Announce accessibility menu states

Use Serial announcements to identify the selected accessibility setting and verify its current state alongside the OLED.

UX Uma: I want you to compare the announced state with the visible state and name the settings that still lack an equivalent nonvisual description.
Predict the reading, then compare it with the measurement.

Wokwi ESP32

Third party Tool

Use Serial announcements to identify the selected accessibility setting and verify its current state alongside the OLED.

Tier 1 · Web · No account

Version tested: Compiled and booted by the Wokwi gate (ESP32 Arduino core 3.3.11); captured in the Wokwi web editor on 2026-09-09. Date: 2026-09-09.

Open the ESP32 editor, paste diagram.json, then paste sketch.ino.

Open Wokwi to paste in the files (new tab)

Get the files

Use both prepared files. This is a paste-in setup; saving a project requires a Wokwi account.

diagram.json

2,829 bytes · Circuit connections

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{
  "version": 1,
  "author": "IoT Class",
  "editor": "wokwi",
  "parts": [
    {
      "type": "wokwi-esp32-devkit-v1",
      "id": "esp",
      "top": 0,
      "left": 0,
      "attrs": {}
    },
    {
      "type": "wokwi-ssd1306",
      "id": "oled1",
      "top": -100,
      "left": 150,
      "attrs": {
        "i2cAddress": "0x3c"
      }
    },
    {
      "type": "wokwi-pushbutton",
      "id": "btn1",
      "top": 100,
      "left": 200,
      "attrs": {
        "color": "green",
        "label": "UP"
      }
    },
    {
      "type": "wokwi-pushbutton",
      "id": "btn2",
      "top": 140,
      "left": 200,
      "attrs": {
        "color": "blue",
        "label": "DOWN"
      }
    },
    {
      "type": "wokwi-pushbutton",
      "id": "btn3",
      "top": 180,
      "left": 200,
      "attrs": {
        "color": "red",
        "label": "SELECT"
      }
    },
    {
      "type": "wokwi-pushbutton",
      "id": "btn4",
      "top": 220,
      "left": 200,
      "attrs": {
        "color": "yellow",
        "label": "BACK"
      }
    },
    {
      "type": "wokwi-buzzer",
      "id": "bz1",
      "top": 100,
      "left": -80,
      "attrs": {}
    }
  ],
  "connections": [
    [
      "esp:TX0",
      "$serialMonitor:RX",
      "",
      []
    ],
    [
      "esp:RX0",
      "$serialMonitor:TX",
      "",
      []
    ],
    [
      "oled1:GND",
      "esp:GND.1",
      "black",
      [
        "v-20",
        "h-60"
      ]
    ],
    [
      "oled1:VCC",
      "esp:3V3",
      "red",
      [
        "v-30",
        "h-80"
      ]
    ],
    [
      "oled1:SDA",
      "esp:D21",
      "green",
      [
        "v-40",
        "h-100"
      ]
    ],
    [
      "oled1:SCL",
      "esp:D22",
      "blue",
      [
        "v-50",
        "h-120"
      ]
    ],
    [
      "btn1:1.l",
      "esp:D25",
      "green",
      [
        "h-50"
      ]
    ],
    [
      "btn1:2.l",
      "esp:GND.1",
      "black",
      [
        "h-30",
        "v50"
      ]
    ],
    [
      "btn2:1.l",
      "esp:D26",
      "blue",
      [
        "h-60"
      ]
    ],
    [
      "btn2:2.l",
      "esp:GND.1",
      "black",
      [
        "h-40",
        "v30"
      ]
    ],
    [
      "btn3:1.l",
      "esp:D27",
      "red",
      [
        "h-70"
      ]
    ],
    [
      "btn3:2.l",
      "esp:GND.1",
      "black",
      [
        "h-50",
        "v10"
      ]
    ],
    [
      "btn4:1.l",
      "esp:D14",
      "yellow",
      [
        "h-80"
      ]
    ],
    [
      "btn4:2.l",
      "esp:GND.1",
      "black",
      [
        "h-60",
        "v-10"
      ]
    ],
    [
      "bz1:2",
      "esp:D13",
      "orange",
      [
        "h30"
      ]
    ],
    [
      "bz1:1",
      "esp:GND.1",
      "black",
      [
        "h20",
        "v30"
      ]
    ]
  ]
}

