Hi everyone, I'm a middle schooler and i am in a program called MESA. I need help on how to code and build the circuitry to open and close a claw. We are planning to turn a motor (any motor really) to turn 90 degrees and then reverse I would really really really appreciate it if someone code give me a picture of the circuitry and code, really appreciate it. Thanks in advance
Look at the Servo library and examples. It comes with the IDE.
but does i show me how to do the circuitry
If you dig deeply enough, it does. 
Circuit
Servo motors have three wires: power, ground, and signal. The power wire is typically red, and should be connected to the 5V pin on the Arduino board. The ground wire is typically black or brown and should be connected to a ground pin on the Arduino board. The signal pin is typically yellow, orange or white and should be connected to a digital pin on the Arduino board. Note that servos draw considerable power, so if you need to drive more than one or two, you'll probably need to power them from a separate supply (i.e. not the +5V pin on your Arduino). Be sure to connect the grounds of the Arduino and external power supply together.
Is it better if I use sweep or knob to me sweeps seems like it might be the one
Jakesparrow:
Is it better if I use sweep or knob to me sweeps seems like it might be the one
Try both. They don't cost any money.