---
title: "Activity: Puppy Bot"
date: "2021-06-03"
categories: ["Activities"]
tags: ["Branching", "Iteration", "Functions", "Motors", "Ultrasonic", "Intermediate"]
codingSkills: ["Branching", "Iteration", "Functions"]
roverConcepts: ["Ultrasonic", "Motors"]
excerpt: "Branching and looping with the ultrasonic sensor."
featuredImage: "/images/resources/puppy-bot.png"
---


Program the rover to act like a puppy. When the rover detects an object within 50cm using the ultrasonic sensor have the rover charge forward. Once the rover gets within 20cm from the object it stops and waits for it to move. When the puppy bot can’t see anything with the ultrasonic, slowly spin on the spot looking for something to follow.

### Activity Demonstration

<iframe width="560" height="315" src="https://www.youtube.com/embed/E4Bi3NhsmJI" title="Puppy Bot Activity Demonstration" frameBorder="0" allow="accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture" allowFullScreen></iframe>

### Setup

The distances used in the code can change depending on how much space you have. Just keep in mind the max range of the ultrasonic sensor is about 100cm. If the ultrasonic sensor can’t detect anything it will return a reading of 255cm. The below solution can be extended to use functions in each branch to make the rover better at finding and following people.

### Here’s Our Approach

#### **Stage 1**

Start with setting up our IF statement with 3 branches. Firstly if the rover detects something within 20cm with the Ultrasonic sensor, stop the rover. Then use an ELSE IF (ELIF) that checks if the rover detects something within 50cm. Lastly we have the ELSE branch for when the ultrasonic sensor doesn’t detect anything close.

#### **Stage 2**

Place the appropriate motor blocks for the conditions. When the rover is stationary waiting for it’s owner to move, stop all motors. When the rover is starting to chase move forward at high speed. When it senses nothing from the ultrasonic just slowly turn on the spot searching.

#### **Stage 3**

We want to repeat this behaviour forever so place everything inside a repeat while true loop.

![](/images/content/813845-screenshot-2023-10-31-083156.png)

Example Code
