Buy your own Electronic Sandtimers here!
Electronic Sandtimers were available as part of a Kickstarter project. They arrive pre-programmed and ready to use. They are now available for sale through Tindie.
Ensure that the holes for the light are open. Use a heated large paperclip to widen the holes if necessary.
By themselves, the holes do not allow much light through. For the light to really pop and shine, add 1.5mm PMMA cables and trip them flush with the top. These serve as light pipes, funneling the light from the LEDS through the case and allowing the lights to be as bright as without the case.
1.5 PMMA cable is available through eBay or AliExpress, among other places. A very short strand is enough for dozens of cases.
Hacking / Development
More support files are available via the GitHub project page.