Use Cases

The OWL can be adapted for various weed control and data collection applications.

Vehicle-Mounted Spot Spraying

The primary use case for the OWL is site-specific herbicide application in fallow fields.

Vehicle-mounted OWL

The OWL team designed and assembled a 2m spot spraying boom using two OWLs to control four 12V solenoids each. The boom was mounted on a ute/utility vehicle with:

  • Spray tank in the tray

  • Powered by 12V car battery

  • Indicator lights for each nozzle (for demonstration/testing)

Specifications

Parameter

Details

Notes

Mounting gap

0 cm

Mounted directly to same bar as nozzles, 32cm higher

Forward Speed

6-8 km/h

Image blur/activation time limiting. Moving OWL forward improves speed for large weeds

Solenoids

Goyen 3QH/3662 with Teejet body

Many alternatives exist - see GitHub Issue #2

Spray tips

Teejet TP4003E-SS

40 degree, flat fan nozzles, stainless steel

Strainer

TeeJet 50 mesh

Protects spray tip from clogging/damage

Pump/tank

Northstar 12V 60L ATV Sprayer

8.3 LPM 12V pump, 60L capacity, tray mounted

Robot-Mounted Spot Spraying

A second system was developed for the University of Sydney’s Digifarm robot, the Agerris Digital Farm Hand.

Robot-mounted OWL

Key differences:

  • Powered by 24V robot system

  • Uses 24-12V DC/DC converter

  • In frequent use for site-specific weed control in trial areas

Image Data Collection

The OWL can act as a high-quality image data collection tool for developing training datasets in realistic agricultural environments.

Collection Methods

Method

Code

Example

Whole image

whole

Whole image

Crop to bounding box

bbox

Bounding box

Crop to square around weed centre

square

Square crop

Deactivated (default)

None

No images saved

Configuration

Settings are updated in config.ini:

[DataCollection]
sample_images = True
sample_method = whole
sample_frequency = 30
save_directory = /media/owl/SanDisk
disable_detection = False

Parameter

Description

sample_images

Enable/disable collection (True/False)

sample_method

whole, bbox, square, or None

sample_frequency

Save every N frames

save_directory

USB drive path for saving images

disable_detection

Set True for data collection only (improves frame rate)

Storage Warning

Do not leave sampling on for long periods or the SD card/USB drive will fill up and stop working.

Other Applications

The OWL relay outputs can control any 12V device, enabling:

  • Targeted tillage - Mechanical weed control

  • Spot flaming - Thermal weed control

  • Variable rate application - Fertiliser or other inputs

  • Custom automation - Any detection-triggered action

Share Your Build

As more OWLs are built and fallow weed control systems developed, we would love to share the results!

  • Post in the OWL Community

  • Share images of your finished systems

  • Describe your specific application and setup

Next Steps