Button
it will be able to sense modern and will light up and make sound based on it
Go to maker case.com and copy the dimensions to what is shown in photo then cut holes for sensors and then cut
Grab your ultrasonic sensor and plug in wires as shown and then grab the argrino and plug in wires
Tape the sensors into the holes and then wire them into the argino as shown
once connected use it and test Wirth computer too see if lights up
Put the mini bred bored in and plug iun wires as shown in photo after plugging in and then wire it to all of the other ones in the box