Infrared phototransistor to infrared thermometer

In summary: 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. The change in energy is converted to an electrical signal that is displayed in units of temperature after being compensated for ambient temperature variation.
  • #1
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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  • #2
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?
 
  • #3
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.
 
  • #4
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?
 
  • #5
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.
 
  • #6
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?
 
  • #7
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...
 
  • #8
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:
 

1. What is an infrared phototransistor?

An infrared phototransistor is a type of semiconductor device that converts infrared light into electrical signals. It consists of a base, collector, and emitter, and operates by amplifying the current between the collector and emitter when infrared light is detected.

2. How does an infrared phototransistor work in an infrared thermometer?

In an infrared thermometer, the infrared phototransistor detects the infrared radiation emitted by the object being measured. The amount of infrared light detected is converted into an electrical signal, which is then used to calculate the temperature of the object.

3. What are the advantages of using an infrared phototransistor in an infrared thermometer?

One of the main advantages of using an infrared phototransistor in an infrared thermometer is its sensitivity to infrared light. This allows for accurate temperature measurements without the need for direct contact with the object. In addition, infrared phototransistors are compact and relatively inexpensive compared to other temperature sensing technologies.

4. Are there any limitations to using an infrared phototransistor in an infrared thermometer?

Yes, one limitation of using an infrared phototransistor in an infrared thermometer is its sensitivity to ambient temperature changes. This can affect the accuracy of the temperature readings if the thermometer is not properly calibrated. Additionally, the angle of detection and the distance from the object being measured can also impact the accuracy of the measurements.

5. Can an infrared phototransistor be used for other applications besides infrared thermometers?

Yes, infrared phototransistors have a wide range of applications including remote controls, burglar alarms, and motion sensors. They are also used in industrial settings for temperature monitoring, gas detection, and flame detection. Infrared phototransistors are also commonly used in medical devices for blood oxygen level monitoring and non-invasive temperature measurements.

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