Stack-chan - JavaScript driven super-kawaii robot

An easy-to-build and companion robot for everyone

Public Chat
Similar projects worth following
Stack-chan is a palm-sized super-kawaii companion robot with M5Stack embedded.
It can shake its head, watch people's faces, talk, and possess you with various face expressions.
The exterior, board data, and software are fully open source. Detailed assembly instructions are available, so anyone can make one.

The open communication robot for everyone

In recent years, a variety of communication robots have appeared on the market. However, most of them are "closed", dependent on specific proprietary services, or their specifications are not disclosed to the public. In fact, compared to other bipedal, quadrupedal, and wheeled robots, there are surprisingly few open source communication robots.

We often see the tragedy of communication robots reaching the end of life as their backend services goes by.

"Why don't they make communication robots more open and hackable?" It is the problem and why Stackchan was born.

As a solution, I decided to create an open-source robot that anyone could build from scratch. This means that open community, rather than a closed, specific company or individual, will collaborate to grow the robot.

The most important feature of Stack-chan is that everything is open.

Stack-chan is open in two aspects. First, All the resources of Stack-chan are distributed under Apache-2.0 license, including the schematics, the 3D model of the case and the firmware. Second, I'm opening up not only the source code and model data for Stack-chan, but also the entire process of creating it. In other words, I shared widely the background issues, the decisions I made, the troubles I had, and the mistakes I made so that users can learn how to make and customize Stack-chan. You can follow the process by searching its official twitter hashtags.

#stackchan, #スタックチャン on Twitter

As a result, over 30 enthusiasts have already started making Stack-chan and putting them into their varius appilcations from frontend of voice assistant to quadrupedal robot. You can see the most impressive works from the community in my project logs. Over 200 tweets by them doing trial and error are in the curated list below.

Stack-chan - Togetter

System architecture

The robot consists of a case, an M5Stack and a dedicated expansion board, and firmware. Each component is fully customizable. The functionality as a communication robot is provided in the form of a framework, which users can easily access through applications (mods). M5Stack is equipped with wireless communication functions such as Wi-Fi and BLE, so it can be used with external services, smartphones, and other robots.

Detailed assembly instruction

The detailed assembly instructions are available on GitHub.

Lifelike behaviors

Stack-chan themselves has no special mission to solve. They just live. They have multiple communication modality such as speech and gaze. In despite of its small size, Stack-chan has a very lifelike appearance with its eyes and breathing. This behavior is achieved by simulating neurophysiological phenomena such as saccadic eye movements. But who cares the detail? It's just so cute. you can't stop loving it!

Unleash your creativity

Stack-chan is a kind of platform robot. While Stack-chan itself is quite simple in function, it can be used in various applications. For example:

  • A "sales robot" that finds people's faces and fiercely promotes products.
  • A "butler robot" with cute notifications of the day and Alexa functionality.
  • A "babysitting robot" that watches over children from their desk.

Sounds interesting? Fork my repositorylaunch dockernized environment in minutes and start making! Take advantage of many examples, especially for integration to external APIs and M5Stack units. Unfamiliar with embedded development? No problem. I choosed JavaScript, the world's most used programming language. Stack-chan's firmware is written on the Moddable SDK: a JavaScript framework for embedded systems. You can achieve brazing fast development with full of the latest ECMAScript features.

So what will you do with Stack-chan? Leave a comment and let's start...

Read more »

JPEG Image - 5.54 MB - 11/07/2021 at 05:18


JPEG Image - 1.76 MB - 11/07/2021 at 05:18


JPEG Image - 1.26 MB - 11/07/2021 at 05:18


JPEG Image - 706.75 kB - 11/07/2021 at 05:18


JPEG Image - 582.51 kB - 11/07/2021 at 05:18


View all 14 files

View all 18 components

  • Stack-chan Assembly Kits: Pre-order started!!

    Shinya Ishikawa07/11/2023 at 15:12 1 comment

    RT Corporation is going to release two versions of the Stack-chan assembly kit at the end of July! Starting from today, we have begun accepting pre-orders on our web store. We also offer international shipping.

    The options for the assembly kits include both the full kit containing the indispensable M5Stack for Stack-chan, and a version without the M5Stack.

