Open-source ESP32-S3 cryptocurrency price display with e-ink screen and encoder control—an affordable, customizable alternative to overpriced commercial tickers.
Three CryptoBar units stacked using magnets, displaying real-time cryptocurrency prices with LED status indicators
CryptoBar is an ESP32-S3-based cryptocurrency display that started as a personal challenge to build a better, cheaper alternative to expensive commercial solutions like Tickrmeter. Frustrated with overpriced devices packed with features most users never need, CryptoBar delivers what you actually want: real-time crypto prices, clean display, and intuitive rotary encoder navigation—all without smartphone app dependency.
Two Display Options:
- E-ink Edition (Standard): Low-power 2.9" e-ink display with charts and graphs
- VFD Edition (Retro): 16-character vacuum fluorescent display with nostalgic glow
Now open-sourced for the maker community, CryptoBar offers complete hardware and software customization at a fraction of the cost of commercial alternatives.
- ✅ Affordable: DIY build costs significantly less than commercial alternatives
- ✅ No Phone Required: Hardware encoder navigation, no app needed
- ✅ Customizable: Open-source hardware and software
- ✅ Reliable: Multi-layer API fallback system (4 data sources)
- ✅ Low Power: E-ink display for always-on operation
- ✅ Professional: Clean design with 3D printed enclosure
- 📊 Dual Display Support - Choose your style:
- E-ink: 2.9" display with charts, low power, always readable
- VFD: 16-char retro display with auto brightness and anti-burn-in
- 🎛️ Rotary Encoder Navigation - Intuitive menu control with push-button
- 🎨 RGB LED Status Indicator - Price trends with party mode for +20% gains
- ⏰ Timezone-Aware Clock - Auto-detection with 27 timezone options (UTC-12 to UTC+14)
- 🪙 21 Cryptocurrencies: BTC, ETH, BNB, XRP, SOL, TRX, DOGE, ADA, BCH, LINK, XMR, XLM, LTC, AVAX, HBAR, SHIB, TON, UNI, DOT, KAS, FLR (sorted by market cap)
- 💱 9 Display Currencies: USD, TWD, EUR, GBP, CAD, JPY, KRW, SGD, AUD
- 📈 24-Hour Price Charts - Visual price history on e-ink display
- 📊 24h Change Percentage - Real-time gain/loss tracking
- 🔄 Multi-Layer API Fallback:
- CoinGecko (aggregated data from 500+ exchanges)
- CoinPaprika (aggregated data from 200+ exchanges)
- Kraken (direct exchange data)
- Binance (direct exchange data)
- ⏱️ Configurable Update Intervals: 1min, 3min (recommended), 5min, 10min
- 🌐 Distributed API Load: MAC-based jitter prevents rate limit issues
- 🎯 High Precision: Full 14-16 decimal place accuracy from CoinGecko
- 🔄 Independent Time Refresh: Clock updates every minute regardless of price interval
- 📊 Day Average Modes: Off, Rolling 24h, ET 7pm cycle
- 🎚️ LED Brightness Control: Low / Medium / High
- 🔃 Display Refresh Modes: Partial (battery-friendly) / Full (ghosting-free)
- 📡 OTA Firmware Updates: Update wirelessly via web interface
- 🌐 WiFi Configuration Portal: Easy setup through captive portal
Professional 3D-printed enclosure with rotary encoder knob and LED light diffuser
| Component | Specifications | Quantity | Amazon Link |
|---|---|---|---|
| ESP32-S3 Development Board | N16R8 (16MB Flash, 8MB PSRAM) | 1 | Buy on Amazon |
| E-ink Display | WaveShare 2.9" B&W e-Paper Module | 1 | Buy on Amazon |
| Rotary Encoder | KY-040 Module with Ribbon Cable | 1 | Buy on Amazon |
| RGB LED | WS2812B LED Strip (need 1 LED) | 1 | Buy on Amazon |
| Component | Quantity | Amazon Link |
|---|---|---|
| M3 x 8mm Hex Screws | 2 | Buy Kit |
| M2 x 5mm Flat Head Screws | 4 | Buy Kit |
| M3 Heat Set Inserts | 2 | Buy |
| M2 Heat Set Inserts | 4 | Buy |
Note: Many components come in multi-packs. Consider building multiple units to maximize value.
