Connection between nodemcu and raspberry in different networks

Question

You can send measured data from a sensor connected to the NodeMCU to the Raspberry, only I don't want a physical connection, I want to connect via another wifi.

Example, Raspberry is at my house and Node in another city, would I have to send Node data to Rasp?

Answer 1

There are generally two common practices:

1. Get a static IP/domain and make the raspberry appear as a server, so it "can be found on the internet". Then make the nodeMCU connect to this server and transmit data.
2. Use Hole Punching techniques to avoid that the raspberry PI appears on the internet. In that case you still need a third server to exchange connection data for the first handshake.

Answer 2

A simple way of doing this is to have your NodeMCU write the data to a cloud-based or 3rd-party server, and have the RPi connect to the same server to read it off again. Exactly how depends on how much data you want to send, how often, whether you need the server to store the data or just pass it on, or if you have particular requirements like security or latency.

One option might be to use Google Sheets to hold the data. Another would be to use a public MQTT broker - MQTT is a protocol designed for passing telemetry data. Real-time database services like Firebase or AWS Amplify might be a more powerful possibility, but more complicated to set up.