What is Physical Computing?

Physical Computing

Building computer systems that interact with the physical world through sensors and actuators.

Microcontroller

A small computer on a single chip that runs one program and controls hardware.

Sensor

A device that detects a physical property such as light, temperature or distance and turns it into an electrical signal.

Actuator

A device that converts an electrical signal into physical movement, light or sound.

Many objects around you already use physical computing. Here is one ordinary morning.

1. 1Alarm clock: A microcontroller reads the time, sounds a buzzer and lights up a display.
2. 2Toothbrush timer: A small chip vibrates the brush every 30 seconds using a motor driver.
3. 3Bus stop display: A microcontroller receives arrival data and updates an LED or e-ink screen.
4. 4Crossing lights: A button press is an input; the traffic-light sequence is the output.

python# Loop forever
while True:
    # Input: read the light level
    light = read_light_sensor()

    # Process: decide if the door is open
    if light > 50:
        door_open = True
    else:
        door_open = False

    # Output: show a warning if open
    if door_open:
        display.show(Image.NO)
        play_tone(880, 200)
    else:
        display.show(Image.YES)

    sleep(500)

This program reads a light sensor, decides whether a door is open, and gives visual and audio feedback.