Ultrasonic sensors are distance sensors that use sound waves to detect how far away an object is. They send out high frequency bursts of sound and listen for its echo. They then determine how far away the object is based on how long it takes for the sound to return to the sensor. This variety requires an Arduino library to operate.

NewPing Library https://libraries.io/github/PaulStoffregen/NewPing

#include <NewPing.h>

NewPing mysensor(5, 6, 200);

void setup() {
  Serial.begin(9600);
}

void loop() {
  int pingTime = mysensor.ping();

  int distance = mysensor.ping_in();

  int distance_cm = mysensor.ping_cm();

  Serial.println(distance);
}

Servos are specialized motors that support precise control. Rather than spinning off to oblivion like a motor, servos let the designer specify exactly where they want the object to rotate to. Most common servos allow for 180º of rotation.

#include <Servo.h>
Servo myservo;

void setup() {
  myservo.attach(9);
}

void loop() {
  int val = analogRead(A0);
  val = map(val, 0, 1023, 0, 179);

  myservo.write(val);

  delay(15);
}

As a child, I used to always have my nightlight on. It was a light that could spin when spun. I loved having it on because it made me feel safe and I loved watching the dancing flower patterns be projected onto my ceiling while falling asleep. One idea I have is to project something that reminds me of home. When I think of Home, I think of the Bay Area, CA. I might try and project the golden gate bridge, but try and project it with colors.

Sketch of my automatic crankie. It tells a story of what reminds me of home. It is 18in by 12in box with a wood frame. Inside of the crankie, there is a light that turns on with the switch. When the switch is on, the crankie spins, portraying memories of home and California means to me.

A vintage projector/viewfinder/slides