Adding WiFi Remote Control To Home Electronics? Be Prepared To Troubleshoot

January 19, 2022 by Donald Papp 32 Comments

[Alex] recently gave a Marantz audio amplifier the ability to be remotely-controlled via WiFi by interfacing an ESP32 board to a handy port, but the process highlights how interfacing to existing hardware often runs into little, unforeseeable problems that can sink the project unless solved.

At its core, the project uses an ESP32 and the ESPAsyncWebServer project to create a handy web interface that is accessible over WiFi. Then, to actually control the amplifier, [Alex] decoded the IR-based remote signals by watching the unit’s REMOTE ports, which are intended as a pass-through and repeater for IR signals to other Marantz units. This functionality can be exploited; by sending the right signals to the REMOTE IN port, the unit can be controlled by the ESP32. With the ESP32 itself accessible by just about any WiFi device, [Alex] gains the freedom to control his amplifier with much greater flexibility than just the IR remote would offer.

Sounds fairly straightforward, but as usual when interfacing to an existing piece of electronics, there were a few glitches. The first was that high and inconsistent latency (from 10 ms to 100 ms) made controlling the amplifier a sometimes frustrating experience, but that was solved by disabling power saving on the WiFi interface. Another issue was that sending signals by connecting a GPIO pin to the REMOTE IN port of the amplifier worked, but had the side effect of causing the amplifier to no longer listen to the IR remote. Apparently, current flowing from the REMOTE port to the ESP32’s GPIO pin was to blame, because adding a diode in between fixed the problem.

The GitHub repository holds the design files and code. This kind of project can be pretty complex, because the existing hardware doesn’t always play nice, and useful boards like a modern ESP32 aren’t always available. Adding a wireless interface to vintage audio equipment has in the past involved etching circuit boards and considerably more parts.

An OSHW IR Remote Control Powered By The ATtiny13A

July 2, 2021 by Tom Nardi 15 Comments

The new hotness in consumer electronics might be RF remotes based on protocols like Bluetooth Low Energy, but there’s still plenty of life left in the classic infrared remote. Especially with projects like TinyRemoteXL from [Stefan Wagner], which let you build and program an IR “clicker” of your own. Whether you want to spin up your own custom universal remote or create a beefed up version of the TV-B-Gone, this open source effort is a great place to start.

As you might have guessed from the name, this project is actually a larger version of the TinyRemote that [Stefan] put together previously. The documentation for that project goes a bit more into the nuts and bolts of talking IR, and is definitely worth a read if you’re into the low level stuff. For the original five button TinyRemote, the hardware consists of little more than a ATtiny13A microcontroller, a pair of IR LEDs, and the transistors to drive them.

But on the XL, things are a bit trickier as there are now twelve buttons for the ATtiny13A to read. Obviously there aren’t enough pins to read so many buttons directly, but with a combination of BAS16TW diode arrays and resistors, [Stefan] is able to detect what button was pressed using the chip’s interrupt pin and ADC. Certainly a handy trick to have in the back of your mind, and the open source nature of this project gives you a great chance to see how it’s implemented.

Between this project and the impressive development board [Djordje Mandic] released recently, it seems we’re looking at something of an infrared hacking revival. Earlier this year we even saw the commercial release of an IR-equipped ESP8266 board.

Digispark Spoofs IR To Get Speakers Under Control

November 24, 2020 by Tom Nardi 12 Comments

The Microlab 6C are a pretty nice pair of speakers, but [Michał Słomkowski] wasn’t too thrilled with the 8 watts they consume when on standby. The easy fix is to just unplug them when they aren’t in use, but unfortunately the digital controls on the front panel mean he’s got to turn them on, select the correct input, and turn the volume up to the appropriate level every time they’re plugged back in. Surely there must be a better way.

His solution was to use a Digispark to fire off the appropriate IR remote codes so they’d automatically be put back into a usable configuration. But rather than putting an IR LED on one of the GPIO pins, he simply spliced it into the wire leading back from the speaker’s IR receiver. All his code needs to do is generate the appropriate pulses on the line, and the speaker’s electronics think its a signal coming in from the remote.

Distinctive patterns on the IR sensor wires.

Power for the Digispark is pulled from the speaker itself, so it turns on once [Michał] plugs them back in. The code waits five seconds to make sure the hardware has had time to start up, then proceeds with the “Power On”, “Change Input”, and “Volume Up” commands with a few seconds in between each for good measure.

Not only was it easier to skip the IR and inject the signals directly, but it also made for a cleaner installation. Since the microcontroller doesn’t need line of sight to the IR receiver, [Michał] was able to hide it inside the speaker’s enclosure. From the outside, the modification is completely invisible.

We’ve seen similar code injection tricks used before, and it’s definitely one of those techniques you should file away mentally for future reference. Even though more and more modern devices are embracing WiFi and Bluetooth control, the old school IR remote doesn’t seem like it’s going away anytime soon.

Replace Your IR Remote With A Web Browser

October 28, 2020 by Tom Nardi 22 Comments

While more and more consumer products are rushing to include WiFi and Bluetooth connectivity, the simplicity and reliability of infrared has kept it in the game in the game far longer than many might have thought. Despite being thinner and sleeker, the IR remote control that comes with your brand new smart TV isn’t fundamentally different than what we were using in the 1980s.

But that doesn’t mean IR devices can’t enjoy some modern conveniences. Sick of misplacing his remote, [Sasa Karanovic] decided to come up with a way he could emulate it to control his TV over the network. Now with nothing more exotic than a web browser on his phone or computer, he can tap away at a visual representation of a remote to control the TV from anywhere in the house. As you might expect, this project could readily be adapted to control whatever IR gadget you might have in mind.

Assembling a simple IR transmitter dongle.

Admittedly, this isn’t exactly breaking any new ground. We’ve seen plenty of people come up with similar IR gateways in the past with varying levels of complexity. But what we really like about this project is that not only has [Sasa] shared the source code that turns an ESP32 into a network-controlled IR transmitter, but he’s put together a concise video that demonstrates how easy it is so spin up your own version. The 3D printed enclosure that looks like a traditional IR remote was a nice touch too.

The hardware for this project is little more than an ESP32 development board and an LED, but if you’re looking for something a bit more built for purpose, we recently saw a very slick open hardware IR gateway that might fit your needs.

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Making A Robot Cleaner Even Smarter

October 20, 2019 by Sharon Lin 9 Comments

Some electric cleaners are effective and some hardly even seem to make a difference. The ILIFE V7s may be a robot cleaner, but even with its cleaning modes and anti-collision system, it still requires IR signals to complete any tasks. Tired of having to be physically in the same place as his robot cleaner, [pimuzzo] decided to take matters into his own hands and build a RESTful remote control to send IR signals from afar.

The program uses the ESP8266WebServer and IRremoteESP8266 libraries for handling HTTP requests and sending and receiving infrared signals. The remote also respond to Actions on Google for controlling the robot over a Google Assistant.

The IR signals are a bit funky – as one user highlighted, finding the IR protocol is a nontrivial task that can be accomplished by recording the IR signals from the original remote with a IR receiver and matching the marks, spaces, and carrier frequency with those of known protocol codes. [Oitzu] was able to match the timing to the NEC 32 bit protocol and find the exact codes on an oscilloscope, which simplified the translation of the codes for the remote.

Sometimes when life gives you a robot cleaner, it’s your job to make it smarter.

Simple Arduino Universal Remote Control

June 4, 2019 by Tom Nardi 11 Comments

The infrared remote control might not hold the seat of honor in the average home theater setup that it once enjoyed, but it’s not quite out to pasture yet. After all, what are you going to use to stop Netflix once the Chromecast invariably disconnects from your phone? As long as there are devices out there that will respond to commands blasted their way via an IR LED, hackers will be looking to get in on the action.

In an effort to make IR remote hacking just a bit easier, [sjm4306] has submitted his Remoteduino for the 2019 Hackaday Prize. With this handy tool in your arsenal, you can focus on developing the software side of your next IR remote project without worry about the hardware. Just upload your code, and get clicking.

As you might imagine, the design is rather simple. On the front edge of the PCB you’ve got the prerequisite IR LED, and a healthy supply of tactile buttons that your code can use as input. The remote features a fairly standard layout on the top half, complete with silkscreened labels for the common functions, but below that [sjm4306] has packed in six general purpose buttons that can be used for whatever you like.

The Remoteduino is powered by an ATmega328P, and the whole thing runs on a CR2032 cell mounted on the backside. [sjm4306] mentions in his write-up on Hackaday.io that battery life was always a consideration during development of the Remoteduino, so he’s made a few energy-saving considerations. Using the internal 8 MHz oscillator instead of an external crystal shaved a bit off the top, and the aggressive sleep routines got him the rest of the way. In testing, he estimates the battery should last a few years even with daily use.

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Air Conditioner Remote Reverse Engineered Despite Esoteric Protocol

August 25, 2018 by Jenny List 23 Comments

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.