Color changing coaster has a built-in drink detector

color-changing-coasters

[Robert] put together his own illuminated coasters that know when they hold a drink. They look fantastic, thanks to professionally produced PCBs and a layered, laser-cut acrylic case. They're much like the pagers given to restaurant-goes who are waiting for tables, but this version is much fancier (and doesn't include the vibrating/paging feature). The RGB-LED board is a previous project which … [Read more...]