Trash Chomper

Build a garbage eating monster!

Session ROLES:

🐙 = Site Coordinator

🦉= Mentor


A Note for Site Coordinators and Mentors

This session guide provides a detailed outline for the Trash Chomper activity, but feel free to improvise or put your own spin to things. If you have an idea for a challenge or prompt that will get girls excited, go for it! If something is not working well, change course and experiment another path forward. 

If you do change things up, we would love to hear what has been successful for you!  

Get Social!

📷 We love to see invention in action! Take photos/videos of your session and tag us on social with the hashtag #snapthegap. *Please make sure you have sharing authorization from parents and your affiliated organization before posting.


Session Overview

Girls will use the littleBits Invention Cycle, and an understanding of the basics of circuitry, sensors, and and motion, to construct an automatic Trash Chomper. Girls will then improve upon or modify the functionality of their Trash Chompers to create an invention for the house of the future. Conclude the activity by having girls act out a future scenario on which their invention will be used.


Session Details




2 hours





Prerequisite Knowledge:

Intro to littleBits

Invention Cycle



Bits + Accessories:

Snap the Gap STEM Kit


Mentors will need to bring a connected device (phone, tablet, or computer) to access instructional videos

Other Materials:

Extra 9V batteries


Nice to Have:

Colored Paper





Theme: Smart Objects

Objectives: By the end of the session, girls will be able to:

  • Create and test a circuit containing a power source, inputs and outputs

  • Construct a prototype of a trash chomping robot using littleBits

  • Test their prototypes and make improvements 

  • Demonstrate their ability to Create, Play, Remix and Share an invention through the littleBits Invention Cycle

  • Summarize their process and Share the resulting invention by acting out skits with their prototype in use


Set Up


  • Make sure all the supplies for this session are prepped and ready to go.

  • We suggest handing out the kits during the CREATE phase, after the introduction.


  • Make sure to bring a charged connected device (phone, iPad, or computer) to access instructional videos during the session.


Meet Up

5 min


Take attendance and make sure mentors and girls are paired off.


Check in with your mentee to make sure she signed up with (previously

Take turns asking each other questions. Example prompts:

  • DIY: Discuss what your mentee explored on since last session. What topics did they find interesting and why? Did they participate in any challenges. If possible, take a look together on

  • What's one thing you created or invented this week?



10 min


Today you’ll be using your expertise to design an invention for the home of the future. We will start out by making a trash chomping monster that turns cleaning up into a game. When you are building the Trash Chomper today, think about other objects in your home that you could supercharge with Bits. Ex: a chair, a mailbox, or a piggy bank!

Discuss: You spend a lot of time in your home. How could you make it even better? Think of something that could be made easier, more exciting, or that you wish existed. Have girls share ideas aloud with the group.

Before jumping into the challenge, provide a quick review of the Invention Cycle framework. Ask girls to share lessons learned about Bits, the invention process and things they enjoyed or struggled with from previous challenges.



5 min

🦉MENTORS Review session inspiration videoS and prompts with girls 

Turn boring objects like trashcans into smart objects. These trashcans are interactive and help the environment by making it fun to pick up litter and recycle.


A trash can that makes a sound when you throw something away keeps people from littering

A smart recycling bin that turns recycling into a game

littleBits Powered Recycling Bin


Discuss/Careers: Electrical Engineers, Product Designers


40 min


Facilitate the CREATE, PLAY, & REMIX activities with mentees.


During the CREATE, PLAY, & REMIX activities, float around the room and observe/help out where needed. You will also monitor the time and announce when the group should come together to share.

The Trash Chomper

Build a garbage eating monster.


CREATE: Watch following video playlist for build instructions:

  1. Robots

  2. Create Trash Chomper



10 min

PLAY: Try out your invention! 

  • Once the prototypes have been constructed, girls should test their inventions to make sure they work and to see what they can learn about them. Keep in mind that the inventions likely won’t work perfectly the first time; failure is part of the process.

  • In small groups, ask girls to discuss/explain how the circuit works, including the mechanical arm. A clear understanding of how it works will help them explore and experiment during the Remix phase.  



20 Min

Now it’s time for girls to put their Engineering Design skills to work to improve or modify their Trash Chomper. How can you use Bits and craft materials to improve or customize your invention? If there is time, try out more than one remix idea! Here are some ideas:

  • Try using your Trash Chomper in different places/scenarios. 

    • Can it be used for something other than trash?  Can it be a secret compartment? A piggy bank? A pet food dispenser? What other ideas do you have?

    • What happens if you turn it upside down or on its side? Does that change the functionality?

nav 3.png
trash 3.png
  • Experiment with Bits

    • Try swapping the Sound Sensor Bit in place of the Proximity Sensor Bit. How does this change the function of your Trash Chomper? Hint: Try clapping to make it chomp.

    • Try adding other Bits. What happens if you add a Long LED Bit or a Buzzer Bit? How could this improve your invention? 

trash 2.png
  • Add Materials

    • How can materials transform your Trash Chomper into something else like a mailbox or a pet feeder? Use stickers or add other craft materials and get creative here.

    • Give your invention some personality - does it look like an animal? A plant?

    • Add a sign or message

Pair up girls so they each have someone else to test out their prototype. Test the invention after a few improvements have been made. Have girls ask the person what their favorite features are and what suggestions they have to make it better.

Ask girls to explain their remix choices and the resulting change in functionality and outcomes.



15 Min


  • Gather girls together to share their remixed inventions

  • Girls may want to give their invention a name and act out a short skit of a scenario in which their product can be used. Sharing and receiving feedback on the invention is a great way to fuel another round of remixing, playing and sharing.

  • Snap photos of the final invention!

Give girls a preview of the next session:

  • Next week, we will learn about inventions that help people and build a robotic arm.



5 Min


Reflect with your mentee: “What is one new thing that you learned during this challenge?”



10 Min

Wrap Up


  • Make sure girls power off the Power Bit and disconnect the battery.

  • Deconstruct inventions: Make sure to take pictures of what girls have made. Girls may take home the paper portion of their invention if they like.

  • Clean up: Make sure girls have all the parts shown on the side of the box and put them away in the kit.


  • Announce Super Important Homework: Before next session, girls should go on, select a topic that sounds interesting, participate in 1 challenge, and upload to the community. You will discuss it next time!

  • Store kits away for next time 


Log Your Session

Tell Us How It Went

Your feedback is essential to help us improve the program!



After the session, please fill out the Session Feedback Form

Get Social! 

📷 We love to see invention in action! Take photos/videos of your session and tag us on social with the hashtag #snapthegap. *Please make sure you have sharing authorization from parents and your affiliated organization before posting.