Air Conditioner Remote Reverse Engineered Despite Esoteric Protocol

Infra-red remote control is something of a Done Deal when it comes to hardware hacking, it has been comprehensively reverse engineered, and there exist libraries and software packages to seamlessly take care of all its quirks. Just occasionally though, along comes an IR remote whose protocol doesn’t follow that well-worn path

[William Dudley] found himself in this position with an air-conditioning unit remote control. He found it sent a stream of data with all settings of the machine rather than the single command codes you might expect from a familiar TV remote. The solution was to reverse engineer and reimplement the IR codes.

His reverse engineering relied on an Arduino and IR receiver which he used to sniff the packets coming out of the remote. Eventually he was able to recognise some of the functions from the remote, and create his own protocol that can recreate most of the remote’s functions. This was pushed over to a Raspberry Pi Zero which uses an IR LED to command the air conditioner, joining the ranks of his growing home automation setup.

The write-up makes for a fascinating primer on analysis of obscure IR protocols, and is well worth a read for anybody with an interest in the topic. Meanwhile if you want more IR reverse engineering stories, try this tale of a bathroom scale.

Insane Covert IR Illumination

[Onironaut] over at lucidscience sent us a link to his latest project, some IR illumination panels. At first, we were mildly enticed by his usual high standard of photography and description. It was just an array of LEDs though. Still, we kept hitting the “next page” button because he goes into such great detail. Then we saw version two. Instead of simply being an array of IR LEDs mounted outside for his security camera, he has mounted 1536 IR LEDs inside an old flat panel monitor. That’s a fake monitor producing 180 watts of IR light, and we think that’s even at half power!  He replaced the screen of the display with one way mirror, so you would have no idea that it isn’t just a normal screen sitting on his desk.  Great job as usual [Onironaut].

Compound Eyes For Your Robot

In this writeup, you can see how to build a cheap compound eye system for your robot.  Using 4 IR LEDs and 4 phototransistors, [oddbot] gave “Mr General” the ability to follow movement in objects fairly well, assuming that they are within 200 mm. Being IR, it has the typical drawbacks such as sensitivity to light or overly reflective surfaces, but we like the idea. It is perfect for a nocturnal or low light robot.

[via Hacked Gadgets]

Building An IR Receiver For The Popcorn Hour C-200


[Linuxworks] has posted a writeup on how to build an IR module for the popcorn hour c-200. We weren’t familiar with the popcorn hour c-200, so we had to look it up. It seems to be a media center pc sort of thing. We’re not reviewing the unit itself, since we’ve never used one, so we’ll just get back to the mod. The device uses an RF remote, which some people didn’t like as much. Luckily it has an expansion port which can be utilized to get IR signals into the machine. [Linuxworks] has used a cheap IR sensor and a standard headphone plug. He notes that equipment passing power through these plugs should be turned off before plugging them in or removing them as they short momentarily during insertion.

External Keyboard With An IPhone


Using an IR keyboard is now possible with a non jailbroken iPhone. The folks at perceptive development have developed a custom interface that connects through the headphone jack.  They had already developed the serial modem, so this was just another step at connecting peripherals. With some smart and small packaging, this could be a nice attachment to keep around. You can see a video of it in action after the break.

Continue reading “External Keyboard With An IPhone”

IR Controlled Light Dimmer


This is a pretty useful device. It is an IR controlled light dimmer. It goes in line with the main power and controls how much gets through to your light. You can adjust the brightness with a TV remote control. Finally, we can retire our clapper! These are commercially available, but making your own is just so much more fun. You may have to dig a little on their site for the schematics and programming. There are tons of other projects there as well so have fun.  You can see a video of it in action after the break.

Continue reading “IR Controlled Light Dimmer”