sketch.ino

16,281 bytes · ESP32 program

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/*
 * Accessible IoT Interface Lab
 *
 * Demonstrates core UI/UX accessibility principles:
 * - Multimodal feedback (visual, audio, timing)
 * - High contrast mode for visual impairments
 * - Large text mode for readability
 * - Audio confirmation sounds
 * - Persistent user preferences (NVS)
 * - Debounced button input
 *
 * Compatible with: ESP32 DevKit, Wokwi Simulator
 * Display: SSD1306 OLED 128x64 (I2C)
 */

#include <Wire.h>
#include <Adafruit_GFX.h>
#include <Adafruit_SSD1306.h>
#include <Preferences.h>

// ========== DISPLAY CONFIGURATION ==========
#define SCREEN_WIDTH 128
#define SCREEN_HEIGHT 64
#define OLED_RESET -1
#define SCREEN_ADDRESS 0x3C

Adafruit_SSD1306 display(SCREEN_WIDTH, SCREEN_HEIGHT, &Wire, OLED_RESET);

// ========== PIN DEFINITIONS ==========
#define BTN_UP 25
#define BTN_DOWN 26
#define BTN_SELECT 27
#define BTN_BACK 14
#define BUZZER_PIN 13
#define LED_PIN 2

// ========== TIMING CONSTANTS ==========
#define DEBOUNCE_DELAY 200
#define MENU_ANIMATION_DELAY 50
#define FEEDBACK_DURATION 100

// ========== AUDIO FEEDBACK FREQUENCIES ==========
#define TONE_NAVIGATE 800    // Navigation beep
#define TONE_SELECT 1200     // Selection confirmation
#define TONE_BACK 400        // Back/cancel tone
#define TONE_ERROR 200       // Error tone
#define TONE_SUCCESS 1600    // Success confirmation
#define TONE_TOGGLE_ON 1000  // Toggle enabled
#define TONE_TOGGLE_OFF 600  // Toggle disabled

// ========== USER PREFERENCES ==========
Preferences preferences;

struct AccessibilitySettings {
  bool highContrast;
  bool largeText;
  bool soundEnabled;
  uint8_t brightness;
} settings;

// ========== MENU SYSTEM ==========
enum MenuState {
  MENU_HOME,
  MENU_MAIN,
  MENU_SETTINGS,
  MENU_ACCESSIBILITY,
  MENU_SYSTEM_INFO
};

MenuState currentMenu = MENU_HOME;
int menuIndex = 0;
int maxMenuItems = 3;

// Menu item labels
const char* mainMenuItems[] = {"Home", "Settings", "System Info"};
const char* accessibilityItems[] = {"High Contrast", "Large Text", "Sound", "Brightness", "Back"};

// ========== DEBOUNCING ==========
unsigned long lastButtonPress = 0;

// ========== FUNCTION DECLARATIONS ==========
void loadSettings();
void saveSettings();
void playTone(int frequency, int duration);
void playNavigateSound();
void playSelectSound();
void playBackSound();
void playToggleSound(bool enabled);
void drawMenu();
void drawHome();
void drawMainMenu();
void drawAccessibilityMenu();
void drawSystemInfo();
void announceMenuItem(int index);
void handleNavigation(int direction);
void handleSelect();
void handleBack();
void updateDisplay();
void showFeedback(const char* message, bool success);
void blinkLED(int times);

// ========== SETUP ==========
void setup() {
  Serial.begin(115200);
  Serial.println("\n=== Accessible IoT Interface Lab ===");
  Serial.println("Demonstrating UI/UX accessibility principles");

