Crypto & Stock Price Display for M5StickC Plus2

A comprehensive cryptocurrency and stock price ticker that displays real-time prices on the M5StickC Plus2. Features intelligent market hours detection, price movement indicators, Home Assistant integration via MQTT, and customizable brightness control.

Features

Multi-Asset Display: BTC, ETH, XRP (CAD) + MSFT Stock (USD)
Home Assistant Integration: Auto-discovery via MQTT with real-time price updates
Smart Market Hours: Stock API only fetches during trading hours (9:05 AM - 4:05 PM ET) with automatic EST/EDT switching
Price Movement Indicators: Green up arrows ↗️ and red down arrows ↘️
5-Level Brightness Control: 20%, 40%, 60%, 80%, 100% (Button A to cycle)
Efficient API Usage: 5-minute update intervals to preserve battery and API quotas
NTP Time Synchronization: Automatic Eastern Time (EST/EDT) with DST switching
Market Status Display: Shows "Market Closed" when appropriate while preserving last known prices
Professional Display: Centered icons, dynamic positioning, smooth transitions

Hardware Requirements

M5StickC Plus2 ESP32-PICO-V3-02 Mini IoT Development Kit
- Purchase Link
- Chip: ESP32-PICO-V3-02 SiP (8MB Flash, 2MB PSRAM)
- Display: 1.14" TFT LCD

API & Service Requirements

CoinMarketCap API (Cryptocurrency Data)

Create account at CoinMarketCap API
Free tier: 10,000 calls/month (sufficient for this project)

Financial Modeling Prep API (Stock Data)

Create account at Financial Modeling Prep
Free tier available

MQTT Broker (Home Assistant Integration)

Mosquitto MQTT Broker running on Home Assistant or standalone
Can use Home Assistant's built-in Mosquitto add-on
Default port: 1883

Installation & Setup

Clone Repository:

git clone https://github.com/sfrechette/crypto-price-cad.git
cd crypto-price-cad

Configure API Keys & MQTT:
```
cp secrets_template.h src/secrets.h
# Edit src/secrets.h with your credentials
```
Required configuration in secrets.h:
- WiFi credentials (SSID, password)
- CoinMarketCap API key
- Financial Modeling Prep API key
- MQTT broker IP address (your Home Assistant IP)
- MQTT credentials (if authentication enabled)
Build & Upload:
```
pio run --target upload
```
Home Assistant Setup:

The device automatically publishes MQTT discovery configs. After upload:
- Sensors appear automatically under Settings → Devices & Services → MQTT
- Device name: "Crypto Price Display"
- Entities created: Bitcoin Price, Ethereum Price, XRP Price, Microsoft Price

Architecture Overview

Project Structure

crypto-price-cad/
├── src/
│   ├── main.cpp              # Main application logic & setup
│   ├── api_client.cpp/.h     # Network & API handling
│   ├── crypto_display.cpp/.h # Display management
│   ├── mqtt_client.cpp/.h    # Home Assistant MQTT integration
│   ├── config.h              # Configuration constants
│   ├── secrets.h             # API keys, WiFi & MQTT credentials
│   └── icons.h               # Asset icons & arrows (RGB565)
├── include/                  # Original PNG icons
├── platformio.ini            # PlatformIO configuration
├── SECURITY_SETUP.md         # Credential security guide
└── README.md                 # This file

MQTT Topic Structure

m5crypto/
├── status                    # Device availability (online/offline)
├── btc/state                 # Bitcoin price & trend
├── eth/state                 # Ethereum price & trend
├── xrp/state                 # XRP price & trend
└── msft/state                # Microsoft stock price & trend

Home Assistant Discovery Topics

homeassistant/sensor/m5crypto_btc/config
homeassistant/sensor/m5crypto_eth/config
homeassistant/sensor/m5crypto_xrp/config
homeassistant/sensor/m5crypto_msft/config

Code Execution Flow

Startup Sequence (setup())