    Please choose either of the two types according to whether you already have an M5Stack or not. The stocked-up kit arrives complete with a servo and battery, so you can start assembling your Stack-chan from the day it arrives.

    * M5Stack containing Stack-chan RT Ver.β Full Kit 25,300 yen (tax included).

    M5Stack-less Stack-chan RT Ver.β 18,150 yen (tax included).

    Corporate customers who wish to buy multiple items together, please contact us via the inquiry form.

    RT Corporation has recently been in the news with 'Foodly', a humanoid collaborative robot for food factories, but in the past, it has created a mascot robot 'Neko Tenchō' capable of hugging humans, positioning itself as a company with communication robots as one of its identities.

    We believe that selling Stack-chan from RT is very meaningful, as it aligns with RT's mission to "realize a lifestyle with robots". We hope that spreading Stack-chan will help to foster a culture of communication robot development in Japan and abroad.

    Meanwhile, Stack-chan is characterized by its open community. We aim for a relationship where everyone is a user and can also become a developer, rather than specific individuals or companies developing robots alone. We always look forward to seeing the culture of 'individual developers making unique improvements to the hardware and selling them as kits'.

    While I, the creator, am involved in the development of 'Stack-chan RT Ver.', it is not officially branded as such. We hope you will welcome it as one of the many Stack-chans. We're looking forward to seeing all of the 'best Stack-chan' creations you come up with and share.

    Of course, 'Stack-chan RT Ver.' will continue to be enhanced in the future. Let's enjoy creating it together!

  • Stack-chan is comming to the monthly Moddable Community Call

    Shinya Ishikawa05/08/2023 at 15:45 0 comments

    I'll be speaking at Moddable's online event on Friday, May 12th, at 8:00 PM PDT. I am developing Stack-chan's firmware using Moddable, a platform designed for embedded JavaScript.

    I plan to discuss Stack-chan's firmware at this online event, which the Moddable development team hosts monthly. I'll be sharing my motivations for using Moddable, details about Stack-chan's firmware, and particularly the source code for the ChatGPT integration that I introduced in my previous post. If you're interested, please feel free to join us!

    You can access more information at the following URL:

  • Introducing Stack-chan's Discord Server

    Shinya Ishikawa04/13/2023 at 15:58 0 comments

    The number of Stack-chan users has been steadily increasing, thanks to the integration with ChatGPT. As it has become challenging to keep up with all the information solely on Twitter, we decided to create a dedicated server. It's already bustling with over 100 participants!

    You can join using the URL below. Don't hesitate to participate!

    Everyone is welcome, whether you've already created a Stack-chan or are looking to create one soon.

  • ChatGPT x Stack-chan act.2

    Shinya Ishikawa04/13/2023 at 15:43 0 comments

    Aiming for a "Robot that Talks with People"

    One of my goals was to create a "robot that talks with people" through Stack-chan.

    Stack-chan is already cute without doing anything, but I have been working on development with the dream of a future where Stack-chan can provide advice to users, give praise and encouragement, and engage in playful communication with other Stack-chans.

    I had thought that it would take another 1-2 years to fully integrate dialogue management, but with the arrival of ChatGPT, I feel like the future has come in a giant leap!

    So, to achieve a "robot that talks with people," I've implemented and tested the ChatGPT integration feature!

    Read more »

  • Super Cute Pal-robot

    Shinya Ishikawa04/01/2023 at 15:05 0 comments
  • Monthly Stack-chan Updates: ChatGPT Collaboration, Kit Production, and More!

    Shinya Ishikawa03/24/2023 at 06:28 0 comments

    We've got some exciting news for you! Check out the latest updates on Stack-chan, which include a ChatGPT collaboration, kit production progress, and various community contributions.

    🤖 ChatGPT Collaboration: Thanks to a tweet by robo8080, Stack-chan is now gaining popularity through its collaboration with ChatGPT! Discover the tweet that sparked this partnership and explore some creative modifications of Stack-chan's character.

    🔧 Kit Production: We are working diligently to turn Stack-chan into a kit, responding to the enthusiasm generated by the ChatGPT collaboration. Stay tuned for detailed schedules and updates.

