Building the remote
This remote should fit on two mounting boards. Start by splitting the power to two slide dimmers. If you have the Gizmos and Gadgets Kit, you might know that the Bitbot requires you to flip one of the slide dimmers so that the remote is easier to use! Each slide dimmer is then plugged into another splitter. One of the wires from each slide dimmer should go to channels 1 and 3 of the wireless transmitter (it can be either 1 channel or 5, but the 5 is better!) The other wire from the splits go into the double AND. One of these wires should go to an inverter before going to the double AND. Finally, the output of the double AND receives a wire and goes into channel 2 of the wireless transmitter. Look at the image for assistance!
The logic behind the remote
The idea of this logic circuit is that channel 2 will only activate if both wheels are in reverse. In order for the double AND to pass the signal through, it must receive an ON signal from both inputs. The reason we inverted one of them is because of how the car will be built. Since the motors will face in different directions and will be on variable mode, they will move in the same direction if the slide dimmers are on opposite settings. This is why we should flip one of the slide dimmers on the remote so it faces the other way - when we put both slide dimmers forward, the car moves forward. We split the slide dimmers so that they could go to the transmitter and to the double AND. We have to invert the one that will be OFF when the car moves backwards - this means that when the slide dimmer is in the OFF position, the inverter tells the double AND that it's ON. This is how we can activate channel 2!
Building the car
The car can fit on one mounting board if the power bit is attached on the edge. Power up your receiver and attach the motors to channels 1 and 3. This is only possible with the tethered motors, which you can get from the Gizmos and Gadgets Kit. Channel 2 will go to a pulse and a buzzer. Set the pulse to an interval that sounds like a car's backing up horn! Attach your wheels and use a rubber band to attach the ball caster on the bottom of the board (this is a special trick: take the ball out and rubber band the black portion, then put the ball back in!) Finally, use another rubber band to secure your battery. I like rubber bands because they are reusable, easy to move, and totally not sticky! Make sure your motors are on variable mode. Have fun!