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

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- 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

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- 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

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

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``bash

Install system packages

sudo apt-get update
sudo apt-get install python3-pip python3-dev

Install Python packages

pip3 install spidev RPi.GPIO
`

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`bash

Navigate to your Node-RED user directory

cd ~/.node-red

Install the package

npm install node-red-contrib-waveshare-da-ad-hat
`

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

Hardware Setup

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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

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`bash

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

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#### 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
`json
{
"payload": {
"port": 0,
"value": 32768
}
}
`

#### Output
`json
{
"payload": {
"port": 0,
"value": 32768,
"success": true,
"timestamp": 1703123456789
}
}
`

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#### 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
`json
{
"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
`json
{
"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:

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

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- 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

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`
├── 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
`

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`bash

Install dependencies

npm install

Build the project

npm run build

Watch mode for development

npm run dev

Clean build artifacts

npm run clean
`

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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

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#### SPI Permission Denied
`bash


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
`bash


Add user to gpio group

sudo usermod -a -G gpio $USER

Log out and back in, or reboot

`

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

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.