SenseHat - WIP

I prefer working with Ruby, so here's a Ruby interface for the raspberry-pi sensehat.

Features

TODO list of supported features

### Display
[x] clear  
[x] set pixels  
[x] get pixels  
[ ] set pixel  
[ ] get pixel  
[ ] rotation  
[ ] flip_h  
[ ] flip_v  
[ ] load_image  
[ ] show_message  
[x] show_letter  

### Environment
[ ] humidity  
[ ] temp from humidity  
[ ] pressure  
[ ] temp from pressure  

### IMU Sensor
[ ] compass  
[ ] gyro  
[ ] acceleration

Installation

On your raspberry-pi (make sure you have ruby installed!)

pi@raspberrypi:~/Scripts/test $ echo "gem 'sense_hat', git: 'https://github.com/rjlynch/ruby-sense-hat'" >> Gemfile
pi@raspberrypi:~/Scripts/test $ bundle

Fire up irb and require bundler set up and the gem

pi@raspberrypi:~/Scripts/test $ irb
irb(main):001:0> require 'bundler/setup'
irb(main):002:0> require 'sense_hat'

Then have a play around!
The below snippet will make the LED display all green.

irb(main):003:0> display = SenseHat::Display.new
=> #<SenseHat::Display:0x01644ea0 @device=#<SenseHat::Display::Device:0x01644e88 @device_path="/dev/fb1">>
irb(main):004:0> display.set_pixels Array.new(64) { [0, 255, 0] }
irb(main):005:0> display.clear
irb(main):006:0> exit

Usage

Initialize a display object

  display = SenseHat::Display.new

Clear the display

  display.clear

Setting the display

Pass a 64 element array of RGB colour values to set_pixels.
Each pixel is represented as an array of 3 integers in the range 0..255 indicating it's RGB value.
The below example would set the whole display to red.

  display.set_pixels([
    [255, 0, 0],
    [255, 0, 0],
    ...
    [255, 0, 0]
  ])

show_letter displays a single character on the LED display.
It accepts optional keyword args for setting the colour and background.

  display.show_letter 'A'
  display.show_letter 'A', colour: [0, 0, 0], background: [248, 252, 248]

Reading the display

get_pixels will return the colour values of each LED.
Due to the RGB565 encoding the max value returned for red or blue will be 248 and for green the max value will be 252.
See this stackoverflow answer for more information.

  display.get_pixels # => [[248, 0, 0], [248, 0, 0], ...  [248, 0, 0] ]

Development

After checking out the repo, run bin/setup to install dependencies. Then, run rake spec to run the tests. You can also run bin/console for an interactive prompt that will allow you to experiment.

To install this gem onto your local machine, run bundle exec rake install. To release a new version, update the version number in version.rb, and then run bundle exec rake release, which will create a git tag for the version, push git commits and tags, and push the .gem file to rubygems.org.

Contributing

Bug reports and pull requests are welcome on GitHub at https://github.com/rjlynch/sense_hat.

License

The gem is available as open source under the terms of the MIT License.

rjlynch / ruby-sense-hat