We reverse engineer this Mitsubishi AC Infrared protocol, an example of the more challenging AC Infrared protocols.
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. 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.
we decided to put 2 of the more common 38kHz receivers, TSOP34438 vs VS1838B, 'head-to-head'
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' . For more details visit:
A common question asked on forums is one about "Driving an Infrared Led directly from an Arduino pin". Often there is a debate if a resistor is required...
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 of 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, as illustrated in the diagram down below. Make sure to read the caveats at the end of this post.
We have been updating the AnalysIR documentation for the upcoming 1.0 release and realised that AnalysIR now decodes 40 Infrared protocols. Wow!. Along with the most common TV & media remotes controls there are 14 Air Conditioner protocols included. The full set of protocols is included with the latest ‘dev’ release, which is available to all current & new owners of AnalysIR (less the aforementioned documentation) in advance of the pending 1.0 release. The 1.0 release will incorporate over 170 new features, updates and fixes compared to the initial release and also supports our new IR Learner which will be launched along with a range of Infrared kits in the coming months.
Geeky gadgets Arduino Infrared Learning Processor Board Set (video) Geeky gadgets Developers, makers and hobbyists that enjoy making projects using the Arduino platform might be interested in a new Arduino compatible infrared learning processor...
Make your own infrared receiver with two resitors, an IR Led and Arduino
Our recent post about the silver bullet IR receiver proved very popular and we promised that we would follow-up with another variant of the poor maker’s Infrared receiver. This time we are using an IR Led (emitter), 2 resistors and any standard Arduino. You will also need to download the Arduino code provided below, compile and upload it. One of the most common problems encountered when trying to decode IR signals is that makers don’t always have the appropriate IR receiver for the job in hand or have to wait for one to be delivered by mail. Here we present an affordable method to allow you to use any IR emitter (LED) as a receiver and as a bonus we are publishing the Arduino code to make it all work.
A review of timing distortions in Infrared Receivers
Many electronics enthusiasts will be familiar with how Infrared receivers demodulate IR signals. In this post we show a visualisation of the time lag and distortion of the signals as they pass through the IR receiver for demodulation and noise filtering. Most DIY projects use the raw timings from the IR receiver to decode individual signals. However, not many will be aware that IR receivers can distort the signal timings by significant amounts. Fortunately, common IR decoders take this into account and compensate for timing distortions introduced by infrared demodulators / receivers.
Dublin, Ireland – 31st January 2014. We are happy to announce the latest ‘New Year’ release of AnalysIR to all our backers & supporters. Since the completion of the crowd-funding campaign on Indiegogo we have added over 125 updates and enhancements to AnalysIR, with more to come. A major highlight of this release is full …
A major highlight of this release is full AnalysIR support for USB IR Toy from Dangerous Prototypes (V1 & V2 hardware) for decoding and resending IR signals at all common modulation frequencies. In our opinion, AnalysIR is now the premier GUI supporting DP’s IR toy, not to mention the Arduino, RPi, MSP430 F5529 LaunchPad (beta) and more. A selection of enhancements in this latest release, include...................
Two of our users in France collaborated to reverse engineer one of the more challenging Panasonic 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.
Batch Infrared Decoding can speed up signal decoding for imported data sets or when changing decoding tolerances. Currently, AnalysIR supports over 40 Infrared Protocols, but you can analyse 99.99% of protocols with AnalysIR.
Having already replaced standalone cameras for many people, the smartphone also has the humble remote control in its sights. MightyRC is the latest in a line of products looking to reduce remote control clutter in the environment where they have multiplied the most over the years – the living room. It allows all appliances compatible with infrared remotes to be controlled via a single app on a smartphone or tablet.
The MightyRC system is made up of a box measuring 80 x 80 x 18 mm (3.1 x 3.1 x 0.7 in) and a companion smartphone app. Commands are entered in the app and transmitted to the box over Bluetooth 4.0, provided the smartphone is within 100 ft (30 m) range. The box then relays these commands to the various appliances using an infrared transmitter. The company claims the IR transmitter is good to a range of around 6 m (20 ft), and is so powerful that appliances won't necessarily need to be in the box's line of sight – although don't go expecting the infrared beams to travel through walls. The device also has an infrared receiver, which allows it to learn from existing remotes.
Naming each of your devices in the app will allow the MightyRC to differentiate between the them. Further to channeling the controls of these different appliances into the one interface, MightyRC also features a nifty "Activation" function. This feature allows users to program a one-touch control to activate preset functions across different devices. So you could, in theory, setup an activation called "King of Westeros" allowing you to switch on your television, switch the cable box to the correct channel, and turn on the surround sound system with just one click in time for the latest episode of Game of Thrones.
Oscilloscope infrared receiver - using a standard IR Led soldered to a BNC and plugged directly into a spare channel of the Oscilloscope as an IR receiver.
A while ago we came across a website on infrared remote controls which suggested a simple way to view IR signals using an Oscilloscope. The idea is to use a standard IR Led mounted into a BNC/RCA plug using a spare channel making an Oscilloscope infrared receiver. So we set about ordering the connectors, which arrived in the post today. Another way of looking at this device is as a ‘poor-mans’ IR receiver, but if you have an Oscilloscope to plug it into then maybe you are not so poor after all.
Since introducing support into AnalysIR for the USB IR Toy we haven’t played too much with setting the different infrared modulation frequencies. After reading some mixed experiences on the Dangerous Prototypes forum we decided to put it to the test. So to start off we implemented a feature in AnalysIR to set the modulation frequency and to default to 38kHz at start up.
Recently we have been helping several members on the Arduino forum to record and playback their remote control signals from their Air Conditioners.
..... These signals are typically much longer than those of TVs or common media devices. The 2 most popular libraries for Arduino, IRremote & IRlib are excellent, but have some limitations which we have covered in a previous post. In this post we address one particular issue that is proving challenging to users.
Decoding Airconditioner Infrared remote control using AnalysIR, Raspberry Pi & LIRC
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.