Arduino Framework → main() → setup()
├── 1. Serial.begin(115200)           # Debug output
├── 2. M5.begin()                     # Initialize M5StickC Plus2
├── 3. display.begin()                # Setup display settings
├── 4. Set brightness (20% default)   # M5Unified API brightness control
├── 5. apiClient.connectWiFi()        # Connect to WiFi
├── 6. setupTime()                    # NTP time sync (Eastern Time)
├── 7. mqttClient.begin()             # Connect to MQTT broker
├── 8. publishDiscoveryConfigs()      # Register entities with Home Assistant
├── 9. fetchAndUpdateData()           # Initial data fetch
├── 10. mqttClient.publishPrices()    # Send initial prices to HA
└── 11. Initialize timers             # Setup update intervals

Main Loop (loop()) - Repeats every 50ms

loop() [Continuous Execution]
├── M5.update()                       # Check button presses
├── mqttClient.loop()                 # Maintain MQTT connection
├── Button A pressed?                 # Brightness control
│   └── cycleBrightness()             # Cycle through 5 levels
├── 5 minutes passed?                 # API update check
│   └── fetchAndUpdateData()
│       ├── fetchCryptoData()         # Always fetch crypto (24/7)
│       ├── isMarketOpen()?           # Market hours check
│       │   ├── fetchStockData()      # Fetch if market open
│       │   └── Skip if market closed # Save API calls & battery
│       └── mqttClient.publishPrices()# Send to Home Assistant
├── 10 seconds passed?                # Display rotation
│   └── Switch currentAssetIndex      # BTC→ETH→XRP→MSFT
├── displayAsset()                    # Draw current asset
│   ├── Calculate positioning         # Dynamic centering
│   ├── displayIcon()                 # Draw asset icon
│   ├── Draw asset name & price       # Text rendering
│   └── displayPriceArrow()           # Price movement indicator
└── delay(50ms)                       # CPU throttling

API & MQTT Data Flow

fetchAndUpdateData()
├── Crypto API Flow (24/7):
│   ├── HTTPSClient → api.coinmarketcap.com
│   ├── JSON Response → parseCryptoJsonResponse()
│   └── Update BTC, ETH, XRP prices
├── Stock API Flow (Market Hours Only):
│   ├── isMarketOpen() → Check Eastern Time & weekday
│   ├── HTTPSClient → financialmodelingprep.com
│   ├── JSON Response → parseStockJsonResponse()
│   └── Update MSFT price with timestamp
└── MQTT Publishing:
    ├── mqttClient.publishPrices()
    ├── Build JSON payload (price, trend, updated)
    └── Publish to m5crypto/{symbol}/state

MQTT Message Flow

Device Startup:
├── Connect to MQTT Broker
├── Set Last Will: m5crypto/status → "offline"
├── Publish: m5crypto/status → "online"
└── Publish Discovery Configs (4 sensors)

Every 5 Minutes:
├── Fetch prices from APIs
├── For each asset:
│   └── Publish JSON to m5crypto/{symbol}/state
│       {"price": 63245.67, "trend": "up", "updated": "14:30:45"}
└── Home Assistant auto-updates entities

On Disconnect:
└── Broker publishes Last Will: m5crypto/status → "offline"

Display Rendering Flow

displayAsset(asset)
├── Calculate Layout:
│   ├── Icon position (centered with text)
│   ├── Text width measurement
│   └── Price + arrow positioning
├── Render Components:
│   ├── Asset icon (24x24 RGB565)
│   ├── Asset name (white text)
│   ├── Price value (yellow text)
│   └── Movement arrow (green↗️/red↘️)
└── Optimize Updates:
    ├── Only redraw changed elements
    └── Prevent screen flashing

Visual Flow Diagram

flowchart TD
    A[Program Start] --> B[setup]
    B --> C[Initialize M5StickC]
    B --> D[Connect WiFi]
    B --> E[Setup NTP Time]
    B --> F[Connect MQTT Broker]
    F --> G[Publish HA Discovery]
    G --> H[Initial Data Fetch]
    H --> I[Publish to MQTT]
    I --> J[loop]
    
    J --> K{Button Pressed?}
    K -->|Yes| L[cycleBrightness]
    L --> J
    K -->|No| M[mqttClient.loop]
    M --> N{Time for API Update?}
    
