Invent an Interactive Toy with a Raspberry Pi
AbstractDid you ever have a favorite toy like an action figure or doll that could light up, make noise, or move? This project will show you how to make your own interactive toy using the Raspberry Pi Projects Kit. Check out the video to see what this simple, but fun, project looks like. The version you make does not have to be a robot; it can be any shape and have any sound effects you want.
Recommended Project Supplies
A Raspberry Pi (Figure 1) is a tiny computer that you can use to write programs and build and control your own electronic circuits, like the magnet-sensing circuit in this project. The circuit uses sensors to gather information from the world around it. You can use information from those sensors to tell your computer program what to do. Many electronic devices we use every day, like phones and video game controllers, use sensors in the same way.
Figure 1. A Raspberry Pi computer. (Image credit SparkFun Electronics, licensed under Creative Commons Attribution 2.0).
You can do this project just for fun, or turn it into an engineering or science project. To make it an engineering project, you will need to follow the engineering design process. Start by defining what you want your toy to be able to do, then work through the rest of the design process until you have a completed project to show off at your science fair.
If you want to use this for a science project, you will need to follow the scientific method. Start by coming up with a question for which you can use the art project as a tool to help answer. For example, how sensitive is the magnetic sensor? How close does the magnet need to be in order to trigger the lights and sound effects?
- Raspberry Pi Foundation (n.d.). Teach, Learn, and Make with Raspberry Pi - Raspberry Pi. Retrieved August 28, 2019.
- jimblom (n.d.). Reed Switch Hookup Guide. SparkFun Electronics. Retrieved August 28, 2019.
- Science Buddies (n.d.). Raspberry Pi Setup. Retrieved August 28, 2019.
Materials and Equipment
Recommended Project Supplies
This project is written for the Science Buddies Raspberry Pi Projects Kit. There are two kit options available:
- Raspberry Pi Projects Kit (if you do not already own a Raspberry Pi), comes with:
- Raspberry Pi model 3B+
- Micro-USB power cable
- HDMI cable*
- Clear plastic case for Raspberry Pi
- All the circuit components to do all 8 Science Buddies Raspberry Pi projects
- 16GB SD card preloaded with Raspbian and quick link to Science Buddies instructions
- Raspberry Pi Circuit Parts Only Kit (if you already own a model 2B or higher), comes with:
- All the circuit components to do all 8 Science Buddies Raspberry Pi projects
- 16GB SD card preloaded with Raspbian and quick links to Science Buddies instructions
To set up your Raspberry Pi, you will also need the following parts (not included in either kit option):
- TV or computer monitor with HDMI input*
- USB keyboard and mouse
*If you have a TV or monitor with a DVI or VGA input, you will need an adapter. If your monitor does not have built-in speakers, you will need external speakers or headphones. See FAQ for more information.
To do this specific project, you will need the following circuit parts from your kit:
- Male-male jumper wires (3)
- Male-female jumper wires (4)
- LEDs (2)
- Resistors (2)
- Magnetic sensor
You will also need the following materials, not included in your kit:
- Arts and crafts supplies to build your toy (cardboard, fabric, pipe cleaners, googly eyes, glue, etc.)
Playing with toys you buy at the store is fun, but imagine playing with a toy you have designed and made! In this project, you will learn how to design an interactive toy like the robot in the video below. The robot is made with a magnet sensor that can detect when a magnet is nearby. If you have not already, you will need to set up your Raspberry Pi before you can start the project.
Writing Your Program
If you have never written a program in Scratch before, watch this video to learn how:
The program for this project will tell your "puppet" to do one thing when you bring the magnet close to the magnet sensor, and something else when you move the magnet away. Create the following program in Scratch. Read the tips below the screenshot if you need help.
- If you do not see the set gpio __ to ____ blocks, click More blocks then Add an extension to add the Pi GPIO extension.
- To create a variable, click Data then Make a variable. Variables are convenient when you need to use a number multiple times in a program.
- The __ = __ block can be found under Operators. You use this block to check if two numbers are equal to each other.
- The not __ block can be found under Operators. Along with an if block, you can use this block to check if a certain condition is not true.
Building Your Circuit
To build your circuit, you will need to use a breadboard. If you have not used a breadboard before, watch this video before you continue:
Before you build your "toy" for this project, it is a good idea to get a sense of how the circuit works on a breadboard. This video gives a quick demonstration of how the circuit works (without the sound effects):
To build the circuit, you will need jumper wires, LEDs, and resistors.
