For those wondering about the several picture toots tagged as #Datenzwerg , which I just boosted:
These are little micro-controllers with a variety of sensors & a battery+USB power supply, all contained in a 3-D printed DatenZwerg (Data Gnome).
Sensors, include temperature, humidity, light, sound pressure, CO2, etc., and the DatenZwerge wirelessly transmit the collected data back to the mobile DZOC (Daten-Zwerge Operations Center).
An app allows conference attendees to view the data from the various DatenZwerge.
I've remotely followed the development, testing & various "deployments", mostly in Germany & surrounding countries, over the past few years.
I hope that these brighten your day & perhaps inspire someone to try similar projects!
8- )