RemoteXY is a website that allows you to easily build a phone interface that will talk to your hardware over Bluetooth LE, USB, or Ethernet (including WiFi). One thing of interest: even though the interface builder is Web-based, the service claims that the interface structure stays on the controller. There’s no interaction with the remote servers when operating the user interface so there is no need for an external Internet connection.
The system supports Arduino and ESP controllers. On the phone side, you can use Android or iOS. The RemoteXY site has plenty of examples.
We know there are other ways to do this, including just rolling your own. However, it is nice to have different options and RemoteXY has all the usual controls, including a joystick, a color picker, a level, graphs, and more.
We did our own version of this project using Blynk. We’ve also seen Visuino before, too.
Source: REMOTEXY SIMPLIFIES ARDUINO CONTROL