You will also the magnet sensor:
Connect the parts to your breadboard as shown in Figure 7. Note: The instructions list a red LED, but you can pick any color you want.
|Part||Picture Reference||First Hole||Second Hole|
|Red M-M jumper wire||J5 |
(Pi Wedge G22)
|Black M-M jumper wire||A17 |
(Pi Wedge GND)
|Magnet sensor||A7||Ground bus|
Your circuit should now look like this (you can add more LEDs later):
Testing Your Circuit
Now, make sure your program and circuit work. Click the green flag to run your program, and then hold the magnet close to the magnet sensor. The LED should light up, and the sound effect you picked should play once. When you move the magnet away, the LED should turn off, and the other sound effect should play once. If everything works properly, then you are ready to connect the circuit to your puppet.
Connecting Your Puppet
Now you are ready to connect your circuit to your "puppet." In addition to connecting the LEDs, you also need to connect the magnet and magnet sensor so they will be close enough to each other. This video shows you how everything is connected inside the robot from the demonstration video:
Take some time to plan out how you want to connect everything to your puppet. Be creative with what action you want to use to activate the magnet sensor. For example, you could design a hat with a magnet inside, and put the magnet sensor inside the top of the puppet's head. Or, you could put the magnet in the puppet's hand, and the magnet sensor somewhere in the puppet's body, so it activates when you bend the arm.
Make sure you securely attach the magnet, magnet sensor, and LEDs to your puppet using tape or glue (tape might be easier to remove if you want to re-use the parts for a different project later). Also make sure you still have access to the leads of the LEDs and magnet sensor, so you can connect the female ends of jumper wires to them. Use the male-female (M-F) jumper wires to connect the components to the same holes where they were originally placed on the breadboard. Refer to the Create Light Up Artwork with a Raspberry Pi project if you need help figuring out how to use the M-F jumper wires.
Your program already has the code to light a second LED, connected to pin G23 on the Pi Wedge. Can you figure out how to connect this LED to your circuit? Look at the troubleshooting tip below if you need help.
Testing Your Puppet
Once you have everything assembled, click the green flag to run your program. Adjust your puppet to bring the magnet close to the magnet sensor, then move it away. Do the LEDs turn on and off, and the sound effects play properly? If so, congratulations, you have created your own interactive toy! If something does not work, see the troubleshooting tips below.
There are plenty of possibilities for how you can modify or improve your puppet. Here are just a few ideas:
- Your kit contains two magnets and two magnet sensors. Add a second magnet and sensor to make the puppet respond to two unique actions.
- Add more LEDs to your puppet. Make the LEDs flash or blink in a certain pattern instead of just staying on or staying off. See the Build an Electronic Piano with a Raspberry Pi project for instructions on adding more LEDs.
- Make your puppet respond to motion. See the Make a Motion Sensor Alarm with a Raspberry Pi project for instructions on using the motion sensor.
- Make your puppet react to light and darkness. See the Create Light Up Artwork with a Raspberry Pi project for instructions on using the light sensor.
For troubleshooting tips, please read our FAQ: Invent an Interactive Toy with a Raspberry Pi.
Ask an Expert
Frequently Asked Questions (FAQ)
Kit General Questions
- Who is the kit appropriate for?
- Are the kit parts reusable?
- Aren't there other Raspberry Pi kits on the market? How is yours different?
- I already have a Raspberry Pi. Can I just buy the circuit parts separately?
- What programming language do the projects use?
Setting Up and Using Your Raspberry Pi FAQ
- How do I connect my Raspberry Pi to my TV or computer monitor?
- Can I use a laptop as a display and/or keyboard?
- How do I connect my Raspberry Pi to the internet?
- How do I shut down or reboot my Raspberry Pi? There's no power button!
- How can I adjust the Raspberry Pi's display resolution?
- I have everything connected properly, why can't I hear any sound?
- Why won't my Raspberry Pi turn on?
- My Raspberry Pi starts to boot up, but then it freezes or the screen goes blank. What is wrong?
- My Raspberry Pi froze and is not responding to mouse or keyboard input. What should I do?
- My Raspberry Pi is acting strangely (it suddenly will not boot up properly, certain programs do not work, etcetera). What is wrong?
- I think I corrupted my Raspberry Pi's SD card. What should I do?
- I need help with a question, related to my Science Buddies Raspberry Pi Projects Kit or Raspberry Pi Circuits Parts Only Kit, not listed here. Who can I ask?
Kit General AnswersQ: Who is the kit appropriate for?
