Arduino: control it from an Android app with MIT App Inventor
Drive an Arduino over Bluetooth from an Android app you build yourself with MIT App Inventor, no Java, one HC-06 module, two-way control.
Tag
#serial
2 tutorials
ESP32: talk to GPS, GSM, or another MCU over UART2
Wire a GPS, GSM, or second microcontroller to the ESP32 over UART2, with working pins, the TX/RX cross, and non-blocking code that parses what comes back.