The flexibility of the Arduino platform means that it's a great tool to reach for in a pinch, as Martin Raynsford proved recently. Having left his son's Gro Clock - a visual alarm clock for children which uses colours to indicate when it's time to wake up - at a relative's and having found his son struggling to sleep without it, Martin knocked together an open hardware alternative based around an Arduino, an Adafruit NeoPixel ring and a real-time clock module. Like its commercial equivalent, the 'Sunshine Alarm Clock' acts as a dim blue night-light before triggering a 'sunrise' animation across the ring when it's time to get up. With all the hardware in use having been lying around Martin's workbench, it's a great example of the maker ethic.
I rummaged round the garage, found some parts I knew were out there and knocked together this arduino based version of the same clock. Being Arduino relied on the existing libraries to write the code quickly.