Date of Award
Bachelor of Science
IoT, smart, garden, digital, cloud, internet of things, tech, computer
Home gardeners are faced with yearly challenges due to spring frosts harming young plants. This is frequently mitigated by covering crops with frost blankets, but only on nights when a frost is predicted. In areas with less predictable climate, an unexpected frost can kill vulnerable plants, reducing the amount of food produced. A system is proposed and designed here to use internet of things (IoT) technology to enable a small weather station in the home garden to report current climate data and predict frosts, then alert the gardener in time for them to cover their plants.
The system as designed consists of an IoT endpoint, powered by a microcontroller in a watertight housing and connected to a weatherproof temperature and humidity sensor, as well as cloud services configured to collect and analyze weather data, and finally an iOS app for gardeners to monitor the conditions in their gardens and receive push notifications about incoming frosts. To make the system accessible to home gardeners, the design was required to cost under $200 to construct and be as inexpensive as possible in operating costs, measure temperature to within half a degree centigrade, be capable of operating at temperatures down to -20ºC, support ethernet connections for gardens far from the house, and must allow the gardener to configure a temperature threshold below which they will always be notified, whether or not the dew point indicates an incoming frost.
An ESP32 microcontroller, coded in C++ in the Arduino environment, was used for the final endpoint design, along with an ethernet shield and the SHT31 temperature and humidity sensor. Google Cloud services were used for the cloud data pipeline, and Google Firebase was used for a database and for communication with the iOS app. The iOS app was developed in Swift using the SwiftUI framework, with significant support from Firebase libraries for communication with the cloud.
All design goals were met by the final design except for the low yearly operating cost. This was due to the unexpected requirement of having an Apple Developer account, which costs $99 per year, in order to send push notifications to iOS apps. Due to this unexpectedly high cost, several alternative notification solutions, including an Android app and a secondary physical endpoint with alarm functionality, are proposed at the end of this report, as well as suggestions for potential commercialization.
James, Andrew, "IoT Garden Frost Alarm" (2021). Honors Theses. 2443.