Monthly Archives: December 2014

Reverse engineering the Panasonic AC Infrared protocol

Recently, two of our users in France (Vincent & Mathieu) collaborated to reverse engineer the Panasonic AC Infrared protocol, one of the more challenging AC Infrared protocols using AnalysIR. Not only did they identify the codes & checksum but also provided some impressive documentation and full source code to help others. Detailed information is available via GitHub which is linked below. This 216 data bit Panasonic AC Infrared protocol is composed of two consecutive frames. The first frame remains constant for every command sent to the AC unit. In common with most AC units the complete configuration is sent with every IR signal (temperature, fan, swing etc…). AnalysIR was used to record and turn the signal into HEX/Binary format from which the reverse engineering of the individual fields was tackled.

AnalysIR - Panasonic AC 216 bit Infrared signal
AnalysIR – Panasonic AC 216 bit Infrared signal

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Infrared receiver showdown – TSOP34438 vs VS1838B winner revealed

Having helped many makers resolve problems with Infrared remote control projects over on the Arduino forum, we decided to put 2 of the more common 38kHz receivers, TSOP34438 vs VS1838B,  ‘head-to-head’ over 3 rounds in a winner takes all contest. Different people report a wide variety of problems when first attempting infrared remote control, resulting from using the wrong receiver to timer or interrupt conflicts between the various libraries available. Our commentary on the ‘face-off’ will hopefully shed some light on the ability of these 2 common Infrared receivers to deliver results, as expected.

Idle Interference on VS1838B
Idle Interference on VS1838B

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