In order for the internet of things to be viable individual connected devices need to be as inexpensive as possible. It’s entirely possible that you’ll end up with dozens of IoT devices in your home, so they need to be affordable. Therefore expensive components like LCDs and keyboards aren’t practical to integrate into individual devices. But, the entire point of an IoT device is that it’s connected to your network, which means you need a way to enter your WiFi credentials. Rob Dobson’s solution transmits those credentials via audio to any IoT device equipped with a microphone.
The microphone itself can be any inexpensive model, which is significantly cheaper than an LCD and keypad. This setup will work with any microcontroller-based IoT device that can sample audio at 8KHz — which is pretty much all of them these days. In the video, Dobson demonstrates this with an ESP32 development board. It’s equipped with a display, but that’s only there to show the status and isn’t actually necessary for this method to work.