dino-piboard

dino-piboard 0.13.0

This is an add-on to the dino gem. It adds support for the GPIO interface on Raspberry Pi single board computers. Unlike the main dino gem, which connects a computer running Ruby to an external microcontroller, this requires only a Pi.

Dino::PiBoard gives access to the Pi's own GPIO, and is a drop-in replacement for Dino::Board, which would represent an external microcontroller.

Note: This is not for the Raspberry Pi Pico (W) / RPP2040. That microcontroller is covered by the main gem.

Installation

Note: This gem is very new. It WILL NOT work with the version of dino (0.11.3) currently available on rubygems.org. Before installing dino-piboard, make sure to install the latest dino version (future 0.13.0) from the master branch source.

Install dino from source:

sudo gem uninstall dino
git clone https://github.com/austinbv/dino.git
cd dino
gem build
sudo gem install dino-0.13.0.gem

Install the pigpo C library:

sudo apt-get install pigpio

Install this gem:

sudo gem install dino-piboard

Example

Create a script, led_button.rb:

require 'dino/piboard'

# Create a board instance for the Raspberry Pi.
board = Dino::PiBoard.new

# LED connected to GPIO4.
led = Dino::LED.new(board: board, pin: 4)

# Momentary button connected to GPIO17, using internal pullup.
button = Dino::DigitalIO::Button.new(board: board, pin: 17, pullup: true)

# Led on when button is down (0)
button.down do
  puts "Button down"
  led.on
end

# Led is off when button is up (1)
button.up do
  puts "Button up"
  led.off
end

# Sleep main thread. Ctrl+C to quit.
sleep

Run the script as root (pigpio can only be used as root):

sudo ruby led_button.rb

See examples in the main gem for more. Remove any Dino::Board::Connection and Dino::Board objects that the script sets up, and do board = Dino::PiBoard.new instead. Not all features are implemented yet though, nor can be implemented. See Feautres below.

How It Works

This gem uses the pigpio_ffi gem, which in turn uses ffi to map the functions of the pigpio C library. pigpio provides low-level access to the Raspberry Pi's GPIO interface.

Building on that, Dino::PiBoard plugs in as a (mostly) seamless replacement for Dino::Board. This allows dino features and component classes to be used directly on a Raspberry Pi, without an external microcontroller.

Features

Already Implemented

• Internal Pull Down/Up
• Digital Out
• Digital In
• PWM Out

To Be Implemented

• Tone Out
• Servo
• I2C
• SPI
• OneWire
• Infrared Out

Won't Be Implemented

• UART. It would wrap a rubyserial instance. Use that directly instead.

Might Be Different

• Variable Digital Listen Timing (pigpio doesn't have a real way to do this, but glitch filter might be even better?)

Incompatible

• Handshake (no need, since running on the same board)
• EEPROM (can't mess with that. Use the filesystem instead)
• Analog IO (No analog pins on Raspberry Pi. Use an ADC or DAC over I2C or SPI)