I decided that I wanted to try and use my micro bit as a receiver for a remote control device like a car. My idea was to use one microbit as a receiver and one as a transmitter and have them communicate with the radio function. I also made them display the command they were executing at any time with an arrow. The idea was that the if A and B were pressed at the same time on the transmitter microbit, the signal would be set to forward. This would then output a voltage across both pin 0 and pin 1. If A was pressed, the voltage would only go to 0 and if only B was pressed only to pin 1. This means that you could get the reciever to output a voltage and control two motors basically acting like tank steering  by powering one set of wheels to turn.

My initial plan was to use the output from the microbit to directly power a motor on each side of this car. In order to determine how much power a small motor i found needed, I set up an experiment where the motor was connected to a variable power supply and an ammeter (multimeter in this case).  I increased  the  voltage  in  increments  of  0.1  volts  from  0 to  3 volts.

From 0 volts to 0.3 volts, the motor did not move at all. Therefore, I require at least 0.3 volts output from the pin to make the car move. In reality I will need more voltage than that because this experiment tests how much voltage is required with no load on the motor: the motor is free spinning. I tried putting my finger on the motor shaft to simulate it having to push something forward and at these lower voltages (0.3v to 0.6v) it stopped easily. I then compared these values to the maximum output of the microbit pins.

The maximum rated current for each of the output pins was 5mA which is not nearly enough to power a motor like the one I was testing. I did some research into how others had used the microbit to control motor like the one I had. I found a few videos similar to the one below and all of them involved using an expansion board for the microbit or a separate driver board for a motor.