Techie coasters have been popping up everywhere. We've already blogged about coasters themed after circuit boards, floppy disks, pixelated images, Apple compatible icons, vintage records, Polaroids, and iPhone icons. Whew! Now add these hot- and cold-sensing Smart Coasters to the list...
Smart Coasters are plastic coasters with embedded LEDs that light up red when you put a hot drink on top and light up blue with a cold drink. The design is fully analog—no microcontrollers and no programming—and they are powered by a solar cell so that the whole thing is hermetically sealed, making them waterproof and washable.
These aren't for sale. Rather, they're a DIY project from The Hungry Scientist Handbook. Complete step-by-step instructions are available for both the electronics and the resin casting. Full instructions to build your own can be found in The Hungry Scientist Handbook (which runs about $12 at Amazon).
The question now is, do you care enough about the novelty of the coasters to make it yourself. We sure don't see anybody actually needing a little LED to tell them if their drink is hot.