| Component | Recommended Product | Amazon Link |
|---|---|---|
| Black PLA Filament | PolyMaker Matte Black PLA (enclosure parts) | Buy on Amazon |
| White PLA Filament | PolyMaker Matte White PLA (LED lens - REQUIRED) | Buy on Amazon |
- Files: Available in
hardware/3d-printed-case/ - Enclosure: Matte Black PLA recommended (or any color)
- LED Lens: Matte White PLA REQUIRED for optimal light diffusion
- Print Time: ~3-4 hours total
- Cost: ~$2 USD material cost (if you have a 3D printer)
- Post-Processing: Heat set insert installation required (soldering iron)
| Component | Description | Amazon Link |
|---|---|---|
| USB-C Cable & Adapter | USB-C cable + power adapter kit | Buy on Amazon |
- Input: 5V via USB-C, 1A minimum
- Power Consumption: ~0.5W average (e-ink refresh), <0.1W standby
- Order Components - Use Amazon links above or source locally
- 3D Print Enclosure - Files in
hardware/3d-printed-case/ - Install PlatformIO - Download PlatformIO IDE
- Clone Repository:
git clone https://github.com/max05210238/CryptoBar.git cd CryptoBar - Compile & Upload Firmware:
pio run -t upload
- Assemble Hardware - Follow Hardware Assembly Guide
- Configure WiFi - Device creates "CryptoBar-XXXXXX" AP on first boot
Estimated Build Time: 2-4 hours (including 3D printing) Estimated Cost: ~$35 USD (with own 3D printer, ~$40 if using print service)
- 📘 Hardware Assembly Guide - Complete build guide from BOM to final assembly
- 📺 Display Guide - UI layout, navigation, screen elements explained
- 🎨 LED Display Guide - LED colors, animations, troubleshooting
- 🔄 OTA Update Guide - Firmware updates and security considerations
- ⚙️ Configuration Guide - WiFi setup, settings options (Coming Soon)
- 🚨 Troubleshooting Guide - Common issues and solutions (Coming Soon)
- 📝 Changelog - Detailed version history (V0.97 → V0.99q)
- 📄 Release Notes - Technical details for each version
- 🔧 Pre-Launch Audit - Documentation review and roadmap
BTC, ETH, BNB, XRP, SOL, TRX, DOGE, ADA, BCH, LINK, XMR, XLM, LTC, AVAX, HBAR, SHIB, TON, UNI, DOT, KAS, FLR
Automatically sorted by market cap at build time. Stablecoins (USDT/USDC) intentionally excluded.
USD, TWD, EUR, GBP, CAD, JPY, KRW, SGD, AUD
Choose your update frequency based on your needs and number of devices:
| Interval | Best For | CoinGecko API Usage | Notes |
|---|---|---|---|
| 1 minute | Active traders, 1-4 devices | ~60 requests/hour per device | ⚡ Real-time tracking |
| 3 minutes ⭐ | 5-8 devices, general use | ~20 requests/hour per device | Recommended - balances freshness and API limits |
| 5 minutes | 9+ devices, battery-friendly | ~12 requests/hour per device | 🔋 Extended uptime |
| 10 minutes | 9+ devices, maximum savings | ~6 requests/hour per device | 🔋🔋 Maximum battery life |
Multi-Device Calculation:
- 1-4 devices @ 1min: 4 devices × 1 req/min = 4 req/min ✅ Safe
- 8 devices @ 3min: 8 devices ÷ 3 min = ~2.7 req/min ✅ Safe
- 10 devices @ 1min: 10 devices × 1 req/min = 10 req/min
⚠️ Approaching limit - 10 devices @ 5min: 10 devices ÷ 5 min = 2 req/min ✅ Safe
Note: CryptoBar includes MAC-based jitter (0-10 second random delay) to distribute API requests and prevent rate limit issues even with multiple devices.
- Partial Refresh - Fast updates, minimal ghosting, battery-friendly
- Full Refresh - Complete screen clear, eliminates ghosting, slower
27 timezones from UTC-12 (Baker Island) to UTC+14 (Kiritimati)
- Auto-detection on first boot
- Manual selection in settings menu
Quick reference for LED colors:
| Color | Meaning | Condition |
|---|---|---|
| 🟢 Green | Price rising | 24h gain > +0.02% |
| 🔴 Red | Price falling | 24h loss < -0.02% |
| 🌈 Rainbow | Party Mode! | 24h gain ≥ +20% 🎉 |
| 🟡 Yellow | API failure | Can't fetch prices |
| 🔵 Blue | Connecting | WiFi connection in progress |
| 🟣 Purple | Configuration | WiFi portal or firmware update mode |
Breathing Animation:
- Static (< 5% change)
- Slow breathing (5-10% change)
- Fast breathing (≥ 10% change)
Full details: LED Display Guide
| Component | Pin Function | GPIO | Notes |
|---|---|---|---|
| E-ink Display | CS (Chip Select) | GPIO 10 | SPI |
| DC (Data/Command) | GPIO 17 | - | |
| RST (Reset) | GPIO 16 | - | |
| BUSY | GPIO 4 | Status input | |
| Rotary Encoder | CLK (Phase A) | GPIO 2 | PCNT-compatible |
| DT (Phase B) | GPIO 1 | PCNT-compatible | |
| SW (Button) | GPIO 21 | Active low | |
| Status LED | NeoPixel Data | GPIO 15 | WS2812B |
Note: GPIO 2/1 specifically chosen for ESP32-S3 PCNT (Pulse Counter) peripheral support.
