Infra Red Library

Infra Red Capture, Send and Decode module

This module contains class definitions and methods to capture, decode and send IR packets.

  • The IRPacket class allows the definition of IRPacket objects.
  • The IRReceiver class allows the definition of an IR capture unit based on an IR receiver and demodulator connected to a pin empowered with ICU feature.
  • The IRSender class allows the definition of an IR sender based on an IR LED connected to a pin endowed with PWM feature.

IRPacket class

class IRPacket(packet_type, addr1, addr2, d1, d2, hexd, rawdata, databits)

This is the class that allows the definition of IR messages/packets

Attributes:

  • packet_type: it is a string identifying the packet IR protocol of the message. Currently the following packets are supported: SAMSUNG, NEC and UNKNOWN.
  • addr1: it is the first address data packet (to be set to 0 if not supported by the selected protocol)
  • addr2: it is the second address data packet (to be set to 0 if not supported by the selected protocol)
  • d1: it is the first message data packet
  • d2: it is the second message data packet (to be set as 0 if not supported by the selected protocol)
  • hexd: it is the Hexadecimal string representing the data contained in d1 and d2
  • rawdata: it is a list of int containing the raw data acquired by the transducer during the acquisition of the packet. Data are listed as int representing the duration in microseconds of a “pulse state” the first reported time is an HIGH pulse duration, the second is the duration of the following LOW pulse and so on.
  • databits: is a list of strings “0” or “1” representing the boolean decode of rawdata obtained through the decoder selected according to the packet_type

IrPacket instances are generated by the infrared.decode() and are taken as input by the IRSender.send() methods.

printPacket(stream)

generates a Print-friendly and readable output containing the packet data and print it on the selected stream.

IRReceiver class

class IRReceiver(IrRecvPin)

This is the class that allows definition of an IR receivers made by using an IR demodulator.

IrRecvPin: The pin connected with the IR demodulator. The pin have to be endowed with ICU functionality and passed using the Dx.ICU signature.

decode(data)

Analyzes the raw captured data identifying the protocol.

If the protocol is recognized data are decoded and an IRPacket returned. Otherwise an IRPacket with packet_type “UNKNOWN” is returned

capture(max_samples=100, time_window=200, wait=0)

Starts the IR capture activating the ICU on the receiver pin.

  • max_samples: it sets the number of samples to be collected before terminate the capture. Default is set to 100 that works for most of the used IR protocols.
  • time_window: it sets the max amount in milliseconds of the capture window. Default is set to 200 milliseconds that works for most of the used IR protocols.
  • wait: it allows the definition of a sleeping time in millisecond to be waited after a capture in order to avoid capturing repeated packets as partial raw data.

Consider that air conditioning remote controller IR packets are very long therefore these values have to be tuned according to the desired application.

The method returns raw captured data packet that can be used as input for IRSender.sendRaw() or decoded using IRReceiver.decode()

captureAndDecode(max_samples=100, time_window=200, wait=0)

Starts the IR capture activating the ICU on the receiver pin and pass the captured raw signal to the decode method returning an IRPacket

  • max_samples: it sets the number of samples to be collected before terminate the capture. Default is set to 100 that works for most of the used IR protocols.
  • time_window: it sets the max amount in milliseconds of the capture window. Default is set to 200 milliseconds that works for most of the used IR protocols.
  • wait: it allows the definition of a sleeping time in millisecond to be waited after a capture in order to avoid capturing repeated packet as partial raw data.

Consider that air conditioning remote controller IR packets are very long therefore these values have to be tuned according tot the desired application.

The method returns an IRPacket.

IRSender class

class IRSender(IRSenderPin, Frequency=38000, Duty=30)

This is the class that allows the definition of an IR sender made by connecting and IR LED to a pin endowed with PWM.

  • IRSenderPin: it is the pin where the LED is connected. Have to be passed specifying the PWM feature i.e, D3.PWM
  • Frequency: it is the IR pulse modulation frequency. default is set to 38000 Hz that is the most used standard.
  • Duty: It is the duration in percentage 0-100 of the IR pulse. The duty definition allows reducing power consumption avoiding long pulses. Default is set to 30 while values in the range 20-50 can be used.

The class has two methods for sending respectively raw data and IRPacket.

sendRaw(data)

Sends raw data by taking as input a list of pulses duration in microseconds. The first represents the duration of IR firing phase (state 1) while the the second is the IR LED OFF phase (state 0) and so on.

send(IRPacket)

Sends the IR message contained in the passed IRPacket. If IRPacket packet_type is UNKNOWN data are sent as raw data.