Lab01: Analog Output

PWM

The Arduino and other digital microcontrollers generally can’t produce a varying voltage, they can only produce a high voltage or low voltage. Instead, you “fake” an analog voltage by producing a series of voltage pulses at regular intervals, and varying the width of the pulses. This is called pulse width modulation (PWM)

analogWrite(pin, duty);

• 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.

FIlter Circuit — Low-pass filter

A basic low-pass filter consists of a resistor and a capacitor.

*frequency = 1/ (2π resistance * capacitance)

How is DC Motor used?

Servo Motor

https://itp.nyu.edu/physcomp/labs/labs-arduino-digital-and-analog/servo-motor-control-with-an-arduino/

Lab02: Lab: Tone Output Using An Arduino

https://itp.nyu.edu/physcomp/labs/labs-arduino-digital-and-analog/tone-output-using-an-arduino/

Question: sometimes it come out with:

Sketch uses 11908 bytes (4%) of program storage space. Maximum is 262144 bytes. Global variables use 3568 bytes (10%) of dynamic memory, leaving 29200 bytes for local variables. Maximum is 32768 bytes. No device found on cu.usbmodem2101 Failed uploading: uploading error: exit status 1

Question: this didn’t work

void setup() {
  // nothing to do here
  Serial.begin(9600);
}
 
void loop() {
  // get a sensor reading:
  int sensorReading = analogRead(A0);
  // map the results from the sensor reading's range
  // to the desired pitch range:
  float frequency = map(sensorReading, 200, 900, 0, 1000);
  // change the pitch, play for 10 ms:
  tone(8, frequency, 10);
  delay(10);
  Serial.println(sensorReading);
}void setup() {
  // nothing to do here
  Serial.begin(9600);
}
 
void loop() {
  // get a sensor reading:
  int sensorReading = analogRead(A0);
  // map the results from the sensor reading's range
  // to the desired pitch range:
  float frequency = map(sensorReading, 200, 900, 0, 1000);
  // change the pitch, play for 10 ms:
  tone(8, frequency, 10);
  delay(10);
  Serial.println(sensorReading);
}

Solved: map reversed.