⚡ Vaidyuthi Cluster v1

A real-time vehicle dashboard built on the Arduino Uno, displaying speed, voltage, time, and date on a 128×64 SSD1306 OLED — styled as a motorcycle instrument cluster with an arc speedometer and segmented battery bar.

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Project Structure

vaidyuthi-cluster/
├── Vaidyuthi_Cluster_v3.ino   # Main Arduino sketch
└── README.md                  # This file

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Display Layout

+--------------------------------------+
| 12:34                       01/06   |
|   ╭──────────╮  ┊  BATT             |
|   │    52    │  ┊  [████░░░░░░]     |
|   │  KM/H    │  ┊  12.4V   74%      |
|   ╰──────────╯  ┊                   |
| AUTO                                |
+--------------------------------------+

Zone	Content
Top-left	Live time HH:MM from DS3231 RTC
Top-right	Live date DD/MM from DS3231 RTC
Left panel	Arc speedometer with tick marks + big speed number
Right panel	BATT label + 6-segment battery bar + voltage + %
Bottom-left	Current mode (AUTO)

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Features

• Arc speedometer - 270° sweep with dotted track, 3px thick fill, major/minor tick marks, and a dominant large speed number at the centre
• Segmented battery bar - 6-segment horizontal bar with positive terminal nub; fills proportionally to input voltage (10.2V–14.8V range)
• Live voltage readout - displays actual measured voltage (e.g. 12.4V) and charge percentage below the battery bar
• Low voltage warning - a blinking ! appears at the bottom-right when battery drops below 20%
• Live RTC clock - time and date pulled from DS3231 on every refresh
• IIR sensor smoothing - both speed and voltage are low-pass filtered (α = 0.2) to prevent needle jitter
• Help screen - hold the button for 2 seconds to show a contact/support screen & release to return instantly
• One-time boot splash - "Hi, Rohith" and "Welcome to VAIDYUTHI" screens shown once on power-up and never again
• ~12 fps refresh - redraws every 80 ms using millis(); no blocking code in the main loop

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Hardware

Component	Details
MCU	Arduino Uno (ATmega328P)
Display	SSD1306 OLED 128×64 (I2C, address 0x3C)
RTC	DS3231 (I2C)
Voltage sensor	Resistive voltage divider -> Pin A0
Speed sensor	Analog voltage output -> Pin A1
Button	Tactile switch -> Pin D2 (active LOW, internal pull-up)

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Wiring

I2C Bus - shared by OLED and DS3231

Arduino Pin	Connects To
A4 (SDA)	SSD1306 SDA + DS3231 SDA
A5 (SCL)	SSD1306 SCL + DS3231 SCL
5V	VCC of both modules
GND	GND of both modules

Analog Inputs

Arduino Pin	Connects To
A0	Voltage divider midpoint (wiper)
A1	Speed sensor analog output

Button

Arduino Pin	Connects To
D2	One leg of tactile button
GND	Other leg of tactile button

Internal pull-up is enabled in firmware — no external resistor needed.

Voltage Divider (for A0)

Vin ──── R1 (30kΩ) ──┬── R2 (7.5kΩ) ──── GND
                     │
                  A0 (Arduino)

Supported input range: up to ~25V
Battery percentage range: 10.2V = 0% → 14.8V = 100%

Adjust R1, R2, VOLT_MIN, and VOLT_MAX in the sketch to match your resistors and battery chemistry.

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Required Libraries

Install all three via Arduino IDE → Tools → Manage Libraries:

Library	Author
Adafruit SSD1306	Adafruit
Adafruit GFX Library	Adafruit
RTClib	Adafruit

⚠️ Do not add #include <math.h> to this sketch. The Arduino core already provides cos() and sin(). Including <math.h> explicitly causes a silent hang on AVR targets after the splash screens finish.

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Getting Started

1. Clone the repository

git clone https://github.com/Rohith-Kalarikkal/vaidyuthi-cluster-firmware.git

2. Install the three libraries listed above via the Arduino Library Manager.

3. Set the RTC time

Open vaidyuthi_cluster_v1.ino and uncomment this line near the bottom of setup():

// rtc.adjust(DateTime(F(__DATE__), F(__TIME__)));

Upload once. The RTC will sync to your computer's compile time. Then immediately re-comment the line and upload again — this prevents the clock from resetting on every reboot.

4. Calibrate your sensors

Edit these constants near the top of the sketch:

const float R1       = 30.0f;   // upper voltage-divider resistor (kΩ)
const float R2       =  7.5f;   // lower voltage-divider resistor (kΩ)
const float VREF     =  5.0f;   // Arduino Vcc
const float VOLT_MIN = 10.2f;   // voltage shown as 0% battery
const float VOLT_MAX = 14.8f;   // voltage shown as 100% battery
const float SPD_MAX  = 100.0f;  // speed (km/h) at full ADC reading

5. Upload and run.

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Boot Sequence

Power on
   │
   ▼
"Hi, Rohith"
(2 seconds)
   │
   ▼
"Welcome to VAIDYUTHI"
(2 seconds)
   │
   ▼
Main Dashboard  ◄──────────────────────────────┐
   │                                           │
   │  Button held ≥ 2s                         │ Button released
   ▼                                           │
Help Screen ───────────────────────────────────┘

Splash screens run exactly once inside setup() using delay(). After setup() returns, loop() contains no splash logic whatsoever — it is impossible for the splashes to reappear without a full power cycle.

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Button Reference

Action	Result
Hold ≥ 2 seconds on main screen	Switch to Help screen
Release button while on Help screen	Return to main dashboard

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Configuration Reference

Constant	Default	Description
R1	30.0	Upper resistor of voltage divider (kΩ)
R2	7.5	Lower resistor of voltage divider (kΩ)
VREF	5.0	Arduino ADC reference voltage (V)
VOLT_MIN	10.2	Voltage mapped to 0% battery
VOLT_MAX	14.8	Voltage mapped to 100% battery
SPD_MAX	100.0	Speed at full ADC reading (km/h)
REFRESH_MS	80	Display refresh interval in ms (~12 fps)
HOLD_MS	2000	Button hold duration to enter Help (ms)

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Fault Indicators

Condition	Behaviour
SSD1306 not detected at boot	Built-in LED blinks rapidly and halts
DS3231 not detected at boot	OLED shows RTC FAIL and halts
Battery charge below 20%	Blinking ! at bottom-right of dashboard

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Extending the Project

• Frequency-based speed sensor — replace the linear ADC mapping with a pulse-counting ISR using attachInterrupt() on D2 or D3 for Hall-effect wheel sensors
• Mode cycling — add a short-press handler to toggle between display modes (e.g. trip meter, temperature); a modeIndex variable and a switch inside drawMain() is all you need
• Different battery chemistry — change VOLT_MIN/VOLT_MAX to match your pack (e.g. 6.0/8.4 for 2S LiPo, 9.0/12.6 for 3S LiPo, 11.0/14.6 for LiFePO4)
• Higher speed range — increase SPD_MAX to 150 or 200 and recalibrate the sensor

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License

Released under the MIT License.