Document Type

Thesis - Open Access

Award Date

2024

Degree Name

Master of Science (MS)

Department / School

Agronomy, Horticulture, and Plant Science

First Advisor

Ali Mirzakhani Nafchi

Keywords

Variable Rate, data log, Anti-slip, Encoder, GPS

Abstract

The need to optimize resource utilization while increasing crop productivity is paramount. This research proposes a Low-cost Retrofittable Variable Rate Applicator Controller (VRAC) that aims to leverage the adoption of Variable Rate Technologies. The controller operates via the Raspberry Pi platform, a Global Positioning System (GPS), a stepper motor drive, and an anti-slip wheel encoder. The VRAC allows precise, on-the-fly control of variable-rate application of farming inputs. It utilizes GPS with 10 cm accuracy to pinpoint geographic coordinates in real-time. A wheel encoder measures traveling speed with a slip-resistant wheel design for precise RPM readings. The Raspberry processes the data, enabling dynamic adjustments of variability based on predefined maps, while the motor driver controls the motor’s RPM. The VRAC is designed to be plug-and-play and user-friendly accessible for a wider range of farming practices, including seeding rate, dry fertilizer, and liquid fertilizer application. Additionally, data are logging from various field sensors. The controller exhibits an average accuracy of 0.864 s for rate changes from 267 to 45, 45 to 241, 241 to 128, 128 to 218, and 218 to 160 kg/ha at speeds of 8, 11, 16, 19, 24, and 32 km/h. It has an average Coefficient of Variation of 4.59 and an Accuracy of 97.17% for seeding discharge. Its cost-effectiveness and retrofit capability offer an option to a broader range of farmers, democratizing precision agriculture and promoting sustainable practices.

Library of Congress Subject Headings

Precision farming.
Agricultural innovations.
Fertilizers -- Application.

Publisher

South Dakota State University

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Rights Statement

In Copyright