Node-RED Contrib Waveshare DA-AD HAT

Custom Node-RED nodes for the Waveshare DA-AD HAT with working drivers. This package provides reliable control of the Digital-to-Analog Converter (DAC) and Analog-to-Digital Converter (ADC) functionality through proven Python drivers.

Features

DAC Node (waveshare-da)

• Dual Port Support: Control both DAC channels (Port 0 and Port 1)
• 16-bit Resolution: Full 0-65535 value range
• Auto-update: Configurable automatic output updates
• Input Override: Override configured values via message payload
• Error Handling: Comprehensive error reporting and validation

ADC Node (waveshare-ad)

• 8 Single-Ended Channels: Read from any of the 8 ADC channels (0-7)
• Configurable Gain: 1x to 64x gain settings for signal amplification
• Flexible Data Rates: 2.5 to 30,000 samples per second (SPS)
• Input Buffering: Optional high-impedance buffer (~100 MΩ) for sensitive sensors
• Auto-read: Configurable automatic reading intervals
• Real-time Monitoring: Ideal for continuous sensor monitoring

Installation

Prerequisites

• Node-RED (version 2.0.0 or higher)
• Raspberry Pi (or compatible single-board computer)
• Python 3 with required packages

Install Python Dependencies

# Install system packages
sudo apt-get update
sudo apt-get install python3-pip python3-dev

# Install Python packages
pip3 install spidev RPi.GPIO

Install Node-RED Package

# Navigate to your Node-RED user directory
cd ~/.node-red

# Install the package
npm install node-red-contrib-waveshare-da-ad-hat

Restart Node-RED

After installation, restart Node-RED to load the new nodes.

Hardware Setup

Waveshare DA-AD HAT Connection

1. Power: Connect the HAT to your Raspberry Pi
2. SPI Interface: Ensure SPI is enabled in raspi-config
3. GPIO Pins: The HAT uses specific GPIO pins for CS, RST, and DRDY

Enable SPI on Raspberry Pi

# Enable SPI interface
sudo raspi-config

# Navigate to: Interface Options > SPI > Enable
# Reboot after enabling
sudo reboot

# Verify SPI is enabled
ls /dev/spidev*

Usage

DAC Node Configuration

Basic Setup

1. Drag the "Waveshare DA" node to your flow
2. Configure the DAC port (0 or 1)
3. Set the default output value (0-65535)
4. Optionally enable auto-update with custom interval

Message Input

{
  "payload": {
    "port": 0,
    "value": 32768
  }
}

Output

{
  "payload": {
    "port": 0,
    "value": 32768,
    "success": true,
    "timestamp": 1703123456789
  }
}

ADC Node Configuration

Basic Setup

1. Drag the "Waveshare AD" node to your flow
2. Select the ADC channel (0-7)
3. Configure gain, buffering, and data rate
4. Optionally enable auto-read with custom interval

Message Input

{
  "payload": {
    "channel": 2,
    "gain": 16,
    "buffered": true,
    "dataRate": 500
  }
}

Data Rate Options:

• 2.5-30 SPS: Slow, high precision measurements
• 50-500 SPS: Medium speed, general purpose
• 1000-30000 SPS: Fast, real-time monitoring

Output

{
  "payload": {
    "channel": 2,
    "gain": 16,
    "buffered": true,
    "dataRate": 500,
    "reading": 12345,
    "rawOutput": "AIN2 reading: 12345",
    "success": true,
    "timestamp": 1703123456789
  }
}

Pool Management System Integration

This package is specifically designed for pool management applications:

Power Supply Control (DAC)

• Port 0: Control variable power supply voltage
• Port 1: Control current limiting or secondary power rail
• Auto-update: Maintain consistent power levels

Sensor Monitoring (ADC)

• Current Sensing: Hall effect sensors for power monitoring
• Voltage Monitoring: Resistor divider bridges for voltage measurement
• pH Sensing: Interface with pH sensors for water quality
• Temperature: Monitor water and equipment temperature
• Auto-read: Continuous monitoring with configurable intervals

Development

Project Structure

├── src/                    # TypeScript source files
│   ├── nodes/             # Node implementations
│   └── index.ts           # Main entry point
├── nodes/                  # HTML editor files
├── python/                 # Python driver scripts
├── types/                  # TypeScript type definitions
├── lib/                    # Compiled JavaScript (generated)
└── package.json           # Package configuration

Build Commands

# Install dependencies
npm install

# Build the project
npm run build

# Watch mode for development
npm run dev

# Clean build artifacts
npm run clean

TypeScript Development

The project uses TypeScript with strict type checking:

• Full type safety for Node-RED interfaces
• Proper error handling and validation
• Modern ES2020 features
• Source maps for debugging

Troubleshooting

Common Issues

SPI Permission Denied

# Add user to spi group
sudo usermod -a -G spi $USER
# Log out and back in, or reboot

Python Script Not Found

• Ensure Python scripts are in the python/ directory
• Check file permissions: chmod +x python/*.py
• Verify Python 3 is available: python3 --version

GPIO Access Denied

# Add user to gpio group
sudo usermod -a -G gpio $USER
# Log out and back in, or reboot

Debug Mode

Enable Node-RED debug mode to see detailed error messages:

# Start Node-RED with debug logging
node-red --verbose

Contributing

1. Fork the repository
2. Create a feature branch: git checkout -b feature-name
3. Make your changes
4. Test thoroughly
5. Submit a pull request

License

MIT License - see LICENSE file for details.

Support

• Issues: GitHub Issues
• Discussions: GitHub Discussions

Acknowledgments

• Waveshare for the DA-AD HAT hardware
• Node-RED community for the excellent framework
• Python community for the reliable hardware interface libraries

Note: This package includes working Python drivers that have been tested and proven reliable. The Node-RED nodes provide a user-friendly interface while maintaining the performance and reliability of the underlying hardware drivers.