Arduino Fans

I have a small hatchback car with manual transmission and I often think to display current gear in the dashboard instrument panel, So I decided to make something fancy, In this tutorial we are going to build a car gear position indicator for a manual transmission (H-pattern) with 5 forward gears + 1 reverse using:

• Arduino Nano
• 6 Limit Switches (for gear detection)
• 0.96″ I2C OLED Display (typically SSD1306, 128×64)

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⚙️ System Overview

Each gear position has a dedicated limit switch:

• Gear 1 → Switch 1
• Gear 2 → Switch 2
• …
• Gear R (reverse) → Switch 6

You’ll read these switches as digital inputs and display the active gear on the OLED.

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🧰 Components Needed

• Arduino Nano
• SSD1306 OLED (I2C)
• 6x Limit Switches
• Pull-down resistors (or use internal pull-ups and wire switches to ground)
• Jumper wires, breadboard or PCB

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⚙️ Concept: H-Pattern Manual Transmission Gear Indicator

Goal: Display a visually clear and attractive H-pattern gear layout with real-time gear selection based on limit switch input.

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🧩 Components Breakdown

Component	Purpose
Arduino Nano	Reads gear position from limit switches
6 Limit Switches	One per gear (1–5 + R), mounted to shifter
OLED Display	Shows the H-pattern layout with gear labels
Graphics (OLED or Simulation)	Visual representation of gear state

🖥️ OLED Wiring (I2C)

OLED Pin	Arduino Nano Pin
VCC	5V
GND	GND
SDA	A4
SCL	A5

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🔌 Limit Switch Wiring Example

Wire one side of each limit switch to GND, the other side to a digital pin (D2–D7 for example). Enable internal pull-up resistors in code.

🛠️ Notes

• When no gear is engaged, all switches are unpressed → system shows “N” (Neutral).
• You can improve it by debouncing the switch inputs if needed.
• Mount the switches such that only one is pressed at a time.
• If 2 or more are pressed (like during shift), you can prioritize or show “Shifting”.

🔲 OLED Gear Layout Example (H Pattern)

1   3   5
|   |   |
2   4   R

We’ll draw all gears statically, and dynamically highlight the active gear by inverting its number (or drawing a box around it).

🧾 Arduino Code – H Pattern Gear Display with Highlight

Ensure you have these libraries installed:

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

🔧 Customization Tips

• You can adjust gearX and gearY values to better fit your screen or layout.
• Add connecting lines between gears if desired (like drawing vertical/horizontal lines for realism).
• Add an optional "N" (Neutral) box if no gear is pressed.

✅ Features

• Full H-pattern layout
• Gear connections (lines)
• Highlighted active gear
• Optional Neutral display if no gear is selected
• Smooth and clean layout

🖥️ How It Works

1. Gear Detection via Limit Switches

Each gear position in your physical gear shifter presses a unique limit switch when selected.

• Limit switches are connected to digital pins on the Arduino Nano.
• Each switch is pulled HIGH via INPUT_PULLUP.
• When a gear is engaged, its switch goes LOW → Arduino detects it.

2. Gear Mapping Logic

In the Arduino sketch:

• We scan all switch inputs.
• The first detected LOW input tells us which gear is active.
• If no gear is active, we consider it Neutral.

3. OLED Display Update

Based on the active gear:

• A pre-drawn H-pattern is shown with all gear positions.
• The current gear is highlighted (by color inversion or glow effect).
• If no gear is pressed, a Neutral “N” is displayed.

🧾 Arduino Code upload by using Arduino IDE

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

#define SCREEN_WIDTH 128
#define SCREEN_HEIGHT 64

Adafruit_SSD1306 display(SCREEN_WIDTH, SCREEN_HEIGHT, &Wire, -1);

// Gear switch pins: 1 to 5 and Reverse
const int gearPins[6] = {2, 3, 4, 5, 6, 7};
const char* gearLabels[6] = {"1", "2", "3", "4", "5", "R"};

