pxt-calliope/olddocs/lessons/digi-yoyo.md

# digi yoyo lesson

Create a counter with a while loop.

## Topic

While Loop

## Quick Links

* [activity](/lessons/digi-yoyo/activity)
* [challenges](/lessons/digi-yoyo/challenges)
* [quiz](/lessons/digi-yoyo/quiz)
* [quiz answers](/lessons/digi-yoyo/quiz-answers)

## Prior learning/place of lesson in scheme of work

Learn how to creating a **while loop**, `while condition do` to repeat code while a condition is true. We will be learning how to create a digi yoyo app using a while loop, a variable, as well as basic commands, such as pause and show number.

## Documentation

```cards
let x = 0
basic.showNumber(0)
while (true) {}
basic.pause(20)
```

## Objectives

* learn how to create a local variables to store data and use it in your code
* learn how to set or change the value of a local variable
* learn how to repeat code while a condition is true
* learn how a relational comparison (<) of numbers will yield a Boolean
* learn how to pause your code for the specified number of milliseconds
* learn how to show a number on the LED screen