// Initialize pins
  pinMode(BTN_UP, INPUT_PULLUP);
  pinMode(BTN_DOWN, INPUT_PULLUP);
  pinMode(BTN_SELECT, INPUT_PULLUP);
  pinMode(BTN_BACK, INPUT_PULLUP);
  pinMode(BUZZER_PIN, OUTPUT);
  pinMode(LED_PIN, OUTPUT);

// Initialize display
  Wire.begin(21, 22);
  if (!display.begin(SSD1306_SWITCHCAPVCC, SCREEN_ADDRESS)) {
    Serial.println("ERROR: SSD1306 allocation failed");
    for (;;); // Halt if display fails
  }

display.clearDisplay();
  display.setTextColor(SSD1306_WHITE);
  display.display();

// Load saved preferences
  loadSettings();

// Apply brightness setting
  display.dim(settings.brightness < 50);

// Welcome feedback
  Serial.println("Settings loaded:");
  Serial.printf("  High Contrast: %s\n", settings.highContrast ? "ON" : "OFF");
  Serial.printf("  Large Text: %s\n", settings.largeText ? "ON" : "OFF");
  Serial.printf("  Sound: %s\n", settings.soundEnabled ? "ON" : "OFF");
  Serial.printf("  Brightness: %d%%\n", settings.brightness);

// Startup sound and visual
  if (settings.soundEnabled) {
    playTone(TONE_SUCCESS, 100);
    delay(50);
    playTone(TONE_SUCCESS + 200, 100);
  }
  blinkLED(2);

// Show home screen
  drawHome();
}

// ========== MAIN LOOP ==========
void loop() {
  // Check for button presses with debouncing
  if (millis() - lastButtonPress > DEBOUNCE_DELAY) {

// UP button
    if (digitalRead(BTN_UP) == LOW) {
      lastButtonPress = millis();
      handleNavigation(-1);
      Serial.println("BTN: UP pressed");
    }

// DOWN button
    else if (digitalRead(BTN_DOWN) == LOW) {
      lastButtonPress = millis();
      handleNavigation(1);
      Serial.println("BTN: DOWN pressed");
    }

// SELECT button
    else if (digitalRead(BTN_SELECT) == LOW) {
      lastButtonPress = millis();
      handleSelect();
      Serial.println("BTN: SELECT pressed");
    }

// BACK button
    else if (digitalRead(BTN_BACK) == LOW) {
      lastButtonPress = millis();
      handleBack();
      Serial.println("BTN: BACK pressed");
    }
  }

delay(10); // Small delay for stability
}

// ========== SETTINGS MANAGEMENT ==========
void loadSettings() {
  preferences.begin("access", false);
  settings.highContrast = preferences.getBool("contrast", false);
  settings.largeText = preferences.getBool("largetext", false);
  settings.soundEnabled = preferences.getBool("sound", true);
  settings.brightness = preferences.getUChar("brightness", 100);
  preferences.end();
}

void saveSettings() {
  preferences.begin("access", false);
  preferences.putBool("contrast", settings.highContrast);
  preferences.putBool("largetext", settings.largeText);
  preferences.putBool("sound", settings.soundEnabled);
  preferences.putUChar("brightness", settings.brightness);
  preferences.end();
  Serial.println("Settings saved to NVS");
}

// ========== AUDIO FEEDBACK ==========
void playTone(int frequency, int duration) {
  if (!settings.soundEnabled) return;
  tone(BUZZER_PIN, frequency, duration);
  delay(duration);
  noTone(BUZZER_PIN);
}

void playNavigateSound() {
  playTone(TONE_NAVIGATE, 30);
}

void playSelectSound() {
  playTone(TONE_SELECT, 50);
  delay(30);
  playTone(TONE_SELECT + 200, 50);
}

void playBackSound() {
  playTone(TONE_BACK, 80);
}

void playToggleSound(bool enabled) {
  if (enabled) {
    playTone(TONE_TOGGLE_ON, 50);
    delay(30);
    playTone(TONE_TOGGLE_ON + 400, 80);
  } else {
    playTone(TONE_TOGGLE_OFF + 200, 50);
    delay(30);
    playTone(TONE_TOGGLE_OFF, 80);
  }
}

void playErrorSound() {
  playTone(TONE_ERROR, 100);
  delay(50);
  playTone(TONE_ERROR, 100);
}

