This circuit serves as an ultra-low power replacement for multiple LED on-off indicators. It also has the advantage of being easy to read in full daylight. With the parts shown, it is possible to display four bits of information.This circuit use three digits and 2 decimal points for a total of 23 segments. Different groupings of segments can be used for the four indicators.source

This is a low power voltmeter circuit that can be used with alternative energy systems that run on 12 and 24 volt batteries. The voltmeter is an expanded scale type that indicates small voltage steps over the 10 to 16 volt range for 12 volt batteries and over the 22 to 32 volt range for 24 volt batteries. Power consumption can be as low as 14mw when operated from 12V and 160mw when operated from 24V.It is possible to set the meter to read equal steps across a variety of upper and lower voltages.source

Strangeness of this clock is in its expression of numbers, which is realized using seven Leds. Leds are located inside a pipe, one above another and if we move Leds enough fast left or right, we have a space where we can write numbers, characters or anything else. source

If you are developing applications for the PIC, and miss the costly debugging tools, or can’t afford a parallel LCD interface in your design, this serial interface can help printing debug messages and/or reduce the pin count. This version uses a Hitachi HD44780 compatible LCD module in 4-bit mode. The interface is based on the idea of Myke Predko.source

This is Propeller Clock.A motor spins the “propeller”, and a small microprocessor keeps track of time and changes the pattern on seven LEDs with exact timing to simulate a 7 by 30 array of LEDs. It is an illusion, but it works nicely.source