In our previous post we showed how to generate stable IR carrier signals using the ESP8266 NodeMCU module. A feature of the original approach was that the output IR signal was inverted and required some additional circuitry to invert it again before transmission. Since the original post we have figured out a method to output a non-inverted or standard IR signal thus removing the need for the additional circuitry. This is achieved by using what turned out to be a very simple setting hidden deep in the ESP8266 UART registers which is covered below. Like all simple solutions it also threw up some other quirks of the ESP8266 NodeMCU, which were eventually overcome with the addition of a simple resistor. The Updated ESP8266 NodeMCU Backdoor uPWM Hack for IR signals is detailed below – including updated source firmware, new circuit diagram and explanation of the ‘quirk’. Read on….
One of the most popular projects involving Infrared remote control, is to use an Arduino to control an Air conditioner (AC) system. However, AC signals are usually very long and take up a lot of SRAM on a standard Arduino. Experienced users will go about reverse engineering the AC protocol to make the sketch fit within the 2K Bytes of SRAM. Many hobbyists will struggle, even with the help of tools like AnalysIR to guide them. In this post we cover sending long AC Signals from Flash with IRremote. IRremote (along with IRLib) is a popular open-source library for sending and receiving IR remote control signals with Arduino. The demo code covered in this sketch extends our previous sendRAW example by demonstrating how to store many long AC signals in Flash with little or no SRAM overhead.
Marco is a volunteer for an organization (NSW Australia) that builds custom aids for people with disability, and has recently been looking at a project to create a ‘very large button’ IR remote control for a cable TV Set Top Box (STB). The custom unit needed basic functions (Channel Up/Down, Volume Up/Down and Power On/Off). Commercially available large button remotes have buttons that are still too small and/or they have too many buttons. Soon he hit a roadblock trying to capture some difficult Foxtel signals and searched all over the web looking for a solution. Needless to say, nothing worked out for him until he came across AnalysIR via Google. Once he started Troubleshooting the Big Button Infrared remote control with AnalysIR the root cause of his problems became obvious.
One of our users from Italy, Guido, was tasked with upgrading an old in-house WRC system to allow the team of Sport’s Journalists to access the rack of satellite receivers relaying the various sports events around the building. The challenge is that all of the STB (Set Top Boxes) are located in a dedicated room away from the Journalist’s desks and it is impractical for them to manually change the stations when working to tight deadlines. Previously there was a system in place to remotely switch feeds, but Guido needed to upgrade the system to handle the ever growing number of devices and Infrared protocols. Luckily, he found AnalysIR during his research to implement ‘a hack for Hacks using AnalysIR‘.
In this blog post we follow up on our recent article about generation of infrared PWM from the Photon’s UART where we suggested that it may be possible to achieve something similar with the Arduino. In our previous attempt the Arduino was only able to generate PWM at 40 kHz and 33 kHz using the same approach. After some investigations we discovered a new approach which provides an even better set of results using the Arduino’s USART. Yes, we were able to generate 30, 33, 36, 38, 40 , 56 and surprisingly the illusive 455 kHz which was not possible on the Photon (using this approach). Read on for the details. Readers should also study our original series of articles on ‘softPWM‘ for a better understanding of the source code which can be downloaded below.
We have just posted a 25 minute LearnIR video tutorial introducing the GUI (Graphical User Interface) of LearnIR, which is available via YouTube. The tutorial covers the important features available with LearnIR through the GUI. We cover each of the feature tabs in the Windows application including Learning, Configuration, Utilities, Library, Debug mode and firmware updating.
Continue reading LearnIR Video Tutorial GUI Introduction
Since we received our Photon several months ago it has been difficult to find a working example of Hardware PWM on the Photon. Initially, we ported our softPWM approach to the Photon, which is excellent. However, we figured it must be possible to use at least one of the spare UARTs on the Photon to achieve our goal. So first we started prototyping on the Arduino and quickly got a working example with some limitations – only 40 kHz and 33 kHz carrier frequencies were possible with the UART without delving into the registers a bit more. Then we moved the code over to the Photon, leveraging our previous softPWM examples, upgraded with the Arduino code – EUREKA! The Backdoor uPWM Hack on Photon for Infrared signals.
We have just launched a short 11 minute AnalysIR video tutorial introducing the use of the Reverse Engineering Tool feature in AnalysIR, which is available via YouTube. The tutorial covers the important points in reverse engineering in infrared signal of a Toshiba Air Conditioner. We focus in on the temperature field and show the process to identify the bits within the signal related to the temperature. Users of AnalysIR can follow this process to reverse engineer their own signals using this powerful tool.
We have just launched a short 6 minute video tutorial for AnalysIR introducing the use of the Checksum Calculator feature in AnalysIR, which is available via YouTube. The tutorial covers the steps to verify the position and type of checksums that are typically found in Air Conditioner infrared signals. The types of checksums covered include:
- …for both bytes and nibbles.
In Part 1 of this series, we demonstrated how to send signals using soft or Simple Infrared PWM on Arduino. In our Part 2 post we looked at sending RAW IR signals – specifically a RAW NEC signal and a longer RAW Mitsubishi Air Conditioner signal using soft PWM. We have since improved the PWM method shown in Part 1 Part 2 to provide better performance and improve portability. In this Part 3, we will take the signals from Part 2 and show how to send them using their binary (or Hex) representation, which can save lots of SRAM in many projects, particularly when dealing with longer AC signals.