// Gear screen positions
const int gearX[6] = {10, 10, 50, 50, 90, 90}; // x-coords
const int gearY[6] = {0, 30, 0, 30, 0, 30};    // y-coords

int activeGear = -1;

void setup() {
  for (int i = 0; i < 6; i++) {
    pinMode(gearPins[i], INPUT_PULLUP);
  }

  if (!display.begin(SSD1306_SWITCHCAPVCC, 0x3C)) {
    while (true); // halt if OLED not found
  }

  display.clearDisplay();
  display.display();
}

void loop() {
  activeGear = -1;
  for (int i = 0; i < 6; i++) {
    if (digitalRead(gearPins[i]) == LOW) {
      activeGear = i;
      break;
    }
  }

  drawHPattern(activeGear);
  delay(100);
}

void drawHPattern(int highlight) {
  display.clearDisplay();

  // Draw vertical lines (gear gates)
  display.drawLine(18, 10, 18, 54, SSD1306_WHITE); // 1-2
  display.drawLine(58, 10, 58, 54, SSD1306_WHITE); // 3-4
  display.drawLine(98, 10, 98, 54, SSD1306_WHITE); // 5-R

  // Draw horizontal connectors
  display.drawLine(18, 20, 98, 20, SSD1306_WHITE); // upper line
  display.drawLine(18, 44, 98, 44, SSD1306_WHITE); // lower line

  // Draw gear numbers
  for (int i = 0; i < 6; i++) {
    int x = gearX[i];
    int y = gearY[i];

    if (i == highlight) {
      display.fillRect(x - 2, y - 2, 20, 18, SSD1306_WHITE);
      display.setTextColor(SSD1306_BLACK);
    } else {
      display.setTextColor(SSD1306_WHITE);
    }

    display.setTextSize(2);
    display.setCursor(x, y);
    display.print(gearLabels[i]);
  }

  // Optional: Show Neutral if no gear is selected
  if (highlight == -1) {
    display.setTextSize(2);
    display.setTextColor(SSD1306_WHITE);
    display.setCursor(40, 48);
    display.print("N");
  }

  display.display();
}

🧰 Notes

• You can change the line coordinates if your OLED is a different resolution.
• Works best with 128×64 OLEDs (SSD1306).
• All six gears are laid out in an accurate H-pattern.
• The highlighted gear gets inverted colors for visibility.
• If no switch is pressed, “N” (Neutral) is shown.

✅ Conclusion: Manual Transmission Gear Indicator with H-Pattern

You’ve now built a functional and visually enhanced gear position indicator for a manual transmission car using:

• Arduino Nano for logic and input reading
• Limit switches for real-time gear detection
• 0.96″ OLED display to show a classic H-pattern with highlighted gear feedback

This setup provides a clear, intuitive way to monitor gear selection on both physical and graphical interfaces. It’s especially useful for simulators, DIY dashboard projects, or driver training rigs.

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🛠️ Suggested Improvements and Tips

1. Debounce Switch Inputs

Avoid gear flickering or false reads:

delay(20); // small debounce delay

Or implement proper software debouncing using millis().

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2. Neutral Detection Enhancements

Currently, Neutral is when no gear is pressed. To improve:

• Add a dedicated “Neutral” switch
• Or detect the state where the stick is between gates

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3. Add Sound or Haptic Feedback

• A small piezo buzzer for gear change tones
• Or vibrational feedback if you want tactile confirmation

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4. Animated Transitions

Use frame-based drawing for smoother gear change animation:

• Slide highlight boxes
• Fade effects when switching gears

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5. Backlit or Themed Displays

• Use color OLED (if available) for vibrant themes
• Customize gear highlight color (e.g., red for R, blue for normal gears)

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6. Serial Output or Logging

• Send gear changes via Serial.print() for debugging or telemetry logging
• Integrate with an app or data logger

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7. Upgrade Display for Advanced UI

• Use a TFT display (e.g., 1.8″ or 2.4″ SPI TFT) for full-color, richer graphics
• Integrate touchscreen to simulate automatic/manual mode switching

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8. Encapsulate in a Dashboard Housing

Build a physical enclosure for the screen and gear detector:

• Use 3D printed or laser-cut dashboard panel
• Mount switches firmly under the shifter gate