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📌 Overview

The input device uses:

• 1 Potentiometer for character selection
• 3 Buttons for mode control and actions
• 4 Character Modes (letters, numbers, symbols)
• Advanced input detection (double-press, long-press)

🛠 Hardware Setup

Component	Pin	Notes
Potentiometer	A0	10kΩ recommended
Mode Button	10	INPUT_PULLUP
Confirm Button	11	INPUT_PULLUP
ESC Button	12	INPUT_PULLUP

🔢 Character Modes

📜 List of characters

const char* modes[] = {
  "abcdefghijklmnopqrstuvwxyz",  // Mode 0
  "ABCDEFGHIJKLMNOPQRSTUVWXYZ",  // Mode 1 
  "0123456789$%#@&",             // Mode 2
  ".,!?;:'\"-()/\\ "             // Mode 3
};

🎮 Complete Control Reference

🔄 Mode Button (Pin 10)

Action	Effect	Technical Details
Single Press	Cycles modes (0→1→2→3→0)	currentMode = (currentMode + 1) % 4
Double Press	Sends "Enter"	if (millis() - lastModePressTime < 500ms)
Long Press (300ms+)	Toggles CapsLock (Modes 0/1)	capsLock = !capsLock

✅ Confirm Button (Pin 11)

Action	Effect
Short Press	Prints selected character
Long Press (300ms+)	Prints space character

⏮ ESC Button (Pin 12)

Action	Effect
Short Press	"ESC" command
Long Press (300ms+)	"Backspace" command

📟 Serial Output Examples

Selected: [a] | Mode: Lowercase Letters
Confirmed: b
Caps Lock: ON
Backspace
Enter
Space inserted

⚙️ Configuration Constants

const int holdDelay = 300;       // Long-press threshold (ms)
const int doublePressDelay = 500; // Double-press window (ms)
const int potRange = 670;        // Potentiometer range (0-potRange)

🔄 Mode Transition Logic

graph TD
    A[Lowercase] -->|Single Press| B[Uppercase]
    B -->|Single Press| C[Numbers/Symbols]
    C -->|Single Press| D[Punctuation]
    D -->|Single Press| A
    A <-->|Long Press| B

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🚦 Status Tracking

The system tracks:

• currentMode (0-3)
• capsLock (boolean)
• selectedCharIndex (0 to strlen(currentMode)-1)
• lastPrintedCharIndex (for change detection)
• lastPrintedMode (for change detection)

🕹 Usage Example

1. Rotate dial to 'A'
2. Short-press Confirm → "Confirmed: A"
3. Long-press Mode → "Caps Lock: ON"
4. Double-press Mode → "Enter"
5. Long-press ESC → "Backspace"

⚠️ More Troubleshooting

Issue	Solution
Characters skipping	Check potentiometer wiring
Buttons not responding	Verify INPUT_PULLUP enabled
Serial output lag	Reduce loop() delay (currently 100ms)
Incorrect mode changes	Calibrate holdDelay (300ms)

Refer to README for basic problems.

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📁 See also: Main Repository | Schematic Diagram