More buttonreader documentation

Readme.md

@@ -106,6 +106,33 @@ device, baudrate (default 9600), parity (default N) and stop-bits (default 1).
 As with the fifo, an ASCII-number for the player which pressed a button is
 expected. All other characters are ignored.
 
+*BeopardySerial* mimics the protocol used by the Beopary software. It reads
+from a serial device and takes the same arguments as *Serial*, but in addition
+to taking button presses from the serial it also gives feedback about the
+current gamestate.
+
+*Unix* opens up a unix domain socket on your local filesystem, first argument
+being the path to where it should be created. To send a player button press,
+send its ASCII number ('1'-'9' is supported). The board will send a 'O' if
+the buzzers (buttons) are open and a 'C' when they are closed. To indicate
+that it is a player's turn the board will send a "TX", where X is the current
+player's number (e.g. "T3" for player 3).
+
+Examples:
+
+	# use BeopardySerial
+	playerInput:
+	 - Type: BeopardySerial
+	   Args:
+	    - /dev/ttyUSB0
+	    - 19200
+
+	# use a unix domain socket
+	playerInput:
+	 - Type: Unix
+	   Args:
+	    - /tmp/seopardy.sock
+
 Writing an own class for player input should be fairly easy. Within its own
 thread the class can do whatever it wants (including blocking I/O). When it
 wants to signal a button was pressed it just needs to emit a ButtonEvent.