added readme file

added basic instructions, how to use this and what it supports

README.md

@@ -1,2 +1,35 @@
 # LinuxCNC_ArduinoConnector
+
++++this is still in early development and is untested, i don't recommend using it in an actual machine+++
 For my CNC Machine i wanted to include more IO's than my Mesa card was offering. This Projekt enables to connect Arduino to LinuxCNC to include as many IO's as you wish.
+
+
+Arduino is handling all the IO's and sends all changes over Serial. It is decoded and integrated in hal with Python-serial.
+
+This protocol is slow compared to other solutions, but easily adaptable and expandable through the Arduino platform.
+
+# Features i have included: 
+(as many Pins as your ARduino provides)
+- analog Inputs
+- latching Potentiometers
+- 1 absolute encoder input
+- digital Inputs
+- digital Outputs
+Right now i am also working on
+- virtual Pins (multiplexed LED's or WS2812)
+
+
+# Installation
+- configure the Firmware file to your demands and flash it to your arduino
+- connect the arduino to your LinuxCNC Computer via USB
+- install python-serial
+- open arduino.py and configure it to match your arduino settings. 
+- also check if the Serial adress is correct for your Arduino
+- move arduino.py to  /usr/bin and make it executable with chmod +x
+
+- add to your hal file: loadusr arduino
+
+
+You can now use arduino pins in your hal file. 
+Pin Names are named arduino.[Pin Type]-[Pin Number]. Example:
+arduino.digital-in-32