    N -->|Yes| O[fetchAndUpdateData]
    O --> P[fetchCryptoData]
    O --> Q{Market Open?}
    Q -->|Yes| R[fetchStockData]
    Q -->|No| S[Skip Stock API]
    R --> T[Publish Prices to MQTT]
    S --> T
    P --> T
    T --> U[Display Update]
    
    N -->|No| V{Time for Display Switch?}
    V -->|Yes| W[Switch Asset Index]
    W --> X[displayAsset]
    V -->|No| X
    
    X --> Y[Draw Icon]
    X --> Z[Draw Text]
    X --> AA[Draw Price Arrow]
    AA --> AB[delay 50ms]
    AB --> J
    
    style A fill:#ff9999
    style J fill:#99ccff
    style O fill:#99ff99
    style T fill:#ffcc66
    style X fill:#ffcc99

Copy the above Mermaid code to mermaid.live for an interactive diagram

Home Assistant Integration

Auto-Discovered Entities

After device startup, the following sensors are created automatically:

Entity ID	Name	Unit	Icon
`sensor.m5crypto_btc_price`	Bitcoin Price	CAD	mdi:bitcoin
`sensor.m5crypto_eth_price`	Ethereum Price	CAD	mdi:ethereum
`sensor.m5crypto_xrp_price`	XRP Price	CAD	mdi:alpha-x-circle
`sensor.m5crypto_msft_price`	Microsoft Price	USD	mdi:microsoft

Sensor Attributes

Each sensor includes additional attributes:

trend: "up", "down", or "unknown"
updated: Last update timestamp

Example Dashboard Card

type: entities
title: Crypto Prices
entities:
  - entity: sensor.m5crypto_btc_price
    name: Bitcoin
  - entity: sensor.m5crypto_eth_price
    name: Ethereum
  - entity: sensor.m5crypto_xrp_price
    name: XRP
  - entity: sensor.m5crypto_msft_price
    name: Microsoft

Example Automation

automation:
  - alias: "Notify on Bitcoin Price Change"
    trigger:
      - platform: state
        entity_id: sensor.m5crypto_btc_price
    condition:
      - condition: template
        value_template: "{{ trigger.to_state.attributes.trend == 'up' }}"
    action:
      - service: notify.mobile_app
        data:
          title: "Bitcoin Going Up! 📈"
          message: "BTC is now ${{ states('sensor.m5crypto_btc_price') }} CAD"

XRP Icon Note

The XRP sensor uses mdi:alpha-x-circle since Material Design Icons don't include a native XRP logo. For the actual XRP logo, install Simple Icons via HACS and change the icon to si:xrp in the entity settings.

Key Function Groups

API & Network Functions

APIClient::connectWiFi() - WiFi connection with timeout
APIClient::fetchCryptoData() - CoinMarketCap API calls
APIClient::fetchStockData() - Financial Modeling Prep API calls
APIClient::parseJsonResponse() - JSON data parsing
isMarketOpen() - Eastern Time market hours detection with EST/EDT auto-switching

Display Functions

CryptoDisplay::displayAsset() - Main rendering function
CryptoDisplay::displayIcon() - Asset icon rendering
CryptoDisplay::displayPriceArrow() - Price movement indicators
CryptoDisplay::formatPrice() - Price formatting with commas

MQTT Functions

MQTTClient::begin() - Connect to MQTT broker with LWT
MQTTClient::publishDiscoveryConfigs() - Register entities with Home Assistant
MQTTClient::publishPrices() - Send current prices to all topics
MQTTClient::publishAvailability() - Device online/offline status
MQTTClient::loop() - Maintain connection (call in main loop)

Utility Functions

setupTime() - NTP synchronization
cycleBrightness() - Brightness control
fetchAndUpdateData() - Main update coordinator

Latest Features & Improvements

Home Assistant Integration (v2.2)

MQTT Auto-Discovery: Entities automatically appear in Home Assistant
Real-Time Updates: Prices published every 5 minutes via MQTT
Device Grouping: All sensors grouped under "Crypto Price Display" device
Availability Tracking: Online/offline status with Last Will and Testament
Trend Attributes: Price direction (up/down) available for automations

Performance Optimizations (v2.1)

