ORCID

Abstract

Accurate measurement of plant microclimate is essential for understanding how local environmental conditions influence plant growth and response. In many experimental setups, environmental monitoring is performed using a single measurement point, which may fail to capture spatial variability across a plant array. This thesis presents the design, validation, and deployment of a compact distributed sensing system, referred to as C.A.M.E.R.A. (Crop Autonomous Micro-Environment Recording Array), developed to measure plant microclimate conditions at multiple locations simultaneously.The system integrates air temperature and relative humidity sensing using the SHT85, multi-point soil temperature measurement using DS18B20 probes, and relative light monitoring using the SEN0390 sensor. These components are combined within a compact IoT node based on the Arduino Nano ESP32, incorporating local data logging, real-time clock functionality, and wireless communication. A key feature of the design is the canopy-level sensing arrangement and compact Stevenson-style radiation shield, which improves the reliability of air measurements by reducing the influence of solar loading and enclosure heating. The main advance of this work is the integration of plant-level canopy sensing (temperature, light and humidity), four soil-temperature probes with one per pot across a four-pot plant group, local data storage, wireless monitoring, and staged validation into a compact node architecture that can be repeated across multiple plant groups without substantially disturbing the experimental layout.A staged validation methodology was implemented, including sensor comparison tests, controlled indoor multi-device evaluation, long-term greenhouse deployment, and comparison against a UKAS-calibrated reference instrument. Results show that the selected air sensor provides high consistency, with typical agreement within approximately ±0.15–0.2 °C relative to the calibrated reference. Soil temperature measurements were stable and repeatable, although a consistent offset was observed, which may reflect probe placement, contact conditions, or differences between the probe-based measurement and the external comparison method. Light sensors demonstrated good agreement in relative trend monitoring but were not suitable for absolute radiation measurement. The results indicate that, within the tested conditions, a compact, low-cost distributed sensing platform can provide a practical and reliable basis for spatially resolved plant microclimate monitoring.

Awarding Institution(s)

University of Plymouth

Supervisor

Anne Plessis, Simon Ussher, Jake Shaw-Sutton

Document Type

Thesis

Publication Date

2026

Embargo Period

2026-10-05

Deposit Date

October 2026

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