Controlling Extra Motors

Tuesday, February 6th, 2007

The little electronic circuit in the picture allows the NXT to control two extra motors. The circuit is connected to one of the sensor ports of the NXT, leaving the three motor ports on the next available. Like the NXT itself, this motor controller can power both the NXT servo motors and other 9V Lego motors (using converter cables). The controller allows the NXT to turn the motors on and off, in both direction, but it does not provide speed control in hardware and it does not use the feedback from the NXT’s servo motors. With this circuit, the NXT can control up to five motors. But its batteries do not have enough power for five motors. Also, the sensor ports do not have enough power for even one motor. Therefore, a separate 9v battery box provides power to the extra motors.

It is essentially home made and it is certainly hand made. It may look semi-professional because it was constructed on a printed-circuit board, but it is possible to build it without a printed-circuit board.
See the full report for details.

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