Unit 3: Loops and Repetition

Computers are brilliant at doing the same thing over and over — infinitely faster and more reliably than humans. This unit teaches you to harness that power with loops.

Lessons in This Unit

Lesson	Title	Key Concepts
Lesson 8	While Loops	while, counter variables, infinite loops, +=, break preview
Lesson 9	For Loops and range()	for, range(start, stop, step), nested loops, enumerate()
Lesson 10	IR Sensor, break, and continue	IR sensor wiring, break, continue, loop control

New Hardware: IR Proximity Sensor

The IR sensor detects when an object is nearby by emitting infrared light and detecting reflections. Digital output — LOW when object detected.

What You’ll Be Able to Do by the End

• Use while loops for repeated actions and “wait until” patterns
• Use for loops to iterate a fixed number of times or through a list
• Use range() with start, stop, and step arguments
• Use break to exit a loop early and continue to skip an iteration
• Build LED animations and sensor-responsive programs

Loops are one of the most powerful tools in programming. After this unit, you can make your LED display complex animations and your programs respond continuously to sensors.