Segway-like robot implemented on ESP8266
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A segway-like balancing two-wheel robot built on ESP8266. It is controlled over WiFi via a HTML/JS GUI and a WebSocket. This is a work in progress. The firmware is meant to run on a WEMOS D1 mini or a similar board.

NOTE for existing users: the Arduino version of this code is deprecated and will not receive the newest improvements from the main branch. However, the Arduino branch will remain in this repo. If you'd like to have something improved or fixed there, please open an issue or preferably a pull request.

Getting started

The firmware is built on the esp-open-rtos project which is included as a submodule in this repo.

For building the firmware, a Linux host is recommended. For other platforms, there is a Docker image one can use. The docker-run script in this repository contains the command that's required to download the image and run commands in the container. It should work fine on macOS hosts. For Windows hosts, I still recommend installing Linux in a virtual machine and installing the tools there.

Installing the tools and building

NOTE: if you intend to use Docker, you only have to install esptool, git and make on your host. Please see below for further Docker instructions.

Install these packages:

  • git (from your package manager)
  • xtensa-lx106-elf toolchain. You can use esp-open-sdk to build it, see the instructions in the esp-open-rtos repo
  • esptool (pip install -U esptool). Please do not use the outdated version pulled by esp-open-sdk.
  • tcc, nodejs and npm are currently required due to the frontend code, although I'm investigating how to relax this dependency.

Clone this repo (recursive cloning to get also esp-open-rtos and its submodules):

git clone --recursive

Enter the directory and build the firmware:

make parallel

The parallel target does a clean build with 5 parallel worker threads to make it faster.

Plug your ESP8266 module in via USB and flash the firmware:

make flash

The default port is /dev/ttyUSB0. If you need to change this, use

make flash ESPPORT=/dev/ttyUSBx

Using the Docker image

First, install Docker.

Building the firmware using the supplied Docker image is easy. Instead of running make parallel, just run ./docker-run make parallel in the root folder of the repo. The command supplied to the script will be run in the Docker container, and the image will be automatically downloaded.

Flashing the image differs, though, and for this you'll need make on your host. Instead of

make flash ESPPORT=/dev/ttyUSBx

(/dev/ttyUSBx being the ESP's serial port) run

make flash-only ESPPORT=/dev/ttyUSBx

in your host shell. The separate flash-only target is needed because the flash target would try to build the firmware. In the future, it is intended to provide a separate Python script for flashing, lifting the need for make on host.

Supported browsers

Please use the latest Firefox or Chrome if possible. The HTML/JS UI uses some recent JavaScript features which might not be supported by older browsers. However if you encounter any issues on e.g. Safari, don't hesitate to file them in the issue tracker.

Schematic & BOM

There is a PCB design and schematic in the schematic folder which has been tested and is ready to use. There, MPU6050 has been replaced by LSM6DS3 and L293D by DRV8835 for better performance.

Meanwhile, you can still build an ESPway using breakout boards available from the usual sources. A rough bill of materials for this is listed below:

  • (not including PCB, connectors, wire etc. materials)
  • WEMOS D1 Mini board
  • GY-521 (MPU6050 breakout board)
  • L293D motor driver IC
  • 2x 6V 300rpm metal gear motor (search for "12ga 300rpm" or "n20 300rpm"), these should be $3-5 per piece
  • 2x WS2812B neopixels for eyes and showing current state
  • AMS1117 5V regulator
  • 5x 100n ceramic capacitors
  • 2x 1000u 10V electrolytic capacitor
  • 470 ohm resistor
  • 10 kohm resistor
  • 680 kohm resistor

To use the old hardware config and schematic, you'll have to edit src/espway_config.h before compilation. See that file for notes.

See the schematic-old folder for the schematic. It is drawn with KiCad and there's a rendered PDF in the repo.

The new schematic in schematic folder uses components from kicad-ESP8266 by J. Dunmire, licensed under CC-BY-SA 4.0. The schematic is also licensed under CC-BY-SA 4.0.

Developing the frontend

The HTML/JS frontend uses Webpack as the build system. You will need NodeJS and NPM (the package manager) to build the frontend pages. It does jobs like bundling the JavaScript modules together, minifying and transpiling the ES2015 code for older browsers, compiling Riot tags, minifying/autoprefixing CSS etc.

After you've cloned this repo, run npm install in the root folder to install the package dependencies. There are two commands specified in package.json which run Webpack:

  • npm run serve start a web server which serves the static HTML files in the frontend/output directory. It also watches for changes in the source files in frontend/src and automatically rebuilds and reloads them. Use this while hacking on the frontend. TODO: Currently this doesn't see changes to HTML files, though.
  • npm run build produces a production build of the frontend JS/CSS bundles. Use this before uploading your work to the ESP8266.

License and acknowledgements

The project is licensed under LGPLv3.

The project uses esp-open-rtos which is licensed under the BSD 3-clause license. It also has some components which have different licenses. Read more about them in the esp-open-rtos README.