Problems with microbit and app inventor

[SteveJG]

This tutorial might help

App Inventor, Micro:bit and UART

App Inventor, Micro:bit and UART Somehow, communicating with a micro:bit via UART is more difficult than it should be. For now, using the extensions as indicated in this tutorial, will ensure that everything works. This tutorial is intended to show how to use Bluetooth Low Energy (BLE) to send messages to a micro:bit. This can be used to control a toy robot car or any device that uses a micro:bit as its brain. This first part will only cover the basic communication with a micro:bit via BLE. A…

or

MIT_App_Inventor_Microbit_Temperature.pdf