Class: MovingsignApi::Sign

Inherits:
Object
  • Object
show all
Defined in:
lib/movingsign_api/sign.rb

Overview

Manipulates a Movingsign attached to a serial port

Examples:

Construct a sign

require 'movingsign_api'

sign = MovingsignApi::Sign.new('/dev/ttyUSB0')

Show Text

sign.show_text('Hello World!')

Turn Sound Off

sign.set_sound false

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(device_path) ⇒ Sign 



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# File 'lib/movingsign_api/sign.rb', line 22

def initialize(device_path)
  @device_path = device_path
end

Instance Attribute Details

#device_path ⇒ Object

Serial port device path (ie: /dev/ttyUSB0)



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# File 'lib/movingsign_api/sign.rb', line 19

def device_path
  @device_path
end

Instance Method Details

#send_command(command) ⇒ self

Sends the specified Movingsign command to this sign’s serial port



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# File 'lib/movingsign_api/sign.rb', line 70

def send_command(command)
  SerialPort.open(self.device_path, 9600, 8, 1) do |port|
    # flush anything existing on the port
    port.flush
    flush_read_buffer(port)

    byte_string = command.to_bytes.pack('C*')

    begin
      while byte_string && byte_string.length != 0
        count = port.write_nonblock(byte_string)
        byte_string = byte_string[count,-1]

        port.flush
      end
    rescue IO::WaitWritable
      if IO.select([], [port], [], 5)
        retry
      else
        raise IOError, "Timeout writing command to #{self.device_path}"
      end
    end

    # wait for expected confirmation signals
    got_eot = false
    got_soh = false
    loop do
      begin
        c = port.read_nonblock(1)

        case c
          when "\x04"
            if ! got_eot
              got_eot = true
            else
              raise IOError, "Got EOT reply twice from #{self.device_path}"
            end
          when "\x01"
            if got_eot
              if ! got_soh
                got_soh = true

                break
              else
                raise IOError, "Got SOH twice from #{self.device_path}"
              end
            else
              raise IOError, "Got SOH before EOT from #{self.device_path}"
            end
        end
      rescue IO::WaitReadable
        if IO.select([port], [], [], 3)
          retry
        else
          raise IOError, "Timeout waiting for command reply from #{self.device_path}.  EOT:#{got_eot} SOH:#{got_soh}"
        end
      end
    end
  end

  self
end

#set_sound(on) ⇒ self

Turns on/off sound when the sign receives a command

This is a shorthand for MovingsignApi::SetSoundCommand



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# File 'lib/movingsign_api/sign.rb', line 59

def set_sound(on)
  cmd = SetSoundCommand.new on

  send_command cmd
end

#show_identity ⇒ Object

Show the #device_path value on the display (useful for diagnostics)



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# File 'lib/movingsign_api/sign.rb', line 27

def show_identity
  cmd = WriteTextCommand.new
  cmd.text = self.device_path

  send_command cmd
end

#show_text(text, options = {}) ⇒ self Also known as: write_text

Displays the given text on the board.

This is short-hand for the WriteTextCommand

Options Hash (options):



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# File 'lib/movingsign_api/sign.rb', line 43

def show_text(text, options = {})
  cmd = WriteTextCommand.new
  cmd.display_pause = options[:display_pause] if options[:display_pause]
  cmd.text = text

  send_command cmd
end