Inspiration
The idea is inspired on a 7 segment display clock near my bed that used only one colour. I wanted a clock that would gradually change colour based on the time. Facing the available standard products, I began to realize I had to make the suitable digits myself. The current products on the market, are the following:

Standard 7 segment display
The well-known classic 7-segment display –
One pre-set colour –
Limited variety of colours –
10 wires on the back –
Relatively cheap, around €0,80 per display –

Adafruit RGB 7 segment display
Although the display looks quite good and offers the – different colours, it has quite some disadvantages –
– High price, around €12 per display –
– 25 pins on the back –
These digits require a lot of solder work. If you want to have a simple 4 digit clock, you would have to solder 100 wires. Also, a more advanced micro controller is needed, since the Arduino UNO doesn’t have enough ports for even one of these digits!

How RGBDigit works

The new developed RBGDigit gives a solution with the struggles that are shown above. We offer the following features:

– Arduino Neopixcel driven
– Neopixels, allowing 16.581.375 possible colours and the use of the well-developed Neopixel library
see adafruit.com/neopixeluberguide/arduino-library
– By using standard neopixels the RGBDigit’s can also be controlled by micro controllers other than the Arduino UNO e.g. raspberry pi.
– Minimum number of connecting pins, using only 3pens in from your micro controller and 3 pens out that are used to connect the digits with each other. 
– Cascading up to 10 RGDigits, using only 3 input wires for all the digits.
– Open source product.
– Currently there is already a RGBDigit library available written by a RGBDigit user .
– Supporting products available for using the
RGBDigit’s.
– At this moment there is a Arduino UNO shield and a Arduino Micro 4 or 6 digit backbone available.
Hardware and demo software available via the Site or Webshop.
– See RGBDigit.com/Download and RGBDigit.com/shop or the Source information section below

Target group
Although the first intention of the digit was to serve my own project, I propose the following target groups for RGBDigits:
Arduino community
Electronics hobbyists
Product Designers
Professional industries
Retro clock fanatics

RGBDigit application proposal
Easily showing a range using colours for
– Temperature
– Speed
– Pressure
– Height
– Humidity

Or as display for
– Fuel indicator
– (Mood) clock
– Countdown timer
– Scoreboard
– Chess clock
– Elevator floor indicator
– Simple news ticker
– Panel meter’s 

Source information

https://www.rgbdigit.com
http://www.rgbdigit.com/rgbdigit/download-page

https://rgbdigit.com/RGBDigit_datasheet.pdf
https://www.adafruit.com/products/1399
https://github.com/ralphcrutzen/RGBDigit

https://rgbdigit.com/description_Clock_ENG