Infrared phototransistor to infrared thermometer

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SUMMARY

The discussion centers on modifying an infrared phototransistor to measure temperatures between -20°C and 120°C for a tire temperature monitoring system. Participants explain the fundamental principles of infrared thermometers, highlighting that they detect electromagnetic radiation emitted by objects and convert it into an electrical signal to determine temperature. Key components mentioned include differential amplifiers for temperature compensation. The conversation emphasizes the importance of understanding the underlying mechanisms of infrared thermometers before attempting modifications.

PREREQUISITES
  • Understanding of infrared thermometers and their operational principles
  • Knowledge of electromagnetic radiation in the 0.7 to 20 µm range
  • Familiarity with differential amplifiers and their role in temperature compensation
  • Basic electronics and circuit design skills
NEXT STEPS
  • Research the operational principles of infrared thermometers on Wikipedia
  • Study the role of differential amplifiers in temperature measurement
  • Explore the design and functionality of infrared phototransistors
  • Investigate temperature compensation techniques in electronic sensors
USEFUL FOR

Students in electronics or engineering fields, hobbyists designing temperature monitoring systems, and professionals interested in infrared sensing technology.

Moses Freeman
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I am designing a tyre temp monitoring system for my Final year project and I would like to know if it is possible to somehow modify a infrared phototransistor to be able to measure an objects temperature in a range of -20 - 120 C.

Any suggestions would be greatly appreciated.
 
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Moses Freeman said:
I am designing a tyre temp monitoring system for my Final year project and I would like to know if it is possible to somehow modify a infrared phototransistor to be able to measure an objects temperature in a range of -20 - 120 C.

Any suggestions would be greatly appreciated.

Welcome to the PF.

Can you explain a bit about how IR thermometers work?
 
I have a basic knowledge of how they work:

Objects with temperatures above zero kelvin emit electromagnetic radiation in the form of waves, the radiation between 0.7umm and 20umm is collected by the lens of the thermometer which is then focused onto the sensor. The output is an electrical signal which is then worked out to find the temperature.

I am not too sure about the internal circuitry but I believe they use a few differential amplifiers for the temperature compensation.
 
Moses Freeman said:
I have a basic knowledge of how they work:

Objects with temperatures above zero kelvin emit electromagnetic radiation in the form of waves, the radiation between 0.7umm and 20umm is collected by the lens of the thermometer which is then focused onto the sensor. The output is an electrical signal which is then worked out to find the temperature.

I am not too sure about the internal circuitry but I believe they use a few differential amplifiers for the temperature compensation.

As the temperature of the object changes, what changes about the IR light coming off of it that is used to figure out the temperature?
 
I believe the change in energy is converted to an electrical signal that is displayed in units of temperature after being compensated for ambient temperature variation.
 
berkeman said:
As the temperature of the object changes, what changes about the IR light coming off of it that is used to figure out the temperature?

Frequency?
 
Moses Freeman said:
I believe the change in energy is converted to an electrical signal that is displayed in units of temperature after being compensated for ambient temperature variation.

That's not very specific, nor very accurate. What reading and research have you done so far on the subject? This is *your* project after all, so you should be doing the reading to gain a basic understanding of how these things work.

Please do some reading at wikipedia and/or HowStuffWorks, and then tell us in better detail what the mechanism is behind IR thermometers...
 
perplexabot said:
Frequency?

In case you hadn't noticed, I'm trying to get the OP to actually do some work here. Please let him do some research and get back to us. Thanks :smile:
 

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