A: The kit is meant for anyone (ages 8 and up) who wants to learn some basic programming and electronics skills while having fun. Students up to age 10, or older if their reading skills are behind grade level, may need adult assistance in reading and following the on-screen instructions. The projects included in the kit were beta tested and approved by students ages 8 to 16.
Q: Are the kit parts reusable?
A: Yes, all the electronics components in the kit can be re-used to do new projects or to repeat the projects.
Q: Aren't there other Raspberry Pi kits on the market? How is yours different?
A: Yes, there are other Raspberry Pi kits, and some of them are quite good! The Raspberry Pi Projects Kit and Raspberry Pi Circuit Parts Only Kit have been designed to contain the specific materials needed to do the accompanying Science Buddies Raspberry Pi projects. Our kit and associated projects are specifically meant for people who have no prior experience programming or connecting circuits. The projects are 100% beginner friendly with clear on-screen instructions, pictures, and videos. We think the kit, with its associated projects, is one of the most fun kits out there! But, if you are already an ace programmer or electronics guru, you may not find this the best fit for your own personal use. Even so, it may be a fun way for you to introduce others to programming and electronics.
Q: I already have a Raspberry Pi. Can I just buy the circuit parts separately?
A: Yes! We sell two different kits: the Raspberry Pi Projects Kit which includes a Raspberry Pi and the required accessories, and the Raspberry Pi Circuit Parts Only Kit, which only contains the additional circuit parts you need to do the Science Buddies projects. Both kits contain an SD card with the Raspbian operating system and a desktop shortcut to the Science Buddies project instructions.
Q: What programming language do the projects use?
A: The projects use Scratch 2. Scratch is a "graphical" programming language developed by the MIT Media Lab. It allows you to write code by clicking, dragging, and snapping together color-coded blocks. This allows beginners to write working code without worrying about formatting or typos. On the Raspberry Pi, Scratch allows you to control the general purpose input and output (GPIO) pins so your program can interact with a circuit in the physical world.
Note: three different versions of Scratch (1, 2, and 3) are available for the Raspberry Pi. The instructions for the Science Buddies projects (including example code) are specifically written for Scratch 2, which runs well on the Raspberry Pi model 3B+. If you have an older model Raspberry Pi, Scratch 2 may run more slowly, or may not run at all. If you want to use a different version of Scratch, you will need to consult the official documentation for Scratch 1.4 or Scratch 3 and modify the programming steps accordingly.
Setting Up and Using Your Raspberry Pi FAQ AnswersQ: How do I connect my Raspberry Pi to my TV or computer monitor?
A: The easiest way to set up your Raspberry Pi is to use an HDMI cable (included in the Science Buddies Raspberry Pi Projects Kit) to connect to a TV or computer monitor that has built-in speakers. If you are using a computer monitor with an HDMI port but no built-in speakers, you will also need separate speakers or headphones with a 3.5 mm audio plug (a regular "headphone jack").
If your TV or monitor does not have an HDMI port, you will need an HDMI to DVI or HDMI to VGA adapter (see pictures in table below). DVI and VGA do not transmit sound, so you will need separate headphones or speakers if you are using one of those options.
Q: Can I use a laptop as a display and/or keyboard?
A: The short answer is "not easily." Many newer laptops have HDMI ports, but they only function as HDMI out, to send a video signal from the laptop to a television or projector. They do not work as HDMI in to display an external signal on the laptop's screen. The laptop's keyboard is only designed to work with the laptop itself, not as a standalone keyboard for an external device like the Raspberry Pi.
The longer answer is that, similar to the Remote Desktop feature on Windows and Mac computers, you can use special software to remotely operate a Raspberry Pi that is connected to the internet. This would allow you to control a Raspberry Pi using your laptop's screen and keyboard. This option is only recommended for advanced users, and you can find instructions at Raspberry Pi Documentation.
Q: How do I connect my Raspberry Pi to the internet?
A: Unlike earlier models, the Raspberry Pi 3B+ contains built-in Wi-Fi functionality. It does not require an external USB Wi-Fi adapter. You can connect your Raspberry Pi to the internet by clicking the internet icon in the taskbar and searching for available Wi-Fi networks, just like you would on a Windows or Mac computer. Your Raspberry Pi also has an ethernet port, which you can use to plug directly into a router for a hardwired connection.
Q: How do I shut down or reboot my Raspberry Pi? There's no power button!
A: Unlike most computers, the Raspberry Pi does not have a power button. You can shut down or reboot by clicking the raspberry icon in the upper left corner of your desktop, then select Shutdown. After the Raspberry Pi has shut down, it is safe to unplug the micro-USB power cable. Plug the cable back in to reboot. Important: never unplug the power cable while the Raspberry Pi is still running. This can corrupt the SD card.
