Interface NTC thermistor with microprocessor

In summary, the conversation discusses the use of a microcontroller for temperature limit control, using an NTC temperature sensor and a comparator op-amp. The goal is to interface the sensor with the microcontroller without a direct electrical connection. The solution proposed is to use an optocoupler, specifically a LED and a photodiode, to transfer the signal from the comparator to the microprocessor. The individual is seeking assistance with drawing the components correctly.
  • #1
ilovescience85
25
0

Homework Statement


A microcontroller for temperature limit control has a 0 V to 5 V
power supply. An NTC temperature sensor provides an input voltage
to a ・} 5 V comparator op-amp. Depending upon whether the
temperature is below or above the set limit, the output from the opamp
comparator will be low or high. It is undesirable for a direct
electrical connection to exist between the sensor and the controller.
Draw a circuit diagram to show how you could interface the NTC
sensor to the microcontroller. Resistor values are not required.

Homework Equations


N/A

The Attempt at a Solution


I have a diagram of a window comparator circuit (see attached) with the thermistors output being one of the opamp inputs. I think I could use a optics to transfer the signal from the comparator to the microprocessor. I was thinking of a LED to transmit the signal and a photodiode to receive it at the microprocessor, but I'm unsure how to draw this. Any help would be greatly appreciated.
Window Comparator.gif
 
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  • #2
Do a web search on "optocouplers". You may get some ideas.
 
  • #3
Yeah thanks I got some help from my buddy, just wanted to make sure I was drawing the components correctly. Never been great with electrical circuits.
Thanks for the reply.
 

1. What is an NTC thermistor?

An NTC (Negative Temperature Coefficient) thermistor is a type of temperature sensor that changes its resistance in response to changes in temperature. As the temperature increases, the resistance of the thermistor decreases, and vice versa.

2. How does a thermistor interface with a microprocessor?

A thermistor can be connected to a microprocessor using an analog-to-digital converter (ADC). The ADC converts the varying resistance of the thermistor into a corresponding digital value, which can then be read and processed by the microprocessor.

3. What are the advantages of using an NTC thermistor with a microprocessor?

One advantage is the high sensitivity of NTC thermistors, making them ideal for precise temperature measurements. They are also relatively inexpensive and easy to interface with microprocessors, making them a cost-effective solution for temperature sensing.

4. How accurate are NTC thermistors when interfaced with a microprocessor?

The accuracy of NTC thermistors depends on various factors such as the quality of the thermistor, the accuracy of the ADC, and the calibration of the system. However, with proper calibration and circuit design, NTC thermistors can achieve accuracies of up to 0.1°C.

5. Can NTC thermistors be used in harsh environments?

Yes, NTC thermistors are designed to withstand a wide range of temperatures and can be used in both indoor and outdoor environments. They are also resistant to shock and vibration, making them suitable for use in industrial and automotive applications.

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