See Hardware Guide for detailed wiring diagrams.
CryptoBar uses a robust 4-layer fallback system for maximum reliability:
- CoinGecko (Primary) - Aggregated from 500+ exchanges
- CoinPaprika (Fallback 1) - Aggregated from 200+ exchanges
- Kraken (Fallback 2) - Direct exchange data
- Binance (Fallback 3) - Direct exchange data
- CoinGecko (Primary) - Aggregated historical data
- Binance (Fallback 1) - Kline/candlestick data
- Kraken (Fallback 2) - OHLC data
- Primary: open.er-api.com (1,500 requests/month)
- Fallback: fxratesapi.com (unlimited)
| Coin | Real-time Price | Historical Chart | CoinGecko | CoinPaprika | Kraken | Binance |
|---|---|---|---|---|---|---|
| BTC | ✅ | ✅ | ✅ | ✅ | ✅ | ✅ |
| ETH | ✅ | ✅ | ✅ | ✅ | ✅ | ✅ |
| XRP | ✅ | ✅ | ✅ | ✅ | ✅ | ✅ |
| BNB | ✅ | ✅ | ✅ | ✅ | ❌ | ✅ |
| SOL | ✅ | ✅ | ✅ | ✅ | ❌ | ✅ |
| TRX | ✅ | ✅ | ✅ | ✅ | ❌ | ✅ |
| DOGE | ✅ | ✅ | ✅ | ✅ | ❌ | ✅ |
| ADA | ✅ | ✅ | ✅ | ✅ | ❌ | ✅ |
| BCH | ✅ | ✅ | ✅ | ✅ | ❌ | ✅ |
| LINK | ✅ | ✅ | ✅ | ✅ | ❌ | ✅ |
| XMR | ✅ | ✅ | ✅ | ✅ | ❌ | ✅ |
| XLM | ✅ | ✅ | ✅ | ✅ | ❌ | ✅ |
| LTC | ✅ | ✅ | ✅ | ✅ | ❌ | ✅ |
| AVAX | ✅ | ✅ | ✅ | ✅ | ❌ | ✅ |
| HBAR | ✅ | ✅ | ✅ | ✅ | ❌ | ✅ |
| SHIB | ✅ | ✅ | ✅ | ✅ | ❌ | ✅ |
| TON | ✅ | ✅ | ✅ | ✅ | ❌ | ✅ |
| UNI | ✅ | ✅ | ✅ | ✅ | ❌ | ✅ |
| DOT | ✅ | ✅ | ✅ | ✅ | ❌ | ✅ |
| KAS | ✅ | ✅ | ✅ | ✅ | ❌ | ✅ |
| FLR | ✅ | ✅ | ✅ | ❌ | ❌ |
Notes:
- ✅ = Supported | ❌ = Not available |
⚠️ = Limited (CoinGecko only) - FLR Historical Chart: Only available via CoinGecko. If CoinGecko is unavailable, chart will not display.
- Kraken Support: Only BTC, ETH, XRP have Kraken trading pairs.
- All coins support real-time price via CoinGecko and CoinPaprika fallback.
Rate Limit Management:
- MAC-based request jitter (0-10 seconds)
- Recommended 3-minute update interval for multi-device deployments
- Automatic retry on failure
No API Keys Required - All APIs used are free-tier public endpoints.
