Displaying sensor data on screen in Arduino - Time & Space Complexity

Time Complexity: Displaying sensor data on screen

O(n)

Understanding Time Complexity

When we show sensor data on a screen, the program runs steps repeatedly to update the display.

We want to know how the time it takes grows as we update more data points.

Scenario Under Consideration

Analyze the time complexity of the following code snippet.

void loop() {
  int sensorValue = analogRead(A0);
  display.clear();
  display.print(sensorValue);
  display.update();
  delay(1000);
}
    

This code reads a sensor value, clears the screen, prints the value, updates the display, and waits one second.

Identify Repeating Operations

Identify the loops, recursion, array traversals that repeat.

• Primary operation: The loop() function runs forever, repeating the steps inside.
• How many times: It repeats once every second, continuously.

How Execution Grows With Input

Each loop reads one sensor value and updates the screen once.

Input Size (n)	Approx. Operations
10	10 sensor reads and screen updates
100	100 sensor reads and screen updates
1000	1000 sensor reads and screen updates

Pattern observation: The number of operations grows directly with how many times the loop runs.

Final Time Complexity

Time Complexity: O(n)

This means the time to run grows in a straight line as we do more sensor reads and screen updates.

Common Mistake

[X] Wrong: "Clearing and updating the display takes constant time no matter how much data we show."

[OK] Correct: If the display shows more data or is more complex, clearing and updating can take longer, so time may grow with data size.

Interview Connect

Understanding how repeated sensor reads and screen updates affect time helps you write efficient embedded programs.

Self-Check

"What if we read and display multiple sensor values each loop instead of one? How would the time complexity change?"