// ========== VISUAL FEEDBACK ==========
void blinkLED(int times) {
  for (int i = 0; i < times; i++) {
    digitalWrite(LED_PIN, HIGH);
    delay(100);
    digitalWrite(LED_PIN, LOW);
    delay(100);
  }
}

void showFeedback(const char* message, bool success) {
  // Visual feedback on display
  display.fillRect(0, 54, 128, 10, settings.highContrast ? SSD1306_WHITE : SSD1306_BLACK);
  display.setTextColor(settings.highContrast ? SSD1306_BLACK : SSD1306_WHITE);
  display.setTextSize(1);
  display.setCursor(4, 55);
  display.print(message);
  display.display();

// Audio feedback
  if (success) {
    playTone(TONE_SUCCESS, 100);
  } else {
    playErrorSound();
  }

// LED feedback
  blinkLED(success ? 1 : 3);

delay(500);
  updateDisplay();
}

// ========== NAVIGATION HANDLING ==========
void announceMenuItem(int index) {
  Serial.print("Selected: ");
  Serial.println(accessibilityItems[index]);

// Announce current state for toggles
  switch (index) {
    case 0:
      Serial.printf("High Contrast is currently %s\n",
                    settings.highContrast ? "ON" : "OFF");
      break;
    case 1:
      Serial.printf("Large Text is currently %s\n",
                    settings.largeText ? "ON" : "OFF");
      break;
  }
}

void handleNavigation(int direction) {
  menuIndex += direction;

// Wrap around menu
  if (menuIndex < 0) menuIndex = maxMenuItems - 1;
  if (menuIndex >= maxMenuItems) menuIndex = 0;

if (currentMenu == MENU_ACCESSIBILITY) announceMenuItem(menuIndex);
  playNavigateSound();
  blinkLED(1);
  updateDisplay();
}

void handleSelect() {
  playSelectSound();
  blinkLED(1);

switch (currentMenu) {
    case MENU_HOME:
      currentMenu = MENU_MAIN;
      menuIndex = 0;
      maxMenuItems = 3;
      break;

case MENU_MAIN:
      switch (menuIndex) {
        case 0: // Home
          currentMenu = MENU_HOME;
          break;
        case 1: // Settings -> Accessibility
          currentMenu = MENU_ACCESSIBILITY;
          menuIndex = 0;
          maxMenuItems = 5;
          break;
        case 2: // System Info
          currentMenu = MENU_SYSTEM_INFO;
          break;
      }
      break;

case MENU_ACCESSIBILITY:
      switch (menuIndex) {
        case 0: // Toggle High Contrast
          settings.highContrast = !settings.highContrast;
          playToggleSound(settings.highContrast);
          saveSettings();
          Serial.printf("High Contrast: %s\n", settings.highContrast ? "ON" : "OFF");
          break;
        case 1: // Toggle Large Text
          settings.largeText = !settings.largeText;
          playToggleSound(settings.largeText);
          saveSettings();
          Serial.printf("Large Text: %s\n", settings.largeText ? "ON" : "OFF");
          break;
        case 2: // Toggle Sound
          settings.soundEnabled = !settings.soundEnabled;
          // Play sound BEFORE disabling
          if (!settings.soundEnabled) {
            tone(BUZZER_PIN, TONE_TOGGLE_OFF + 200, 50);
            delay(30);
            tone(BUZZER_PIN, TONE_TOGGLE_OFF, 80);
            noTone(BUZZER_PIN);
          } else {
            playToggleSound(true);
          }
          saveSettings();
          Serial.printf("Sound: %s\n", settings.soundEnabled ? "ON" : "OFF");
          break;
        case 3: // Adjust Brightness
          settings.brightness += 25;
          if (settings.brightness > 100) settings.brightness = 25;
          display.dim(settings.brightness < 50);
          playTone(800 + (settings.brightness * 8), 50);
          saveSettings();
          Serial.printf("Brightness: %d%%\n", settings.brightness);
          break;
        case 4: // Back
          handleBack();
          return;
      }
      break;

