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….
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.