I am new to GPIO programming. I have a OWI-535 Robot Arm (non-USB version). I'd like to replace the controller that comes with it with the RPI3. I'd like to be able to send commands using GPIO pins as if I pressed a button on the controller. Is that possible? What hardware do I need? I know I need a breadboard and some wires to connect the GPIO pins to the breadboard. I tried searching online for a tutorial, but they are all for the USB version of the robot arm.
EDIT: Thank you for the pointers Steve. This is my first time asking a question on Stack Exchange, so excuse my mistakes.
I managed to find the circuit diagram of the controller. It simply closes a circuit to move up or down using a switch. There are 5 switches, one for each motor (I think there are called SPDT switches).
So what I'm hoping to do is to remove the controller, and close or open the circuits to run the motors using the GPIO pins. I am guessing I have to buy a component that works like a SP3T switch but is controlled by the GPIO pins? Maybe that's called a SP3T relay? I am also told I could do this with just 2 transistors for each motor.
I hope this is enough info. Thank you in advance.