An Arduino controlled Neopixel (WS2812B) LED ring to emulate a TV running thus giving the impression your home is occupied.
Perhaps you're already familiar with a TV Simulator - a gadget that shines light onto a wall, curtain or blind in such a way as to simulate a TV, thus indicating someone is home and that this house is not a good target for opportunistic thieves.
This Arduino-controlled Neopixel (WS2812B) ring does the job splendidly, at a low cost and best of all YOU have control of what the multicolour pattern looks like.
The code here is simple, with lots of randomisation. It demonstrates just how easy it is to use the FastLED library to control each individual LED's colour and brightness - super quick too!
I've installed this in my lounge and taken a look from outside; I could not tell that a real TV was not switched on, but using just a tiny fraction of the power that a proper TV would consume.
The 12-LED 5050 WS2812B ring I'm using here costs less than two British pounds (about $2.60) so you can immediately see how cost effective this could be. Even factoring in the cost of an Arduino Nano, a box to put it all in and a 5v PSU I estimate you could build this for less than a tenner! And the satisfaction in doing so? Priceless!