Temperature Sensor in Python

Hello all, in this blog, we will go through the process of creating a virtual implementation of a temperature sensor using python!

But first, let's understand how temperature sensors work in real life!

How temperature sensors work?

Temperature sensors in real life read a voltage value that represents the current temperature, then this value goes through an ADC (Analog to Digital Converter), which converts the analog signal to a digital one resulting in what we call ADC raw value.

Afterwards, based on the sensor sheet and equations, each ADC raw value get converted to the corresponding temp value that we can read and interpret!

Let's consider the following sensor sheet:

• System voltage: 5 v

• Sensor's Min Volt = 0

• Sensor's Max Volt = 2.442

• Min Temp = - 50 Celsius

• Max Temp = 50 Celsius

And another important information you find in a sensor's sheet, is the ADC resolution.

Let's suppose that our sensor has an ADC of 12-bit resolution, which means, the maximum value measured is 4095 (in our numbering system)

Now, given the above information, we can compute the ADC raw value for a given voltage input!

ADC = input voltage * ( resolution / system voltage )

Alright, now it's time to know how ADC raw values get converted to temperatures.

Consider the following linear graph for different ADC, TEMP points:

What is the equation of this line?

Easy, if you remember from your math classes, the equation of the straight line is:

y = mx + c

let's calculate m (the slope of the line)

m = (y2-y1) / (x2-x1)

Taking any two points on the line, m = 0.05

Great! what about c? c is the y-intercept of the line, which is - 50

Hence, the equation of our straight line is:

y = 0.05x - 50

Note: there is a relation between the points, we can use that relation in building our ADC to TEMP function.

What is it?

When x = 0. y = -50

When x = 1000. y = 0

When x = 2000. y = 50

Look at y values!

Using this clue we can write our function recursively!

Alright, enough theory, let's code.

First, configuration variables:

Analog to Digital Converter:

ADC to TEMP:

A function we can call in the main:

Test our program

Input the min volt:

Input the max volt:

Input 1.1221:

And that's it!

Thanks for reading!

Congrats on building a virtual temperature sensor using python!

You can find the code in my GitHub. Happy Learning!