Come up with a project.

• Input_Pullup

Analog Output

• Pulse Width Modulation (PWM) - “Fake” an analog voltage by producing a series of voltage pulses at regular intervals, and varying the width of the pulses.
  • Pseudo-analog Voltage - Resulting average voltage

Pin is high is called Pulse width - half the total time it takes to go from low to high to low again.

*Arduino boards have a few pins which can generate a continuous PWM signal. On the Arduino Nano 33 IoT. They’re pins 2, 3, 5, 6, 9, 10, 11, 12, A2, A3, and A5.

• pin refers to the pin you’re going to pulse
• duty is a value from 0 – 255. 0 corresponds to 0 volts, and 255 corresponds to 5 volts. Every change of one point changes the pseudo-analog output voltage by 5/255, or 0.0196 volts.

Applications of Pulse Width Modulation

• LED Dimming - The simplest application of analogWrite()  is to change the brightness of an LED.

• DC Motor Speed Control - the speed of a DC motor using the analogWrite() command as well.

• Servomotors (伺服馬達)- control the movement of something. Motors with a combination of gears and an embedded potentiometer (variable resistor) that allows you to set their position fairly precisely within a 180-degree range.

  • Included three wires:
    • Power (Mostly +5V)
    • Ground
    • Control

• Changing Frequency

  • If want to generate a changing tone on an Arduino microcontroller, however, there is a tone() command that will do this for you:

    1	tone(pin, frequency);

• Ranges of Values