particular_min.rb

require 'uart'
require 'io/wait'

class Sample < Struct.new(:time,
                          :pm1_0_standard, :pm2_5_standard, :pm10_standard,
                          :pm1_0_env,      :pm2_5_env,
                          :concentration_unit,
                          :particle_03um,   :particle_05um,   :particle_10um,
                          :particle_25um,   :particle_50um,   :particle_100um)
end

uart = UART.open ARGV[0], 9600, '8N1'

p Sample.members # header

loop do
  uart.wait_readable
  start1, start2 = uart.read(2).bytes

  # According to the data sheet, packets always start with 0x42 and 0x4d
  unless start1 == 0x42 && start2 == 0x4d
    # skip a sample
    uart.read
    next
  end

  length = uart.read(2).unpack('n').first
  data = uart.read(length)
  crc  = 0x42 + 0x4d + 28 + data.bytes.first(26).inject(:+)
  data = data.unpack('n14')

  next unless crc == data.last # crc failure

  p Sample.new(Time.now.utc, *data.first(12)).to_a
end