ruby script that grab pictures from LinkSprite TTL JPEG camera

linksprite_jpeg_camera.rb

require 'serialport'
require 'colored'
require 'ruby-progressbar'

class Y201Grab

  def self.a2s(*arr)
    arr.pack 'c*'
  end

  LK_RESET          = a2s(0x56, 0x00, 0x26, 0x00)
  LK_RESET_RE       = a2s(0x76, 0x00, 0x26, 0x00, 0x00)
  LK_PICTURE        = a2s(0x56, 0x00, 0x36, 0x01, 0x00)
  LK_PICTURE_RE     = a2s(0x76, 0x00, 0x36, 0x00, 0x00)
  LK_JPEGSIZE       = a2s(0x56, 0x00, 0x34, 0x01, 0x00)
  LK_JPEGSIZE_RE    = a2s(0x76, 0x00, 0x34, 0x00, 0x04, 0x00, 0x00) # then XH XL
  LK_STOP           = a2s(0x56, 0x00, 0x36, 0x01, 0x03)
  LK_STOP_RE        = a2s(0x76, 0x00, 0x36, 0x00, 0x00)
  LK_READPICTURE    = a2s(0x56, 0x00, 0x32, 0x0C, 0x00, 0x0A, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00) #then KH KL
  LK_PICTURE_TIME   = a2s(0x00, 0x0A) # .1 ms
  LK_READPICTURE_RE = a2s(0x76, 0x00, 0x32, 0x00, 0x00)
  JPEG_START        = a2s(0xFF, 0xD8)
  JPEG_END          = a2s(0xFF, 0xD9)
  LK_PIC_SIZE_640   = a2s(0x56, 0x00, 0x31, 0x05, 0x04, 0x01, 0x00, 0x19, 0x00)
  LK_PIC_SIZE_320   = a2s(0x56, 0x00, 0x31, 0x05, 0x04, 0x01, 0x00, 0x19, 0x11)
  LK_PIC_SIZE_160   = a2s(0x56, 0x00, 0x31, 0x05, 0x04, 0x01, 0x00, 0x19, 0x22)
  LK_PIC_SIZE_RE    = a2s(0x76, 0x00, 0x31, 0x00, 0x00)
  LK_BAUD_RATE      = a2s(0x56, 0x00, 0x24, 0x03, 0x01)
  LK_BAUD_RATE_RE   = a2s(0x76, 0x00, 0x24, 0x00, 0x00)

  attr_reader :serial

  def grab_pic
    SerialPort.open("/dev/ttyACM0", 38400, 8, 1, SerialPort::NONE) do |ser|
      @serial = ser
      ser.read_timeout = 100 #ms

      info "reseting"
      reset

      sleep 2

      info "picture"
      take_picture

      info "size"
      check_size do |size|
        fetch_data( size ) do |data|
          File.open( 'output.jpg', 'w' ) do |f|
            info "write into #{f.path}"
            f << data
            debug "done"
          end
        end
      end
    end
  end

  def reset
    serial.flush_input
    serial.write LK_RESET
    sleep 0.1
    check_response_with! LK_RESET_RE
  end

  def stop
    serial.flush_input
    serial.write LK_STOP
    sleep 0.1
    check_response_with! LK_STOP_RE
  end

  def check_response_with! expect
    serial.read( expect.size ).tap do |res|
      if res != expect
        debug "fail, got: #{res.inspect}"
        debug "   expect: #{expect.inspect}"
        raise "failed"
      else
        debug "done"
      end
    end
  end

  def set_size( size )
    serial.flush_input
    serial.write LK_PIC_SIZE_640
    sleep 0.1
    check_response_with! LK_PIC_SIZE_RE
  end

  def take_picture
    serial.flush_input
    serial.write LK_PICTURE
    sleep 0.5
    check_response_with! LK_PICTURE_RE
  end

  def check_size
    serial.flush_input
    serial.write LK_JPEGSIZE
    sleep 0.5
    check_response_with! LK_JPEGSIZE_RE
    xh = serial.read(1).unpack('C*').first
    xl = serial.read(1).unpack('C*').first
    (xh * 256 + xl).tap do |size|
      yield size if block_given?
    end
  end

  def fetch_data size
    info "fetch JPEG data (#{size}byte)"

    kh = (size >> 8) & 0xFF
    kl = size & 0xFF

    serial.flush_input
    serial.write LK_READPICTURE + self.class.a2s(kh, kl) + LK_PICTURE_TIME
    sleep 0.05

    debug "check ready signal"
    check_response_with! LK_READPICTURE_RE

    debug "begin reading JPEG"
    progress_bar = ProgressBar.create(
        :format         => '%a %bᗧ%i %p%% %t',
        :progress_mark  => ' ',
        :remainder_mark => '･'
    )

    picture = ""
    read_size = 0

    while true do
      chunk = serial.read(2)
      read_size += chunk.size
      picture += chunk
      progress_bar.progress = read_size.to_f / size * 100
      break if chunk == JPEG_END
    end

    progress_bar.clear
    debug "#{read_size} of #{size} read"
    debug "data size: #{picture.size}"


    picture.tap do
      debug "done reading"
      yield picture if block_given?
    end

  end

  private

    def info msg
      puts section << msg
    end

    def section
      "---> "
    end

    def debug msg
      puts indent << msg.black
    end

    def indent
      " " * 5
    end

end

Y201Grab.new.grab_pic