[TomTheGeek] built a LEGO tank with a PicAxe controller. Locomotion is supplied by a Lego Power Function motor controller. He cut an LPF extension wire in half so that he could patch into the PWM ...
Maybe you didn’t want your kid to play with toy guns or toy soldiers, so you gave him some wholesome, creative Lego bricks. Which works until he uses the interlocking plastic pieces to make a tank.