case MENU_SYSTEM_INFO:
      // Return to main menu
      handleBack();
      return;
  }

updateDisplay();
}

void handleBack() {
  playBackSound();
  blinkLED(1);

switch (currentMenu) {
    case MENU_HOME:
      // Already at home, do nothing
      break;
    case MENU_MAIN:
      currentMenu = MENU_HOME;
      break;
    case MENU_ACCESSIBILITY:
    case MENU_SYSTEM_INFO:
      currentMenu = MENU_MAIN;
      menuIndex = 0;
      maxMenuItems = 3;
      break;
  }

updateDisplay();
}

// ========== DISPLAY RENDERING ==========
void updateDisplay() {
  switch (currentMenu) {
    case MENU_HOME:
      drawHome();
      break;
    case MENU_MAIN:
      drawMainMenu();
      break;
    case MENU_ACCESSIBILITY:
      drawAccessibilityMenu();
      break;
    case MENU_SYSTEM_INFO:
      drawSystemInfo();
      break;
  }
}

void drawHome() {
  display.clearDisplay();

// Background for high contrast mode
  if (settings.highContrast) {
    display.fillScreen(SSD1306_WHITE);
    display.setTextColor(SSD1306_BLACK);
  } else {
    display.setTextColor(SSD1306_WHITE);
  }

// Title
  display.setTextSize(settings.largeText ? 2 : 1);
  display.setCursor(settings.largeText ? 10 : 25, 4);
  display.print("IoT Device");

// Status indicator with icon
  display.setTextSize(1);
  display.setCursor(4, settings.largeText ? 28 : 20);
  display.print("Status: ");
  display.print("ONLINE");

// Draw status indicator circle
  int circleX = settings.largeText ? 100 : 75;
  int circleY = settings.largeText ? 32 : 23;
  if (settings.highContrast) {
    display.fillCircle(circleX, circleY, 4, SSD1306_BLACK);
  } else {
    display.fillCircle(circleX, circleY, 4, SSD1306_WHITE);
  }

// Show active accessibility features
  display.setCursor(4, settings.largeText ? 44 : 36);
  if (settings.highContrast || settings.largeText) {
    display.print("A11y: ");
    if (settings.highContrast) display.print("HC ");
    if (settings.largeText) display.print("LT ");
  }

// Navigation hint
  display.setCursor(4, 54);
  display.setTextSize(1);
  display.print("[SELECT] Open Menu");

display.display();
}

void drawMainMenu() {
  display.clearDisplay();

if (settings.highContrast) {
    display.fillScreen(SSD1306_WHITE);
    display.setTextColor(SSD1306_BLACK);
  } else {
    display.setTextColor(SSD1306_WHITE);
  }

// Title
  display.setTextSize(settings.largeText ? 2 : 1);
  display.setCursor(settings.largeText ? 20 : 40, 2);
  display.print("MENU");

// Draw menu items
  display.setTextSize(settings.largeText ? 2 : 1);
  int yStart = settings.largeText ? 22 : 18;
  int ySpacing = settings.largeText ? 14 : 12;

for (int i = 0; i < 3; i++) {
    int y = yStart + (i * ySpacing);

