Getting external data to the Arduino
How do people generally get data onto the Arduino, I found a lot of conflicting information online.


There are various ways depending on what the data is and how you access it.


  Does this thing have Wifi or Bluetooth??


Not unless you add WiFi or Bluetooth to it, no.


  I have a raspberry pi spare, can I just use that, sending data from pins?


Yes, there are ways.



How you go about getting data on to an Arduino depends very much on how the data is accessed.  It is possible to add a WiFi interface to an Arduino, either through an official WiFi shield or through adding something like an ESP8266 on a breakout board (ESP-01 is popular) although interacting with the ESP8266 can be tricky.

You can do the same with Bluetooth or any number of other wireless protocols.

The simplest method of getting data to the Arduino, though, is through the USB serial port. Since you have a Raspberry Pi available the most logical option would be to plug the Arduino directly into the Pi's USB port. The Pi can then communicate through /dev/ttyACM0 (or /dev/ttyUSB0 for some clones) and the Arduino receive the data through the Serial object. Exactly how you arrange all that is entirely up to you.