When I first decided that I wanted to make a custom mobile app to relay data from a BLE device that contained various sensors, I thought it was going to be extremely difficult. It was rather the opposite because there were already a few guides on how to get that accomplished. The best guide that I thought was the most useful was written by an engineer at Bam.tech, Guillaume Piedigrossi.
Piedigrossi’s guide provided me with enough details on the both the hardware and React Native side to get a custom mobile app to communicate with my hardware device via BLE. Although I did not use an Arduino as my hardware device, my pre-built BLE hardware solution functioned similar to what Piedigrossi described in his guide without me having to write any code to my hardware. This guide also takes advantage of a pre-built React Native package called react-native-ble-plx that makes it incredibly easy to incorporate Bluetooth functionalities in your React Native app.
Go try to make your own smart devices and check out his guide on how to create a IoT React Native App with Bluetooth below.