a 90 degree field of view. The temperature measurement will be the average over the full field of view. The chart on page 35 of the data sheet shows the sensitivity relative to the angle of incidence.
https://cdn-shop.adafruit.com/datasheets/MLX90614.pdf

The other factor to consider is the emissivity of the target. The efficiency with which a surface is capable of emitting radiant energy is called 'emissivity'. The MLX90614 is calibrated for an object emissivity of 1. Human skin is typically in the range of 0.98. So readings should be adjusted accordingly.

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Re: MLX90614 Body Temperature

by spiralbrain on Tue Jun 02, 2020 4:53 am

I tried changing the emissivity using the mlx.writeEmissivity but for some reason it cannot write a value beyond 0.5
Has anyone tried changing emissivity using Adafruit Library?

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Re: MLX90614 Body Temperature

by spiralbrain on Tue Jun 02, 2020 9:01 am

I reverted it back to 1.0 using mlx.writeEmissivityReg(65535); just in case someone reads this thread looking for a solution.

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