Not sure I choose the right place to ask the question, but... Can I use infrared temperature sensor (such as TS118-3) to measure water surface temperature? I'm afraid some effects as reflection of infrared waves from water surface and blinking because of the water ripple will make its impossible.


1 Answer 1


Yes, you can measure the water temperature with a non-contact sensor. With some care.

The emissivity of water is about 0.98, which is perfect for these sensors. Reflections from the background will not confuse the sensor. The same applies to glass, it's also just a blackbody at thermal IR wavelengths. Any metal surface has low emissivity and will reflect the background, rather than showing its own temperature.

You must still take care of air currents. Particularly if the water is close to boiling, you will have some challenges keeping the steam away from the sensor, while not blowing air over the sensor. Also, you must consider the fraction of the cone of sensitivity that the water covers. The sensor you mention has no lens, so it's probably sensitive over more than a 90 degree angle. You probably need to do some calibration to take into account the cold surroundings of the water.

Finally, consider using an all-in-one device like the Texas Instruments TMP006, which does all the hard analogue stuff for you, and presents itself as an I2C device.


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