    🌟 Pull Requests & Development: The Stack-chan repository now has contributions from 10 people, and we welcome any contributions, no matter how small. Check out some of the latest developments, including configuration apps, tutorial videos, and more.

    🚀 Miscellaneous: From Stack-chan-themed sweaters to drone integrations, the community is getting more creative with their projects!

    Want to catch up on all the latest Stack-chan news? Read the full update in detail on GitHub discussion. If you have any Stack-chan information that you'd like to share, please post it in the thread!

    Don't miss out on any future Stack-chan updates! We'll be posting monthly updates on GitHub Discussions, so be sure to star and watch the repository to stay in the loop. Happy building!

  • From the community #10: Stack-chan and ChatGPT team up for an impressive AI chatbot demo

    Shinya Ishikawa03/07/2023 at 01:47 0 comments

    Have you ever wondered what would happen if you combined Stack-chan, the lovable robot, with ChatGPT, the AI chatbot? Well, wonder no more, because that's exactly what robo8080 did, and the results are pretty impressive.

    Read more »

  • Beggining commercialization for Stack-chan

    Shinya Ishikawa07/23/2022 at 15:12 0 comments

    There has been a long time since my last post. But Stack-chan development was never stopped.

    The number of Stack-chan developers is still increasing day by day and reached 100 on my Twitter list.

    This time, I decided to make a collaboration with my belonging company RT corporation to make Stack-chan's kit for beginners.

    Here is my blog post for the detail.

    (Poor machine translation warning! Stack-chan is misunderstood as "stack chain" 🙄)

    The kit includes an assembled board, 3D printed case, and everything to make Stack-chan without special equipment like a 3D printer or a soldering iron.

    I'm going to sell the kit first in Japan. I wonder how much demand there is for the kit abroad. Please let me know if you like to have it.

  • Stack-chan got the 2nd place of HackadayPrize!

    Shinya Ishikawa11/22/2021 at 14:14 0 comments

    I'm so excited to tell you that Stack-chan got the 2nd place of HackadayPrize!!

    Since I am not a native English speaker, I had prepared a script of greetings in case I needed to use it. But that is much longer than what I read out in the video. I'm posting it in its entirety as a memorial.

    Thank you HackadayPrize for giving me the honorable 2nd place.

    First of all, I would like to thank all members of the worldwide Stack-chan community. Without your passion and creativity, I wouldn't be standing here.
    Next, I'd like to thank Jimmy Lai and the M5Stack team. And thanks to Peter Hoddie and the ModdableSDK team.
    I couldn't have achieved the concept of a "cute robot that runs in JavaScript" without the help of their excellent devices and frameworks.
    Thank you SupplyFrame, Digikey and all HackadayPrize staffs for giving me the opportunity to share Stack-chan with the world.
    Finally, I would like to thank my wife and three children for their patience. I have dedicated almost all of my non-work time to Stack-chan. The kids have been Stack-chan's best playmates and also the most strict reviewers of new features. They can easily detect "childish tricks". They get bored so easily. I put a lot of effort into how to keep them happy.

    I am very lucky. In fact, I only started developing robots last year. Let me tell you a little about my story.

    I was doing research on human-robot interaction systems at university.
    However, for me, robots were something that I could buy and use, not something that I could build myself. Robot development and hardware hacking were things that I longed for, but also things that were far away.

    After a few setbacks, I joined a systems vendor and run into web development, forgetting about robots for a while. No, actually, I had many opportunities to recall them: Jibo, Vector, Robi or the new AIBO, LOVOT. As I watched the rise and fall of household robots, they remained distant to me, despite my growing longing for them.

    The trigger was the M5Stack. When I first got my hands on the M5Stack, I came up with the idea. "If I had a robot this size, it would be so cute!" The first thing I did was to write a library to display a simple face in M5Stack. Then the world changed. Makers from Japan and all over the world used the library to make various things. My maker spirit was sparked.

    Things accelerated from there. I moved to a robotics venture company, learned circuit design, CAD and ROS, got a 3D printer in my house. When I found out about ModdableSDK, my soul trembled because I realized that I might be able to put my JavaScript skills and web background to use in robotics development. Then it didn't take long for me to come up with the idea of "an open robot that anyone (even a web engineer like me, for example) can easily assemble and program.

