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dAISy Catcher

The dAISy catcher is a plug-and-play AIS receiver device from Wegmatt. When properly configured, it provides output compatible with AIS-catcher with additional metadata including timestamps, frequency offset, and signal levels. The device connects via serial port (either HAT or USB connection).

Overview

The dAISy catcher outputs NMEA AIS messages over a serial connection (default format, but other formats are available). It can be configured in AIS-catcher as a serial device and connected either via the HAT interface (GPIO serial port) or USB, depending on your requirements. AIS-catcher's functionality to send commands to serial devices at startup allows you to configure the dAISy catcher directly from the AIS-catcher user interface.

Setup and Requirements

The first step is to physically connect the dAISy catcher to your device. Below are quick instructions for both connection methods.

Connection Methods

Raspberry Pi with HAT: Connect via GPIO serial port. The port varies by Raspberry Pi model (e.g., /dev/serial0 on Raspberry Pi 4). Installation follows the dAISy HAT setup guide.

USB Connection: Plug and play - simply connect via USB.

Device paths by operating system:

  • Linux: /dev/serial/by-id/usb-...
  • Windows: COM3, COM4, etc.
  • macOS: /dev/tty.usbserial-...

Important: The dAISy catcher requires a baud rate of 115200 (different from the standard dAISy HAT).

Web Control Configuration

For users running AIS-catcher with the Visual Web Control interface (available for Linux and Docker), you can configure the dAISy catcher through the web interface:

  1. Access the Visual Web Control at http://your-device:8110 (default credentials: admin/admin)
  2. Navigate to the Input section
  3. In the Device Type dropdown, select SERIAL
  4. For the Port field:
  5. Click the search icon (magnifying glass) next to the Port field
  6. Select the appropriate serial port from the list (e.g., /dev/serial0 for HAT on Raspberry Pi 4 or /dev/serial/by-id/... for USB)
  7. Set the Baud Rate to 115200
  8. In the Init Sequence field, enter co2,v

Web Control Configuration for dAISy Catcher

  1. Click Save and then navigate to the Control section to restart AIS-catcher for the changes to take effect

This provides a user-friendly alternative to command-line configuration, especially for beginners.

Command Line Configuration

Using HAT Connection (GPIO Serial)

On Raspberry Pi, the dAISy catcher connected via HAT uses the GPIO serial port. The port path varies by model (e.g., /dev/serial0 on Raspberry Pi 4):

AIS-catcher -e 115200 /dev/serial0 -ge init_seq co2,v

Using USB Connection

When connected via USB, use the device by-id path for a persistent connection:

ls /dev/serial/by-id/
AIS-catcher -e 115200 /dev/serial/by-id/usb-... -ge init_seq co2,v

Initialization Sequence

The init_seq parameter co2,v enables:

  • Signal level information in the output
  • Frequency offset reporting

This provides additional diagnostic information that can be useful for monitoring reception quality.

Example with Output Options

To run the dAISy catcher with JSON output and signal quality information:

AIS-catcher -e 115200 /dev/serial0 -ge init_seq co2,v -o 5

Debugging

To view the raw NMEA data being received from the device:

AIS-catcher -e 115200 /dev/serial0 -ge print on

JSON Configuration

The dAISy catcher can also be configured using JSON:

{
  "serial": {
    "port": "/dev/serial0",
    "baudrate": 115200,
    "init_seq": "co2,v"
  }
}

For USB connection:

{
  "serial": {
    "port": "/dev/serial/by-id/usb-...",
    "baudrate": 115200,
    "init_seq": "co2,v"
  }
}

Settings Reference

Setting Type Value Description
baudrate integer 115200 Serial port speed (required)
port string /dev/serial0 or /dev/serial/by-id/... Serial port device path
init_seq string co2,v Initialization commands (enables signal level and frequency offset)
print boolean on / off Enable debug printing of received data

Additional Resources