// Highlight selected item
    if (i == menuIndex) {
      if (settings.highContrast) {
        display.fillRect(0, y - 2, 128, ySpacing, SSD1306_BLACK);
        display.setTextColor(SSD1306_WHITE);
      } else {
        display.fillRect(0, y - 2, 128, ySpacing, SSD1306_WHITE);
        display.setTextColor(SSD1306_BLACK);
      }
      display.setCursor(4, y);
      display.print("> ");
    } else {
      display.setTextColor(settings.highContrast ? SSD1306_BLACK : SSD1306_WHITE);
      display.setCursor(4, y);
      display.print("  ");
    }
    display.print(mainMenuItems[i]);
  }

// Navigation hints
  display.setTextSize(1);
  display.setTextColor(settings.highContrast ? SSD1306_BLACK : SSD1306_WHITE);
  display.setCursor(4, 54);
  display.print("[UP/DN] Nav [SEL] OK");

display.display();
}

void drawAccessibilityMenu() {
  display.clearDisplay();

if (settings.highContrast) {
    display.fillScreen(SSD1306_WHITE);
    display.setTextColor(SSD1306_BLACK);
  } else {
    display.setTextColor(SSD1306_WHITE);
  }

// Title
  display.setTextSize(1);
  display.setCursor(20, 2);
  display.print("ACCESSIBILITY");

// Draw menu items with current values
  int yStart = 14;
  int ySpacing = 10;

for (int i = 0; i < 5; i++) {
    int y = yStart + (i * ySpacing);

// Highlight selected item
    if (i == menuIndex) {
      if (settings.highContrast) {
        display.fillRect(0, y - 1, 128, ySpacing, SSD1306_BLACK);
        display.setTextColor(SSD1306_WHITE);
      } else {
        display.fillRect(0, y - 1, 128, ySpacing, SSD1306_WHITE);
        display.setTextColor(SSD1306_BLACK);
      }
    } else {
      display.setTextColor(settings.highContrast ? SSD1306_BLACK : SSD1306_WHITE);
    }

display.setCursor(4, y);
    if (i == menuIndex) display.print(">");
    display.setCursor(12, y);
    display.print(accessibilityItems[i]);

// Show current values
    display.setCursor(90, y);
    switch (i) {
      case 0: display.print(settings.highContrast ? "[ON]" : "[OFF]"); break;
      case 1: display.print(settings.largeText ? "[ON]" : "[OFF]"); break;
      case 2: display.print(settings.soundEnabled ? "[ON]" : "[OFF]"); break;
      case 3:
        display.print("[");
        display.print(settings.brightness);
        display.print("%]");
        break;
      case 4: display.print(""); break;
    }
  }

// Navigation hints
  display.setTextColor(settings.highContrast ? SSD1306_BLACK : SSD1306_WHITE);
  display.setCursor(4, 54);
  display.print("[SEL] Toggle [BACK]");

display.display();
}

void drawSystemInfo() {
  display.clearDisplay();

if (settings.highContrast) {
    display.fillScreen(SSD1306_WHITE);
    display.setTextColor(SSD1306_BLACK);
  } else {
    display.setTextColor(SSD1306_WHITE);
  }

// Title
  display.setTextSize(1);
  display.setCursor(25, 2);
  display.print("SYSTEM INFO");

// System information
  display.setCursor(4, 16);
  display.print("Device: ESP32");

display.setCursor(4, 26);
  display.print("Uptime: ");
  display.print(millis() / 1000);
  display.print("s");

display.setCursor(4, 36);
  display.print("Free Heap: ");
  display.print(ESP.getFreeHeap() / 1024);
  display.print("KB");

display.setCursor(4, 46);
  display.print("Display: 128x64 OLED");

// Navigation hint
  display.setCursor(4, 54);
  display.print("[BACK] Return");

display.display();
}

Use the launch button above to open the ESP32 editor in Wokwi.
Select the editor’s diagram.json tab and replace all its text with the supplied diagram.json.
Select the sketch.ino tab, replace all its text with the supplied sketch.ino, then click Start Simulation.

