mvidner / lignite

Program LEGO Mindstorms EV3 in Ruby

Lignite: Program LEGO Mindstorms EV3 in Ruby

Lignite is a set of Ruby tools to interact with LEGO Mindstorms EV3. It uses the original LMS2012 firmware, so ev3dev is not required.

At this point the tools are still rather a thin wrapper so it will be useful to have the EV3 Firmware Developer Kit and EV3 Communication Developer Kit documents at hand for reference: see the "Advanced Users – Developer Kits" section of the Mindstorms Downloads page.

Features

• Connect via USB or Bluetooth
• Execute Direct Commands
• Execute System Commands, including
  • Upload RBF programs
  • Run RBF programs
• Compile Ruby into RBF programs
• Supported platforms: Linux (bug reports or pull requests for Windows or Mac are also welcome)

Getting Started

Running the built-in demo program: Connect the brick with a USB cable. Run

sudo ev3tool start BrkProg_SAVE/Demo.rpf

In the usual case where the folder and the program name are the same, a shortcut works: ev3tool start everstorm is like ev3tool start everstorm/everstorm.rbf.

The sudo is needed to access the USB device. With udev you can configure the system to allow access to all users like this:

echo 'SUBSYSTEM=="usb", ATTRS{idVendor}=="0694", ATTRS{idProduct}=="0005", MODE="0666"' \
  | sudo tee /etc/udev/rules.d/99-org-rubygems-lignite-lego-ev3.rules

To connect with Bluetooth, configure the address and pair the device (FIXME: how; troubleshooting?)

See also the included examples.

Hello World

require "lignite"
dc = Lignite::DirectCommands.new
dc.ui_draw_clean
dc.ui_draw_text(Lignite::FG_COLOR, 20, 40, "Hello, world!")
dc.ui_draw_update

Acknowledgements

Thanks to David Lechner of the ev3dev project for the ev3.yml bytecodes file.

lignite's Issues

udev rules

You can avoid the need for sudo by creating a udev rule

echo SUBSYSTEM=="usb", ATTRS{idVendor}=="0694", ATTRS{idProduct}=="0005", MODE="0666"' > sudo tee /etc/udev/rules.d/99-lego.rules

Error when btaddr config file does not exist

Using lignite 0.1.0 installed from gem.

When running ev3tool with no USB attached, I get the following error:

/home/david/.rbenv/versions/2.1.7/lib/ruby/gems/2.1.0/gems/lignite-0.1.0/lib/lignite/connection/bluetooth.rb:24:in `read': No such file or directory @ rb_sysopen - /home/david/.config/lignite-btaddr (Errno::ENOENT)
        from /home/david/.rbenv/versions/2.1.7/lib/ruby/gems/2.1.0/gems/lignite-0.1.0/lib/lignite/connection/bluetooth.rb:24:in `address_from_file'
        from /home/david/.rbenv/versions/2.1.7/lib/ruby/gems/2.1.0/gems/lignite-0.1.0/lib/lignite/connection/bluetooth.rb:10:in `initialize'
        from /home/david/.rbenv/versions/2.1.7/lib/ruby/gems/2.1.0/gems/lignite-0.1.0/lib/lignite/connection.rb:8:in `new'
        from /home/david/.rbenv/versions/2.1.7/lib/ruby/gems/2.1.0/gems/lignite-0.1.0/lib/lignite/connection.rb:8:in `rescue in create'
        from /home/david/.rbenv/versions/2.1.7/lib/ruby/gems/2.1.0/gems/lignite-0.1.0/lib/lignite/connection.rb:5:in `create'
        from /home/david/.rbenv/versions/2.1.7/lib/ruby/gems/2.1.0/gems/lignite-0.1.0/lib/lignite/system_commands.rb:8:in `initialize'
        from /home/david/.rbenv/versions/2.1.7/lib/ruby/gems/2.1.0/gems/lignite-0.1.0/bin/ev3tool:58:in `new'
        from /home/david/.rbenv/versions/2.1.7/lib/ruby/gems/2.1.0/gems/lignite-0.1.0/bin/ev3tool:58:in `<top (required)>'
        from /home/david/.rbenv/versions/2.1.7/bin/ev3tool:23:in `load'
        from /home/david/.rbenv/versions/2.1.7/bin/ev3tool:23:in `<main>'

running files

Two suggestions when running files with ev3tool run.

1. Show an error message if the file does not exist.
2. Don't make me have to know about ../prjs/. Just have the user type the path that is on the screen of the EV3 and add ../prjs/ internally in ev3tool.

Error when no bluetooth adapter

I don't have built-in bluetooth, so after creating the bluetooth address config file, I get the following error

/home/david/.rbenv/versions/2.1.7/lib/ruby/gems/2.1.0/gems/lignite-0.1.0/lib/lignite/connection/bluetooth.rb:19:in `connect': No route to host - connect(2) for unknown address family 31 (Errno::EHOSTUNREACH)
        from /home/david/.rbenv/versions/2.1.7/lib/ruby/gems/2.1.0/gems/lignite-0.1.0/lib/lignite/connection/bluetooth.rb:19:in `initialize'
        from /home/david/.rbenv/versions/2.1.7/lib/ruby/gems/2.1.0/gems/lignite-0.1.0/lib/lignite/connection.rb:8:in `new'
        from /home/david/.rbenv/versions/2.1.7/lib/ruby/gems/2.1.0/gems/lignite-0.1.0/lib/lignite/connection.rb:8:in `rescue in create'
        from /home/david/.rbenv/versions/2.1.7/lib/ruby/gems/2.1.0/gems/lignite-0.1.0/lib/lignite/connection.rb:5:in `create'
        from /home/david/.rbenv/versions/2.1.7/lib/ruby/gems/2.1.0/gems/lignite-0.1.0/lib/lignite/direct_commands.rb:5:in `initialize'
        from hello.rb:4:in `new'
        from hello.rb:4:in `<main>'

A friendly error message, such as "no Bluetooth or USB devices found", would be better.

Using code completion in VSCode with Ruby extension (rebornix.ruby) causes motors to run

Steps to repeat:

1. install Visual Studio Code
2. install Ruby extension in VSCode
3. install lignite 0.1.0 from gem
4. install rcodetools from gem for code completion
5. open the motor demo in VSCode
6. Run the demo from a command line to make sure communication to robot is working
7. Place cursor on the end of the line dc.output_ready(layer, nos)
8. Press CTRL+SPACE for code completion
9. The motors run briefly!