Class: DHT11::Sensor

Inherits:
Object
  • Object
show all
Defined in:
lib/dht11.rb

Instance Method Summary collapse

Constructor Details

#initialize(pin, tries: 10, interval: 0.1) ⇒ Sensor

Returns a new instance of Sensor.



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# File 'lib/dht11.rb', line 21

def initialize(pin, tries: 10, interval: 0.1)
  @pin = pin
  @tries = tries
  @interval = interval
  RPi::GPIO.set_numbering(:bcm)
end

Instance Method Details

#read ⇒ Object 



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# File 'lib/dht11.rb', line 28

def read
  @tries.times do 
    @last_result = read_once
    return @last_result if @last_result.valid?
    sleep @interval
  end
  @last_result
end

#read_once ⇒ Object 



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# File 'lib/dht11.rb', line 37

def read_once
  send_initial_signal
  raw_inputs = collect_raw_input
  periods = parse_inputs_into_pull_up_periods(raw_inputs)
  if periods.length != 40
    return Result.new(Err::MISSING_DATA, Float::NAN, Float::NAN)
  end
  bits = calculate_bits(periods)
  bytes = bits_to_bytes(bits)
  checksum = calculate_checksum(bytes)
  if bytes[4] != checksum
    return Result.new(Err::CRC, Float::NAN, Float::NAN)
  end

  temperature = bytes_to_temperature(bytes).to_f
  humidity = bytes_to_humidity(bytes).to_f
  Result.new(Err::NO_ERROR, temperature, humidity)
end