    Looking back on my activities and its chain reaction, I am once again amazed at how simple the beginning was. I think I was "over-prepared" in the past when I gave up on robots. If I wanted to make a robot, the first thing I had to do was not to do research on robots at university. All I had to do was buy a motor and get it running.

    So again thank you to everyone who helped me realize this and encouraged to continue making.
    And I hope that Stack-chan can be a first step for people like me who are interested in robot development and for those who have once given up on robots.

    In recent years, robots have been playing an important role in many areas of society. An ever greater amount of money is being spent on robot development. I am afraid that this will lead to robot development being regarded as something privileged.

    We all know, essentially, we do not need a license or permission to develop robots except high voltage ones. I hope that Stack-chan will encourage as many people as possible to become interested in robot development and start creating robots. This is my dream.

    I will continue to develop Stack-chan so that it does not end...

    Read more »

  • From the community #9: Cardboard Stack-chan!

    Shinya Ishikawa11/18/2021 at 13:38 0 comments

    Kudos to ふるおらいと(@36kyo and 駿馬(@syumme01!

    They managed to make the Stack-chan case out of cardboard.

    Instead of doing 3D printing, ふるおらいと used regular cardboard to surround the M5Stack.

    It's hacky, but it just works! According to him, "I was disassembling my 3D printer for a move, so I just hacked it up with materials I had on hand."

    You want some chocolate?

    Inspired by this, 駿馬 further brushed up the structure of the bracket and other parts.


    The bracket is made up of three flat parts and is strong enough to be used.


    These examples are simple, yet very complete. I love them!
    It might be a good idea to distribute them as paper crafts.


    The experience of being able to magically create a robot with simple cardboard construction has the potential to lower the bar for robot development in one fell swoop, just as Google has done with Google Cardboard and AIY kits.

    These examples blew my mind, as I had been struggling with "what shape to make the 3D printed parts". I personally learned a lot from them:

    • the 3D printer I use everyday is still not the norm for many developers.
    • It is the core of creativity to devise ways to make things out of common materials.

    This is real hacker spirit, isn't it?

View all 34 project logs

View all instructions

Enjoy this project?



ChatGPT 日本語 GPTJP wrote 11/20/2023 at 06:35 point

Do you want to have conversations with an AI that seems like it's straight out of a science fiction movie? With ChatGPT 日本語, it's finally possible! ChatGPT 日本語 is the latest in natural language processing from, setting the standard for interactive artificial intelligence systems. Using OpenAI's cutting edge API, ChatGPT 日本語 can understand human language and engage in meaningful conversations with you -- without you having to register or even paying a penny. It's free and unlimited tokens can be used with ChatGPT anytime you want. 

  Are you sure? yes | no

M K wrote 11/21/2021 at 02:48 point

Congrats on your win today! So kawaii <3

  Are you sure? yes | no

Arnas MasRodjie wrote 09/05/2021 at 04:08 point

Can you post STEP files on the github? There are many SG90 servo model so they able to modify to fit the servo. Thank you

  Are you sure? yes | no

Shinya Ishikawa wrote 09/05/2021 at 15:45 point

Actually I have SG90 compatible case.

But it is a good idea to share STEP files. I'll deal with it later. Thank you very much! 

  Are you sure? yes | no

Shinya Ishikawa wrote 09/05/2021 at 17:03 point

Posted an issue:

  Are you sure? yes | no

Shinya Ishikawa wrote 11/02/2021 at 17:57 point

Now I'm posting a STEP files of the cases totally refined. SG90 versions of them will be available soon!

  Are you sure? yes | no

Maximiliano Rojas wrote 08/31/2021 at 01:58 point

kawai XDD

  Are you sure? yes | no

Shinya Ishikawa wrote 09/04/2021 at 16:58 point

Thanks you! As I posted, you can check many Stack-chan works by me and other developers on Twitter. Hope you also like them!

  Are you sure? yes | no

Similar Projects

Does this project spark your interest?

Become a member to follow this project and never miss any updates