50% Faster Button Response: Loop delay reduced from 100ms to 50ms
2 Seconds Faster Startup: WiFi network scan disabled by default
Memory Optimization: Constants moved to flash memory
M5Unified Library: Universal M5Stack library for better device compatibility
Cleaner Code: Price tracking centralized in API client layer

Eastern Time Zone Support (v2.1)

Automatic EST/EDT Switching: Proper US Eastern Time handling
No More Midnight API Calls: Fixed timezone bug
Accurate Market Hours: 9:05 AM - 4:05 PM ET with DST adjustments

Smart Market Status Display (v2.1)

"Market Closed" Message: Clear status when stock market is closed
Price Persistence: Last known stock price remains visible
Arrow Preservation: Price movement indicators persist through market close

Performance Optimizations

Battery Life

5-minute API intervals instead of continuous fetching
Market hours detection prevents unnecessary stock API calls
Partial screen updates to minimize display power consumption
50ms loop delay balances CPU usage with responsive button control

API Efficiency

Smart caching - displays last known prices during API failures
Rate limit compliance - stays within free tier quotas
Error handling - graceful degradation on network issues

Memory Management

PROGMEM storage for icons (saves RAM)
StaticJsonDocument for MQTT payloads (stack-based, efficient)
Efficient string handling to prevent memory fragmentation
Constexpr constants stored in flash memory instead of RAM

Network Efficiency

MQTT Keep-Alive maintains persistent broker connection
Retained Messages for discovery configs (survive broker restart)
Last Will and Testament for reliable offline detection

Configuration Options

Update Intervals (config.h)

#define API_UPDATE_INTERVAL 300000    // 5 minutes
#define DISPLAY_DURATION 10000        // 10 seconds per asset

Brightness Levels (main.cpp)

constexpr uint8_t BRIGHTNESS_LEVELS[] = {51, 102, 153, 204, 255}; // 5 levels: 20-100%
uint8_t currentBrightnessIndex = 0;                                 // Default: 20%

Market Hours (main.cpp)

int marketOpenMinutes = 9 * 60 + 5;   // 9:05 AM ET
int marketCloseMinutes = 16 * 60 + 5;  // 4:05 PM ET

MQTT Settings (secrets.h)

#define MQTT_BROKER "192.168.1.100"   // Home Assistant IP
#define MQTT_PORT 1883                 // Default Mosquitto port
#define MQTT_USER "mqtt_user"          // Optional authentication
#define MQTT_PASSWORD "mqtt_pass"      // Optional authentication
#define MQTT_CLIENT_ID "m5crypto"      // Unique client ID
#define MQTT_TOPIC_PREFIX "m5crypto"   // Base topic for messages

Development Tools

Code Analysis Tools

Doxygen + Graphviz - Generate call graphs from comments
VS Code + C/C++ Extension - Call hierarchy viewer
Mermaid.js - Flowchart visualization
PlatformIO - Build system and debugging

Debugging

# Serial monitor
pio device monitor --baud 115200

# Build with debug info
pio run -e debug

# Upload and monitor
pio run --target upload && pio device monitor

MQTT Debugging

# Monitor all m5crypto topics
mosquitto_sub -h YOUR_HA_IP -u USER -P PASS -t "m5crypto/#" -v

# Monitor Home Assistant discovery
mosquitto_sub -h YOUR_HA_IP -u USER -P PASS -t "homeassistant/sensor/m5crypto_#/config" -v

Monitoring & Logs

Serial Output Examples

Startup with MQTT:

=== Cryptocurrency Price Display v2.2 (M5StickC Plus2) ===
Initial brightness set to: 51/255 (20%)
WiFi connected to: YourNetwork
Time synchronized: 2024-09-25 14:30:45 ET
MQTT: Connecting to broker 192.168.1.100:1883
MQTT: Connected successfully!
MQTT: Published availability: online
MQTT: Publishing Home Assistant discovery configs...
MQTT: Discovery BTC -> OK
MQTT: Discovery ETH -> OK
MQTT: Discovery XRP -> OK
MQTT: Discovery MSFT -> OK

During Market Hours:

