I have a project where I need to use 7 motors and therefore I have to use two NXTs. My understanding is that the only possible way of connecting one NXT to another is to use bluetooth. From testing I have carried out it seems that it is not adequate to control the robot in realtime. For instance if the robot needs to move forward, the NXT 1 is sending a command to NXT 2 to instruct the motors A and B to turn, however it seems that the second command does not arrive immeadiately and motor A will start turning without motor B, causing the robot to drag to one side.
I have also noticed that if an obstacle is detected, the robot is unable to stop both motors immeadiately.
if the avoid behaviour detects an obstacle the NXT 1 sends a a backward command from NXT 1 to NXT 2. If after completing the backward process the robot detects again that there is no obstacle it moves straight forward and so forth. The process itself is very slow and sometimes the robot moves forward whilst an obstacle is being detected but since it is still executing the previous commands it will get out of synch with the real behaviour.
I am sure that there is a solution to these issues. Any ideas how to resolve?