There are two ways to make an ESP32 board interact with a mobile application. First, we can use Wi-Fi and Bluetooth protocols to communicate between a mobile device and an ESP32 board. ESP32 has Bluetooth capability with its Bluetooth Low Energy (BLE) model. BLE is a version of Bluetooth technology that provides the same range with considerably lower power consumption.

If you want to make an ESP32 board interact with mobile devices, the mobile devices should have a BLE model as well. Otherwise, we cannot connect to an ESP32 board from a mobile device.

Wi-Fi is one of the most common protocols that mobile devices have. We will use Wi-Fi to facilitate the interaction of media between the mobile devices and the ESP32 board. We can use existing Wi-Fi, or our own Wi-Fi access point (AP), to control a device – control will be possible just within the ESP32 Wi-Fi coverage, and having the ESP32 board in AP mode means we will not be able to control it from the internet. We can create a Wi-Fi AP on an ESP32 board, so that mobile devices can then join that particular Wi-Fi AP. 

Next, we will build a project to make a mobile device interact with an ESP32 board over Wi-Fi.