Demonstration program on how to drive a SIM7020 NB-IoT modem, then set up a dashboard using T-Mobile's network and AllThingsTalk API.

Build a simple MQTT message board with Arduino Ethernet.

Control RGB LED with a slider in simple mobile app. Uses a very, very simple message with TCP connection between Arduino and mobile app.

How to make a simple remote display system with an OLED display and Arduino Ethernet. You can absolutely send your messages via mobile app.