The badge that does so many things you can make up your own stuff to do with it.
So what is the KareWare Badge?
It's a heart shaped electronic circuit board with a few electronic components that detect motion from pets/humanoids from about 5 meters or closer. (possibly works on zombies, not guaranteed). One motion is detected, two alert leds are triggered to flash for up to 5 seconds. (tunable)
As long as motion continues the LEDs continues to flash.
This sensor is much smaller than most PIR modules, which makes it great for unobtrusive projects. It's also fully-contained so no programming needed, just add the main components and you're good to go. 
Perfect as a desk gadget to let you know when people are walking up behind you while you're focused on work.
Great to let family know when you're in the middle of a project as a do not disturb sign on your door..
Friendly reminder to B.A. WARE before entering.
The KareWear badge was originally created as a project for folks to KareWear of how close you are standing to others, so you remember to social distance your self when in the middle of a crowd.
If you are vaccinated, it's a great talking piece to let others know that you care, and for others to B.A.WARE that the virus is real, and to do their part for getting vaccinated so we can all return to normal.
The coverage area is approx 130 degrees left to right and 100 degrees up and down.
Optionally, there is a large version of this sensor that can be used to cover additional areas if needed.
Have been involved in teaching IoT, electronics, to kids for the past few years, including local community centers, Meetup groups, MakerFaire events, and we are now about to produce our own kit device.
Order a fully assembled or order the bare board and learn how to source, solder the motion sensor and LED yourself to create your own custom design.