Q: How can I adjust the Raspberry Pi's display resolution?
A: Click the Raspberry Pi logo in the top-left corner of your desktop. Select Preferences, then Raspberry Pi Configuration, then click the Set Resolution... button on the System tab.
Q: I have everything connected properly. Why can't I hear any sound?
A: Right-click the speaker icon on the desktop taskbar. This allows you to manually select HDMI or analog (the headphone jack) for sound output. Make sure you have the proper output selected. Also, make sure your Scratch program is set to play a sound. You can write a simple program to test if your sound is working using the "when space key pressed" and "play sound meow" blocks.
Q: Why won't my Raspberry Pi turn on?
A: If your Raspberry Pi will not turn on (the screen remains blank after everything is plugged in), go through this checklist to make sure everything is set up properly.
- Make sure your SD card is pushed in all the way (see Figure 1).
- Make sure the red power LED on your Raspberry Pi (labeled "PWR," near the micro-USB port, see Figure 2) is on. This means the Raspberry Pi is receiving power from the micro-USB port. If the LED is not on, make sure you pushed the micro-USB connector into the micro-USB port all the way.
- When you first plug the micro-USB cable in, the green LED (labeled "ACT," next to the PWR LED, see Figure 2) should flash several times. This LED flashes when the Raspberry Pi reads data from the SD card. After the Raspberry Pi is done booting up, it should turn off. If it does not flash at all, your SD card might not be inserted properly. Go back to step 1.
- Make sure your display (television or monitor) is turned on. If your display is turned off, you will not see anything on the screen, even if the Raspberry Pi is on.
- Make sure your display is set to the correct input. Many modern TVs have more than one HDMI input, and some computer monitors have DVI or VGA inputs in addition to HDMI.
Figure 1. A micro-SD card that is inserted properly (left) and one that is not pushed in all the way (right).
Figure 2. The PWR (red) and ACT (green) LEDs near the micro-USB port.
Q: My Raspberry Pi starts to boot up, but then it freezes or the screen goes blank. What is wrong?
A There may be a problem with your Raspberry Pi or SD card. If you are using the Raspberry Pi or SD card that came with the Raspberry Pi Projects Kit or Raspberry Pi Circuit Parts Only Kit purchased from our partner Home Science Tools, please contact them directly at email@example.com for assistance.
Q: My Raspberry Pi froze and is not responding to mouse or keyboard input. What should I do?
A: First, be patient and give the Raspberry Pi a few minutes to try and process whatever it was doing. If you click on a whole bunch of things in rapid succession, or run a really complicated Scratch program, the Raspberry Pi might slow down or freeze temporarily.
Next, if you are using a wireless keyboard and mouse, make sure they have fresh batteries.
Finally, as a last resort, if your Raspberry Pi is not responding, unplug the micro-USB cable and plug it back in. In general, you want to avoid doing this, because suddenly cutting power to the Raspberry Pi without properly shutting it down first can corrupt the SD card, and prevent the Raspberry Pi from working properly.
Q: My Raspberry Pi is acting strangely (e.g. it suddenly will not boot up properly, certain programs do not work, etc.). What is wrong?
A: If your Raspberry Pi is not "dead," but seems to be behaving strangely, there is a chance that your SD card has become corrupted. This can happen if you unplug the Raspberry Pi's power cord without properly shutting it down first. See the next question.
Q: I think I corrupted my Raspberry Pi's SD card. What should I do?
A: If the SD card came with the Raspberry Pi Projects Kit or Raspberry Pi Circuit Parts Only Kit you purchased from our partner Home Science Tools, please contact them directly at firstname.lastname@example.org for assistance. Make sure to include a detailed description of the problem you are having. They will work with you to resolve the issue.
If you like this project, you might enjoy exploring these related careers:
Contact UsIf you have purchased a kit for this project from Science Buddies, we are pleased to answer any question not addressed by the FAQ above.
In your email, please follow these instructions:
- What is your Science Buddies kit order number?
- Please describe how you need help as thoroughly as possible:
Good Question I'm trying to do Experimental Procedure step #5, "Scrape the insulation from the wire. . ." How do I know when I've scraped enough?
Good Question I'm at Experimental Procedure step #7, "Move the magnet back and forth . . ." and the LED is not lighting up.
Bad Question I don't understand the instructions. Help!
Good Question I am purchasing my materials. Can I substitute a 1N34 diode for the 1N25 diode called for in the material list?
Bad Question Can I use a different part?
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