Ok i got to play with a OWI robot arm, so i tried to hack it with microbrains.
The arm is driven with 5 dc motors and a light.
It's connected to a digital controller trough a 8pin ribbon cable.
the connections in the ribbon cable are
0 left + vcc
1 base rotate left/right
2 1 segment up/down
3 2 segment up/down
4 3 segment up/down
5 pincer open/close
6 light on/off
7 right + vcc
connecting 1,2,3,4,5,6 to 0 makes the first action; connecting 1,2,3,4,5,6 to 7 does the opposite action.