This post is the second in a two-part series about Reverse Engineering AC Infrared protocols. This time we look at the Mitsubishi Air Conditioner IR Protocol. The project was undertaken by two of our users in France (Vincent & Mathieu), with the help of AnalysIR, who collaborated to reverse engineer this Mitsubishi and previously the Panasonic AC Infrared protocol, both examples of the more challenging AC Infrared protocols. Not only did they identify the individual field codes & checksum but also provided some impressive documentation. Detailed information is available via GitHub which is linked below. This 288 data bit Mitsubishi AC Infrared protocol is composed of two consecutive frames. Both frames are always identical for each signal sent. In common with most AC units the complete settings are 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.
Anyone who has tried controlling an Air Conditioner unit using an Arduino, USB IR Toy, RPi or any MCU will know how difficult it can be to record the longer infrared signals they use. Typical TV systems use IR signals circa 32 bits long, while this Chigo AC unit uses a signal with 197 marks & spaces (or 97 data bits). One of our users, Sertunc – from Istanbul in Turkey, reported his success using AnalysIR to easily record the signal timings for his AC unit and sent us the details along with some nice photos. After testing the validity of the recorded signals using an Arduino, he then set about loading the signals onto his Samsung smart phone (models S4, s4 mini, S5 and more supported). This was helped by installing the free ‘Samsung IR – Universal Remote‘ app onto his phone via Google Play.
We have been intending to add support for LIRC into AnalysIR for a long time. Recently one of our enthusiastic users, working on his Raspberry PI, needed some help getting Air conditioner signals from his ‘Air Conditioner’ infrared remote control decoded. His preference was for a LIRC based approach as he already had this working for his TV via his RPi using a cool web based interface from his smart phone.
We are working on a project to create a custom TV remote to control a SKY+ satellite box, for a friend who cannot manage the standard remote control or even the accessibility ones that are available.