Steps

Screens captured against Wokwi ESP32 Compiled and booted by the Wokwi gate (ESP32 Arduino core 3.3.11); captured in the Wokwi web editor on 2026-09-09 on 2026-09-09; the tool may have moved on — the text steps are the contract.

Step 1
Do
Paste the diagram and sketch into Wokwi ESP32 and install Adafruit GFX Library and Adafruit SSD1306. Inspect the four labelled buttons.
You will see
UP, DOWN, SELECT, and BACK connect to GPIO 25, 26, 27, and 14. OLED SDA/SCL use GPIO 21/22; the buzzer uses GPIO 13.
Why it matters
Consistent controls and multiple feedback channels support the host’s principle of making important state easy to find.
Step 2
Do
Start at 115200 baud and read the settings printed at startup.
You will see
A fresh run reports High Contrast: OFF, Large Text: OFF, Sound: ON, and Brightness: 100%. The OLED opens on the home screen.
Why it matters
Start with explicit state rather than inferring settings from a tone. Saved preferences can change these initial values.
Step 3
Do
Tap SELECT, then DOWN once to Settings, then SELECT again. Release each button between taps.
You will see
The OLED opens ACCESSIBILITY with High Contrast selected. Serial prints the corresponding BTN messages.
Why it matters
The supplied extension announces navigation inside this menu; entering the menu itself does not yet announce its first item.
Step 4
Do
Tap DOWN once, then UP once, watching Serial Monitor.
You will see
Selected: Large Text and Large Text is currently OFF appear, followed by Selected: High Contrast and High Contrast is currently OFF on a fresh run.
Why it matters
The extension conveys both a label and its current toggle state, so the information is available without relying only on the highlight.
Step 5
Do
With High Contrast selected, tap SELECT; then tap DOWN and UP to revisit it.
You will see
Serial prints High Contrast: ON and Settings saved to NVS; revisiting prints High Contrast is currently ON. The OLED reverses foreground and background.
Why it matters
The action result and subsequent state announcement should agree. This is the same consistency needed between a dashboard control and its displayed status.
Step 6
Do
Tap DOWN to Large Text, select it, then move away and back.
You will see
Large Text: ON appears when selected, and Large Text is currently ON appears when revisited. The accessibility list itself stays at its fixed small font.
Why it matters
A stored preference is not proof that every screen respects it. The source applies large text on home and main menu screens, leaving an accessibility gap in this list.
Step 7
Do
Continue DOWN to Sound and Brightness, comparing their announcements with the OLED values.
You will see
Serial announces Selected: Sound and Selected: Brightness but does not announce their values. The OLED still shows those values.
Why it matters
The supplied function only announces states for its first two toggles. Identify this limitation before claiming complete nonvisual navigation or adding more alerts.

Chapter checks

These questions refer to the chapter’s examples. Use the return links to review their answers.

You're designing a dashboard for a factory floor monitoring system. The operator needs to see: (1) machine status (running/stopped/error), (2) production count, (3) temperature readings, and (4) 7-day production trends. Where should you place the machine status indicator?
Return to the chapter’s knowledge check
A smart building dashboard monitors HVAC systems. Temperature thresholds are set to: Normal (18-24 C), Warning (15-18 or 24-28 C), Critical (<15 or >28 C). During testing, operators complain about 'alert fatigue' - too many warnings. Analysis shows 85% of warnings occur briefly during HVAC startup. What's the BEST solution?
Return to the chapter’s knowledge check

Return to Interface Design: Dashboards · Browse Labs

Wokwi ESP32

Get the files

diagram.json

sketch.ino

Steps

1 Step 1

2 Step 2

3 Step 3

4 Step 4

5 Step 5

6 Step 6

7 Step 7

Chapter checks

Step 1

Step 2

Step 3

Step 4

Step 5

Step 6

Step 7