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IR Thermometer


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When we say infra-red, we mean all the frequencies below what the human eye can see. That is very wide band of infinite frequencies or wavelengths.

The IR receiver or transmitter in a remote control system use very different wavelengths than an IR thermometer.

For this very simple reason, you cannot use either a receiver or a transmitter for this.

IR thermometers that you can buy in shops use a very different kind of sensor, called microbolometer.

If you want a reasonably accurate thermometer to measure say the temperature of a wall, than I can reccomend the Fluke 62


Alternatively, you can use the TPA81 sensor module (requires microcontroller and programming). This is an array of 8 thermopile elements in a row. You can use it to measure temeprature of objects nearby, very low accuracy but it is great if for example you have a robot and you want it to follow a candle flame.


Hope this helps.


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It depends on what you're trying to do.

It's pretty easy to just trigger a comparator when a sensor is exposed to heat or cold.

Here's an example, Th1 is in a parabolic reflector such as that used by a torch (flashlight in the US), Th2 acts as a compensator, the comparator activates the LED when there's a great enough difference in Th1's and Th2's temperature.

Th1 and Th2 need to be as closely matched as possible, use precision thermistors of you can.

The comparator could be replaced by a differential amplifier.

I got the idea from Forrest Mims Sensor Projects, page 42 & 43

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