diff --git a/raspberry/roberto/Serial.py b/raspberry/roberto/Serial.py
index 9114455..cfa7f5f 100644
--- a/raspberry/roberto/Serial.py
+++ b/raspberry/roberto/Serial.py
@@ -4,6 +4,8 @@ import threading
 import serial
 
 class Serial(object):
+    self._callbacks = dict()
+
     def __init__(self, devicename='/dev/ttyUSB0', baudrate=115200):
         self.devicename = devicename
         self.alive = None
@@ -46,7 +48,16 @@ class Serial(object):
                 data = self.serialport.read(self.serialport.in_waiting or 1)
                 if data:
                     print(data)
+                    command = data[0]
+                    argument = data[2:]
+                    cb = self._callbacks[command]
+                    if cb:
+                        cb(argument)
+                        
         except serial.SerialException:
             pass
             #self.alive = False
             #raise
+
+    def add_callback(cmd, callback):
+        self._callbacks[cmd] = callback