Lab 2: Take your temperature

Introduction

In the previous lab, we measured the resistance of a single, non-changing resistor. In this lab, we'll measure the resistance of a material with a temperature dependant resistivity. This circuit element is called a thermistor. We will also add a new variable to monitor: time.

Goals

Instructions:

  1. Construct a simple voltage divider circuit and use the thermistor to measure the temperature change caused by a phenomenon of your choice.
  2. Adapt the example sketch: AnalogReadSerial, as needed, to measure the voltage and time.
  3. Record the values (using a reasonable Δt - i.e. if you're measuring a whole day of values, 1 minute intervals might be appropriate)
  4. Copy the data from the serial monitor into a text editor and save as a csv file.
  5. You might need to clean up the csv a bit to remove any funky data in the beginning or end.
  6. Plot the temperature* as a function of time.
  7. Describe your measurement in words and if there is any math/physics that would help, please share.

* When I write 'temperature' here, I mean the temperature! The main challenge of this lab is to adapt your plotting code to convert the voltage measurement to a calibrated temperature.

Coding tips

To format your output in a way that can be easily read, you can combine three Serial.print() commands: 


Serial.print(millis());
Serial.print(',');
Serial.println(sensorValue);
(The last command, println(), indicates that this is last part of the line, and the next output will be on a new line.)

Measurement

Use the Arduino to measure the resistance of your thermistor.

Example set up for thermistor.

Analysis

Use your understanding of the voltage divider circuit and the documentation for your thermistor to turn the resistance measurement into a calibrated temperature in Kelvin. This means the vertical axis of your graph should have the units of Kelvin. Convert your time units to something that makes sense for a human to interpret.

You might find the contents of these tutorials useful for this lab:

  • Sharing Code Online
  • Loading In Data
  • Document Making UPDATED

    • Report

    Due: 4 pm, Oct 7, via BlackBoard

    To submit: