The NodeMCU is an amazing piece of kit. I'd say it's the future for DIY "internet of things". I mean, a microcontroller with GPIO, spi, i2c etc. and built-in wifi hardware, running Lua, for $9. You can throw together "small screen showing live information from the internet" or "sensor uploading data to internet" for less than $20 total cost. The ecosystem is still very new, but it's growing really fast.