Current time: 14:30 ET, Market OPEN
Successfully fetched crypto data:
  BTC: $63,245.67 CAD (UP)
  ETH: $3,456.78 CAD (DOWN)
  XRP: $0.89 CAD (UP)
Successfully fetched stock data (market open): MSFT: $425.67 USD (UP)
MQTT: Publishing price updates...
MQTT: BTC $63245.67 CAD -> OK
MQTT: ETH $3456.78 CAD -> OK
MQTT: XRP $0.89 CAD -> OK
MQTT: MSFT $425.67 USD -> OK

After Market Close:

Current time: 16:06 ET, Market CLOSED
Market closed - displaying last known price: MSFT: $425.67 USD

Troubleshooting

Common Issues

WiFi Connection Failed - Check credentials in secrets.h
API Errors - Verify API keys and quotas
Time Sync Issues - Check NTP server accessibility
Display Issues - Verify M5StickC Plus2 connection
MQTT Connection Failed - Check broker IP, port, and credentials
Entities Not Appearing in HA - Verify MQTT integration is configured
Stock API Fetching at Wrong Times - Ensure timezone shows "ET" in logs
MSFT Showing Blank/Zero - Normal when "Market Closed" message appears

MQTT Troubleshooting

Verify broker is running:
```
systemctl status mosquitto
```

Test connection manually:

mosquitto_pub -h YOUR_HA_IP -u USER -P PASS -t "test" -m "hello"

Check HA MQTT integration: Settings → Devices & Services → MQTT
Common MQTT errors:
- MQTT_CONNECT_BAD_CREDENTIALS - Wrong username/password
- MQTT_CONNECTION_TIMEOUT - Wrong IP or firewall blocking
- MQTT_CONNECT_UNAUTHORIZED - User not authorized

Debug Steps

Enable serial monitor for detailed logs
Check WiFi signal strength
Verify API responses in serial output
Monitor MQTT topics with mosquitto_sub
Check Home Assistant logs for MQTT errors

License

This project is open source. See the LICENSE file for details.

Contributing

Fork the repository
Create a feature branch
Make your changes
Add tests if applicable
Submit a pull request

Support

Hardware Issues: M5Stack Community
API Issues: Check respective API documentation
MQTT Issues: Mosquitto Documentation
Home Assistant: HA Community
Code Issues: Create an issue in this repository

Name		Name	Last commit message	Last commit date
Latest commit History 22 Commits
.vscode		.vscode
include		include
lib		lib
src		src
test		test
.gitignore		.gitignore
LICENSE		LICENSE
README.md		README.md
SECURITY_SETUP.md		SECURITY_SETUP.md
crypto-price-cad.jpeg		crypto-price-cad.jpeg
platformio.ini		platformio.ini
secrets_template.h		secrets_template.h

License

sfrechette/crypto-price-cad

Folders and files

Latest commit

History

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Crypto & Stock Price Display for M5StickC Plus2

Features

Hardware Requirements

API & Service Requirements

CoinMarketCap API (Cryptocurrency Data)

Financial Modeling Prep API (Stock Data)

MQTT Broker (Home Assistant Integration)

Installation & Setup

Architecture Overview

Project Structure

MQTT Topic Structure

Home Assistant Discovery Topics

Code Execution Flow

Startup Sequence (setup())

Main Loop (loop()) - Repeats every 50ms

API & MQTT Data Flow

MQTT Message Flow

Display Rendering Flow

Visual Flow Diagram

Home Assistant Integration

Auto-Discovered Entities

Sensor Attributes

Example Dashboard Card

Example Automation

XRP Icon Note

Key Function Groups

API & Network Functions

Display Functions

MQTT Functions

Utility Functions

Latest Features & Improvements

Home Assistant Integration (v2.2)

Performance Optimizations (v2.1)

Eastern Time Zone Support (v2.1)

Smart Market Status Display (v2.1)

Performance Optimizations

Battery Life

API Efficiency

Memory Management

Network Efficiency

Configuration Options

Update Intervals (config.h)

Brightness Levels (main.cpp)

Market Hours (main.cpp)

MQTT Settings (secrets.h)

Development Tools

Code Analysis Tools

Debugging

MQTT Debugging

Monitoring & Logs

Serial Output Examples

Troubleshooting

Common Issues

MQTT Troubleshooting

Debug Steps

License

Contributing

Support

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