In this week's lab, I performed different experiments to control the tone output amplitude & frequency. I also conducted experiments to control the servomotor.

Tone Control with Arduino Nano 33 IoT using Force Sensing Resistor Analog Input through Speaker

I used D8 as analog output and A0 analog input pin. I am using changing resistance from force sensing resistor as the input to change the volume of the speaker output.

Tone control using force sensing resistor through Arduino Nano 33 IoT

Output : Tone control using force sensing resistor through Arduino Nano 33 IoT

int speakerPin = 8;
int sensorValue = 0;      //Analog input from force sensor

void setup() {
  // put your setup code here, to run once:

  Serial.begin(9600);
  pinMode(speakerPin, OUTPUT);
}

void loop() {
  // put your main code here, to run repeatedly:

  //Read analog input for force sensor
  sensorValue = analogRead(A0);

  // play the tone for 1 second:
  tone(speakerPin, 440,1000);
  // do nothing else for the one second you're playing:
  delay(1000);
   
  Serial.println(sensorValue);

}

Tone Control with Arduino Nano 33 IoT using Force Sensing Resistor Analog Input through Speaker with transistor

I used D8, D9 as analog output and A0 analog input pin. I am using changing resistance from force sensing resistor as the input to change the volume of the speaker output. Pin D8 has a speaker connected with resistor & D9 has the speaker connected along with the transistor.

Tone control using force sensing resistor through Arduino Nano 33 IoT with/without transistor alongwith speaker

int speakerPin_tran = 9;
int speakerPin_notran = 8;

int sensorValue = 0;      //Analog input from force sensor

void setup() {
  // put your setup code here, to run once:

  Serial.begin(9600);
  pinMode(speakerPin_tran, OUTPUT);
  pinMode(speakerPin_notran, OUTPUT);

}

void loop() {
  // put your main code here, to run repeatedly:

  //Read analog input for force sensor
  sensorValue = analogRead(A0);

  // play the tone for 1 second:
  tone(speakerPin_tran, 440,1000);
  // do nothing else for the one second you're playing:
  delay(1000);
    tone(speakerPin_notran, 440,1000);
  // do nothing else for the one second you're playing:
  delay(1000);
   
  Serial.println(sensorValue);

}

Questions

I didn't find much difference in the speaker tone output with or without transistor, Why?