- ⚡ Non-blocking Network: Menu operations no longer freeze during coin switching
- 📱 Captive Portal Auto-popup: WiFi setup page opens automatically on iOS/Android
- 🪙 Flare (FLR) Support: 21 cryptocurrencies now supported
- 📊 Auto Coin Ordering: Build-time market cap sorting via Python script
- 📶 WiFi Hostname: Device appears as "CryptoBar_XXXX" on router
- 🔧 Multi-API Fallback: CoinGecko → CoinPaprika → CoinCap for coin rankings
- 🎯 VFD Display Support: Retro 16-character VFD displays (PT6302 controller)
- 📺 Dual Display Architecture: Automatic detection of e-ink or VFD displays
- 🔄 NTP-Synced Page Rotation: Multi-device synchronized updates (10-second cycles)
- 🌙 Auto Brightness: Time-based VFD brightness with anti-burn-in protection
- 🔄 Unified WiFi Retry: Infinite retry loop with cooldown screens
- ⚡ WiFi Timing Optimization: Background connection during splash screen
- V0.99r: Critical array bounds bug fix (10-minute interval crash)
- V0.99q: WiFi portal settings fix, independent time refresh
- V0.99p: High-precision price display (14-16 decimals)
- V0.99n: CoinGecko as primary API (better quality)
- V0.99l: Display refresh optimization (95% less flicker)
- V0.99k: Aggregated market data (200+ exchanges)
- V0.99g: Binance API integration (38% faster)
- V0.99f: Multi-currency support (9 currencies)
- V0.99a: Encoder optimization (critical GPIO fix)
See CHANGELOG.md for complete version history.
Requirements:
- PlatformIO
- ESP32-S3 board connected via USB
Compile:
pio runUpload:
pio run -t uploadMonitor Serial Output:
pio device monitorCryptoBar/
├── src/ # Source code (modular architecture)
│ ├── main.cpp # Main application logic
│ ├── app_state.cpp # Global state management
│ ├── app_wifi.cpp # WiFi management
│ ├── app_time.cpp # NTP sync and timezone
│ ├── network.cpp # API fetching (4-layer fallback)
│ ├── ui.cpp # E-ink display rendering
│ ├── led_status.cpp # RGB LED control
│ ├── encoder_pcnt.cpp # Rotary encoder (PCNT)
│ └── ...
├── include/ # Header files
├── docs/ # Documentation
│ ├── guides/ # User guides
│ └── release-notes/ # Version technical details
├── hardware/ # 3D models and schematics
│ └── 3d-printed-case/ # STL files
├── platformio.ini # PlatformIO configuration
└── CHANGELOG.md # Version history
- Modular Design: Functionality split into focused modules (V0.98 refactoring)
- State Management: Centralized global state in
app_state.cpp - Multi-API Resilience: Automatic failover across 4 data sources
- Hardware Abstraction: PCNT peripheral for encoder, GxEPD2 for display
- OTA Support: Dual partition table for safe wireless updates
Contributions are welcome! This project is open-source to benefit the maker community.
- Fork the repository
- Create a feature branch (
git checkout -b feature/amazing-feature) - Commit your changes (
git commit -m 'Add amazing feature') - Push to the branch (
git push origin feature/amazing-feature) - Open a Pull Request
- 📱 Additional API integrations
- 🌐 More cryptocurrency support
- 🎨 Alternative display layouts
- 🔧 Hardware modifications (battery power, different displays)
- 📚 Documentation improvements
- 🌍 Translations
This project is licensed under the MIT License - see LICENSE file for details.
Copyright © 2025 max05210238
You are free to:
- ✅ Use commercially
- ✅ Modify
- ✅ Distribute
- ✅ Private use
Developer: max05210238 AI Development Assistant: Claude (Anthropic)
Hardware:
- ESP32-S3 (Espressif Systems)
- WaveShare 2.9" e-Paper Display
- Bourns PEC11R-S0024 Rotary Encoder (recommended)
Software Libraries:
- GxEPD2 - E-ink display driver
- ArduinoJson - JSON parsing
- Adafruit GFX - Graphics library
- Adafruit NeoPixel - LED control
- 🐛 Bug Reports: GitHub Issues
- 💡 Feature Requests: GitHub Discussions
- 📧 Contact: Via GitHub
CryptoBar is an open-source project built and maintained with passion. If you find this project useful and want to support its continued development, consider making a donation!
💖 Donate via PayPal
Your generous donation helps cover development costs, hardware testing, and keeps this project alive and improving.
Other Ways to Help:
- ⭐ Star this repository - It helps others discover CryptoBar
- 🔧 Contribute code - See Contributing section
- 📝 Improve documentation - Help make guides clearer
- 📸 Share your build - Show off your CryptoBar on social media
- 🐛 Report bugs - Help make CryptoBar better for everyone
Thank you for your support! Every contribution, big or small, helps keep this project growing and improving for the entire maker community.
This device displays cryptocurrency prices for informational purposes only. It is not financial advice. Always do your own research before making investment decisions.
Made with ❤️ for the crypto and maker communities
Star ⭐ this project if you find it useful!