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….
We received our ESP8266 NodeMCU several months ago it has been difficult to find a working example of Hardware PWM to generate crisp Infrared carrier signals. Most posts we have read suggest that there is no PWM readily available on any of the supported platforms. As we have already shown with Arduinos and the Particle Photon we figured it would be possible to use a spare UART pin on the ESP8266 NodeMCU to achieve our goal. After some initial success we encountered some watchdog timeouts/resets and it seemed like the uPWM hack would not be possible on the ESP8266 Node MCU platform. For a few weeks we ‘parked’ the effort and today we decided to try again with all of the latest and updated firmware available from the ESP8266 community via the Arduino IDE. This time we were successful and the ESP8266 NodeMCU Backdoor uPWM Hack for IR signals using works!
A few months ago a new user to AnalysIR, from Canada, asked us to assist in adding ESP8266 NodeMCU Infrared decoding over WiFi into AnalysIR. We set about making some upgrades to AnalysIR for this and in double quick time he had AnalysIR accepting IR signals from the ESP8266 over WiFi. He stressed the ease of use of the support within the Arduino IDE for ESP8266 devices and he wasn’t kidding. This motivated us to go and order an ESP8266 for US$3.60 including shipping from Aliexpress. Just the other day the NodeMCU arrived, presumably delayed somewhat by the extended XMAS holidays & celebrations, in this part of the world. So we set about porting our existing firmware for Arduino & Photon over to the new device.
ESP8266 NodeMCU now joins a growing list of devices supported for use with AnalysIR, including: Continue reading ESP8266 NodeMCU Infrared decoding added to AnalysIR
The final member of our first MakeIR series of devices & kits is the A.IR Shield Photon. This shield works out of the box with AnalysIR and is essentially plug & play, with additional prototyping options. The shield plugs into a (Particle) Photon with headers or pin-compatible clone. Although designed specifically for AnalysIR, users can also upload any sketches that run on the Photon for Infrared remote control projects by customising the included firmware. A.IR Shield Photon is built with only the highest quality IR components available and boasts dual Infrared emitters with configurable IR Power. The supplied firmware supports hardware PWM for sending IR signals.
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 data sheet for a more detailed description of the A.IR Photon shield.