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Topic: MLX90614 distance (Read 7965 times) previous topic - next topic


I'm a newbie, i try an arduino UNO rev.3 with MLX90614, with this code example http://interface.khm.de/index.php/lab/experiments/infrared-thermometer-mlx90614/.
Everything works, I read the temperature on serial monitor, but when I move the object to more than 3 cm, the reading is not real.
It's possible increase the reading distance? I do not need to read the temperature from a small object, but from a surface.



http://www.melexis.com/Assets/IR-sensor-thermometer-MLX90614-Datasheet-5152.aspx -> download the data sheet
pages 33 to 36 has some information about the field of "vision" of the sensor. 
Page 40 has some information that looks relevant to your question.
page 43 - 44 has some information that looks relevant to your question.


Another thread here: http://arduino.cc/forum/index.php/topic,86419.msg647420.html#msg647420

I was having same problems.

The only law for me; Ohms Law: U=R*I       P=U*I
Note to self: "Damn! Why don't you just fix it!!!"


You have to realize how these sensors work - they are detecting the total energy in the infra-red radiation from object over a wide angle - so have to either be close to the object so it fills the field of view, or you need a lens/mirror (that works in the right part of the infra-red spectrum) to fill its field of view with infra-red from the object in question.

Another possibility is to use a mirror tube between sensor and object to steer the light - but like all the optical means you will have to compensate for the loss of infra-red in the optical path (for instance I think only exotic materials are suitable for lenses, and not all mirror materials that work at optical wavelengths will work well at infra-red wavelengths).
[ I will NOT respond to personal messages, I WILL delete them, use the forum please ]

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