Sparkfun 4-digit 7-segment LED Digital Clock using Electric Imp: A very cool little WiFi-based clock that gets it's time from the Internet.
Parts list consists of Sparkfun Electric Imp Breakout Board (BOB-11400), Electric Imp (WRL-11395), and any one of the following Sparkfun color 7-Segment 4-Digit serial LED displays:
A 5V USB Wall Charger (TOL-11456) and Sparkfun USB Type-A to Mini-B Cable (CAB-11301) powers the entire setup (breakout power jumper in the USB position).
Only three wires are used to connect the Electric Imp Breakout to the LED Display:
1. GND (BLK) from the breakout to GND (-) on the display
2. VIN (RED) from the breakout to VCC on the display
3. PIN1 (TX) from the breakout to RX on the display
Running the LED display from VIN (+5V) results in a slightly brighter display; for a dimmer LED display the 3V3 (+3.3V) pin can be used. Software commands are also available to adjust the brightness of the LED display; see the Sparkfun data sheet for more information.
Imp source code is below: