Send WiFi Credentials to IoT Devices Using Sound

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.

To transmit the WiFi credentials, Dobson created a JavaScript web application where a user can enter their SSID and password. It then converts that into a modulated audio file that contains the data. All the IoT device needs to do is listen for that audio and then demodulate the credentials in order to connect to the WiFi network. Best of all, this method could be used to get multiple IoT devices connected simultaneously. Dobson has provided the code for the web app and ESP32 over on his GitHub page, so you can experiment with this now.