15. Multiple Sensors with Serial

This lesson uses: Arduino UNO R3 board, TinkerBlock TK08 Rotary Potentiometer module, TinkerBlock TK04 Push Button module, TinkerBlock TK01 XL LED module, jumper wires (or breadboard). Review: combine potentiometer and button; outcome: serial shows potentiometer value and button state (pressed/released) at the same time, and the button still controls the LED.

1. Wiring

• TK08 Potentiometer: GND → GND, VCC → 5V, SIGNAL → A0
• TK04 Button: VCC → 5V, GND → GND, SIGNAL → D2
• TK01 LED: GND → GND, SIGNAL → D13

2. New sketch

1. Arduino IDE: File → New (or Ctrl/Cmd + N) to create a blank sketch
2. Confirm board and port are selected (same as Lesson 01)
3. Type the code below into the default setup() and loop() yourself

3. Program structure

Same as last lesson: two fixed blocks setup() and loop().

• setup(): Tell the board “A0 for potentiometer, D2 for button, D13 for LED”; start serial; runs once.
• loop(): Keep repeating “read potentiometer → read button → print both to serial → control LED by button → short delay”.

One piece of code reads both potentiometer and button; both values appear on the serial—upload and see.

4. Code to write

Type the code below line by line into setup() and loop() (do not copy-paste; typing it yourself helps you remember):

#define POT_PIN A0      // Potentiometer on A0
#define BUTTON_PIN 2    // Button on D2
#define LED_PIN 13      // LED on D13

void setup() {
  pinMode(POT_PIN, INPUT);     // A0 input for potentiometer (analog doesn't need pinMode, but OK to write)
  pinMode(BUTTON_PIN, INPUT);  // D2 input for button
  pinMode(LED_PIN, OUTPUT);    // D13 output for LED
  
  Serial.begin(9600);   // Start serial, baud 9600
  Serial.println("Multiple sensors program started");
}

void loop() {
  int potVal = analogRead(POT_PIN);           // Read potentiometer, store in potVal
  int buttonState = digitalRead(BUTTON_PIN);  // Read button, store in buttonState
  
  // Print both to serial
  Serial.print("Pot: ");
  Serial.print(potVal);
  Serial.print(" | Button: ");
  if (buttonState == HIGH) {
    Serial.println("Pressed");
  } else {
    Serial.println("Released");
  }
  
  // Control LED by button
  if (buttonState == HIGH) {
    digitalWrite(LED_PIN, HIGH);   // Pressed: LED on
  } else {
    digitalWrite(LED_PIN, LOW);    // Released: LED off
  }
  
  delay(200);   // 200 ms
}

Program notes

Overall idea: In the same loop() round, analogRead potentiometer and digitalRead button, store in potVal and buttonState; use Serial to print one line “Pot: xxx | Button: Pressed/Released” and control the LED by button. Review multiple variables and serial combo printing.

5. Hands-on

1. After entering the code, click Verify (✓) to compile
2. Click Upload (→) to upload to the board
3. Open Serial Monitor (Tools → Serial Monitor, baud 9600)
4. Watch the Serial Monitor:
   • Rotate TK08: potentiometer value changes 0–1023
   • Press TK04: button shows "Pressed", TK01 LED on
   • Release: button shows "Released", LED off
5. Operate potentiometer and button together and see both values on serial

Expected result:

Serial monitor shows:

Multiple sensors program started
Pot: 512 | Button: Released
Pot: 523 | Button: Released
Pot: 678 | Button: Pressed
Pot: 890 | Button: Pressed
Pot: 456 | Button: Released
...

Proceed to Lesson 16.

6. Common issues

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