diff --git a/light8/io.py b/light8/io.py
--- a/light8/io.py
+++ b/light8/io.py
@@ -1,3 +1,4 @@
+
 
 class BaseIO:
     def __init__(self):
@@ -76,6 +77,9 @@ class SerialPots(BaseIO):
         # this is for a chip with A0,A1,A2 lines all low:
         port = 72
 
+        from fcntl import *
+
+        I2C_SLAVE = 0x0703  #/* Change slave address                 */
         ioctl(self.f,I2C_SLAVE,port)
         self.dummy=0