Arduino quick reference guide
This post was going to be about how I connected my robot to a WiFi network and controlled it wirelessly, but I've been having some issues with getting that to work :-( Since I wanted to make a post anyway, I thought I'd post about a quick reference guide I found instead :-)
I found this decided to print it out and laminate it. It's been really useful - I'm really glad I decided to print it out now. It was originally made by a guy called Mark Liffiton. You can find its Github repository here. The version I have posted here is tweaked very slightly to have colour on the reset button, which the original doesn't have.
Next I'm going to attempt to find a similar sort of thing for the esp8266 (upon which the Wemos D1 R2 is based) API, because I'm constantly having to look up various functions all over the place and it wastes a lot of time :-)
Have you found a handy reference sheet? Post about it in the comments below!