Control air purifier by servo motor (Panasonic F-VX501)

air_purifier.rb

def initialize_state
  $mode_state_file = "#{__dir__}/mode_state_file"
  $power_state_file = "#{__dir__}/power_state_file"
  update_mode_state(1) unless FileTest.exist?($mode_state_file)
  update_power_state(1) unless FileTest.exist?($power_state_file)
  $mode_state = File.read($mode_state_file).to_i
  $power_state = File.read($power_state_file).to_i
  $mode_name = ["low", "mid", "high", "auto"]
end

def change_air_flow(target_mode)
  n = target_mode - $mode_state
  n = n + $mode_name.size if n.negative?

  puts "#{$mode_name[$mode_state]} => #{$mode_name[target_mode]}"
  puts n

  mode_push(n)
  update_mode_state(target_mode)
end

def power_change(t)
  power_push unless $power_state == t
  update_power_state(t)
end

def mode_push(n)
  n.times do 
    puts "mode push!"
    left_turn
    sleep 1
    init_position
    sleep 1
  end
end

def power_push
  puts "power push!"
  right_turn
  sleep 1
  init_position
  sleep 1
end

def update_mode_state(state)
  File.open($mode_state_file,"w") {|f|f.print state }
end

def update_power_state(state)
  File.open($power_state_file,"w") {|f|f.print state }
end

def right_turn
  `echo 0=70% > /dev/servoblaster`
end

def left_turn
  `echo 0=35% > /dev/servoblaster`
end

def init_position
  `echo 0=50% > /dev/servoblaster`
end


function = ARGV[0]
target = ARGV[1]
initialize_state

unless target.match(/[0123]/)
  puts "ERROR: target number is 0-3"
  exit
end

target = target.to_i

if function == "power"
  power_change(target)
elsif function == "mode"
  power_change(1) if $power_state == 0
  change_air_flow(target)
else
  puts "ERROR: function is power or mdoe"
end