Update README.md

Author: TimeWaster

README.md

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 # Slave-Nixie-Clock
-Software to control a "GRA & AFCH" NCM107 Nixie clock via a serial connection
+Software to control a "GRA & AFCH" NCM107 + NCT412 Nixie clock via a serial connection
+
+!["GRA & AFCH" NCM107 + NCT412](https://github.com/SebiTimeWaster/Slave-Nixie-Clock/blob/master/NixieClock.jpg)
+
+## What it does
+This is an Arduino sketch to control a "GRA & AFCH" NCM107 + NCT412 Nixie clock via serial protocol, basically turning it into a computer display (While ignoring the RTC functionality).
+
+#### One can send two different strings via serial connection to the clock:
+
+##### A 14 byte long display string terminated with a newline:
+
+ * char 0-5:   What to display on the nixies, anything else than a number (isDigit()) shows nothing.
+ * char 6:     "1" to light the upper dots
+ * char 7:     "1" to light the lower dots
+ * char 8-9:   A hex value from 00 to FF representing the brightness of the red led's
+ * char 10-11: A hex value from 00 to FF representing the brightness of the green led's
+ * char 12-13: A hex value from 00 to FF representing the brightness of the blue led's
+ 
+##### And a 2 byte long color cycling string terminated with a newline:
+
+ * char 0-1: A hex value from 00 to FF representing the speed of a LED color cycling animation between 133 and 0.52 seconds long
+ 
+The color cycling animation overwrites the led color set by the display string.
+
+## Installation
+Download a release or clone this project with git. 
+
+## Usage
+Open "Slave_Nixie_Clock/Slave_Nixie_Clock.ino" in your Arduino IDE of choice and upload it to your clock.
+
+For more information see: [afch/NixieClock](https://github.com/afch/NixieClock)
+
+## Changelog
+Changelog v0.1:
+* Initial checkin