Connect the Arduino outputs with 5 volt power to the relay coils. Use a separate 9 or 12 volt battery for powering the motor. Connect the 9 or 12 volt power to the relay contacts and the motor. Be sure to avoid connecting the 9 or 12 volt power to any of the Arduino input or output pins.
Write an Arduino sketch to run the elevator up and down in the center of the “hoistway” for a fixed length of time in each direction. Note the difference of speed in each direction due to the weight of the car. Account for that in your sketch and get the car to move up and down one floor in each direction.
Team two should build an H-bridge control circuit for one of the elevator drive motors.
Connect the Arduino 5 VDC to Vss (Pin 9) and enable A (pin 6) on the L298. Connect the Arduino output pins to the H-bridge inputs 1 and 2. Use a separate 9 -12 volt battery for powering the motor. Connect the 9 -12 volt power to the H-bridge Vs (Pin 4) and the ground to Pins 1 and 8. Connect the Arduino and motor power grounds together. The H-bridge isolates the logic voltage from the motor voltage. Be sure to avoid connecting the 9 -12 volt power to any of the Arduino input or output pins.
Read more: Arduino Relay Motor Control Circuit