added basic requirements to readme

fixed readme

README.md

@@ -8,22 +8,32 @@ LedD is a daemon for interfacing LED stripes written in python3. It provides an
 - an open effects github repository with simple download-and-run system
 - automatic enumeration of the connected controller devices, restart/reset and status querys
 
-### Plugins
+## Requirements
 
-Plugin functionality is planned as we provide APIs for effects and plugins to use. Here are some we are going to provide if they are finished.
+- Python 3.x, tested with Python 3.4
+- Linux with i2c-dev module loaded and permissions to access /dev/i2c-* devices, preferably as non-root (add your user to the i2c group)
+- Compatible controller device connected via i2c; currently supported controllers:
+    - PCA9685
+- __Note__: Plugins can have different permission requirements
 
-- plugins
+### Plugins & Effects
-    - lux sensor (TSL2591) for providing information if lights need to be turned on
+
-    - start/stop hook so you can switch your LED power supply
+Plugin functionality is planned as we provide APIs for effects and plugins to use. Here are some we are going to provide when they are finished.
-    - planned hook points for plugins include
+
-        - start/stop
+Plugins
-        - set color (for e.g. gamma correction)
+- lux sensor (TSL2591) for providing information if lights need to be turned on
-- effects
+- start/stop hook so you can switch your LED power supply
-    - pulse
+- planned hook points for plugins include
-    - fade
+    - start/stop
-    - drop
+    - set color (for e.g. gamma correction)
-    - blink
+- controller support
-    - strobe (as far as possible)
+
+Effects
+- pulse
+- fade
+- drop
+- blink
+- strobe (as far as possible)
     
 #### License