Reverse engineering the Mitsubishi AC Infrared protocol

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.

Mitsubishi AC AnalysIR Screenshot
Mitsubishi AC AnalysIR Screenshot

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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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AnalysIR supports PSOC 4 from Cypress

AnalysIR now provides support for the PSOC 4 Prototyping kit from Cypress. Effective immediately users of AnalysIR can use the kit to act as an Infrared source for AnalysIR. The PSOC 4 Prototyping kits are available from Cypress and via their global distributors for just US$4 plus shipping. To use the kit with AnalysIR you will also need an IR Receiver and an optional IR Learner, which can also be purchased with AnalysIR. Initially, the PSOC Firmware is available on request and will be included as part of the installation package in a future release.

PSOC4 and AnalysIR
PSOC4 and AnalysIR

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Preview: DetectIR, advanced infrared receiver

The fourth member of our MakeIR series of devices & kits will be DetectIR. This infrared receiver module can be configured for Visual IR signal detection, Serial over IR or as an Infrared receiver which can handle even the longest Air conditioner signals. DetectIR is built with only the highest quality IR components available.

DetectIR block diagram
DetectIR block diagram

We have provided a link below to the preliminary product data sheet and would welcome feedback on additional, nice to have or missing features, if any. Please read the datasheet for a more detailed description of DetectIR. Continue reading Preview: DetectIR, advanced infrared receiver

Preview: RepeatIR, advanced infrared repeater

The third member of our MakeIR series of devices & kits will be RepeatIR. This infrared repeater module boasts several unique features not readility available to date and is built with only the highest quality IR components available.

RepeatIR block diagram
RepeatIR block diagram

We have provided a link below to the preliminary product data sheet and would welcome feedback on additional, nice to have or missing features, if any. Please read the datasheet for a more detailed description of RepeatIR. Continue reading Preview: RepeatIR, advanced infrared repeater

Preview: SendIR, advanced infrared emitter

The second member of our MakeIR series of devices & kits will be SendIR. This infrared emitter module boasts several unique features not readility available to date and is built with only the highest quality IR components available.

SendIR block diagram
SendIR block diagram

We have provided a link below to the preliminary product data sheet and would welcome feedback on additional, nice to have or missing features, if any. Please read the datasheet for a more detailed description of SendIR. Continue reading Preview: SendIR, advanced infrared emitter

Preview: LearnIR, advanced infrared learner device

The first new member of our MakeIR series of devices & kits will be LearnIR. This infrared learner packs lots of functionality for such a small device, several IR innovations and is built with only the highest quality IR components available.

LearnIR block diagram
LearnIR block diagram

We have provided a link below to the preliminary product data sheet and would welcome feedback on additional, nice to have or missing features, if any. Please read the datasheet for a more detailed description of LearnIR. Continue reading Preview: LearnIR, advanced infrared learner device

Driving an Infrared Led directly from an Arduino Pin

logobutton200x200A common question asked on forums is one about – Driving an Infrared Led directly from an Arduino pin.  Although the answer may be obvious to anyone with at least a basic knowledge of Ohm’s Law, many are confused about how to choose a resistor value for optimum performance. Often, there is a debate about whether a resistor is required at all, given that the AVR pins are rated to deliver an absolute maximum of 40mA on a pin. (Note: All of the quoted specs in the data sheet are for test conditions of up to 20mA on a pin). Of course there are better ways to drive an IR LED with a transistor circuit or even a constant current circuit. However, in this post we consider only the direct drive circuit using a current limiting resistor, as illustrated in the diagram down below.
Make sure to read the caveats at the end of this post.

Analysis of Voltage & Current for Infrared Led driven by Arduino
Analysis of Voltage & Current for Infrared Led driven by Arduino

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Video: AnalysIR Demo Batch Infrared Decoding

Here we show a screen capture demonstration of the ‘Batch Decoding’ feature of AnalysIR. We show Infrared signals from 4 different Air Conditioners and how we can load them into AnalysIR and execute a batch decode of all of the signals in one easy step. Included are signals from Panasonic, Vestel, Fujitsu & Daikin

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