Story of an International Master Student and the HarvestMate Smart Planter

Let's follow the story of Karli, an international master's student from the Institute of Technology at the University of Tartu, Estonia. Karli took our Internet of Things course in the spring of 2023 because of their interest in machine to machine communication.

Karli really enjoyed the videos as they were not only material to review the topics but also used as tutorials for the hands-on lab activities. The videos were usually step-by-step guidelines of how to install and work with the hardware and the framework in practical ways.

After a few weeks, Karli had learned about the microcontroller ESP8266, WIFI networking, and MQTT protocol, and they realized they could implement a simple home automation system to control the light in their student apartment. Before, to turn on the lights, they needed to cross the living room in the dark, as the light switch was placed on the opposite wall from the entrance. Now, using a microcontroller with a relay switch connected to the WIFI router and simply Publish/subscribe MQTT protocol, they could turn their lights on and off using their smartphone. Karli was able to apply the skills they acquired in class to solve a personal problem in just a few weeks of the course.

From a survey with the students from Karli's semester, we have learned that 30% of the students used the IoT kit and IoTempower framework in their own personal projects that semester. Also, 70% of students claimed they will certainly use them in their future projects. One of the students commented: "I will definitely use it since I have now learned how to use it. To be honest, I don't really even know how to prototype projects without it."

Karli kept improving their home automation solution as the class progressed. This was made possible because of the portability and affordability of the kit and software. They could negotiate with their group mates to take the kit home, prototype with it, order the parts online cheaply, and finally deploy it as a final solution.

In week 10, it was time to come up with a challenge for the final project which the topic was "Sustainable Living." Based on the story driven modeling method, students had to come up with a scenario that would best describe a real-world challenge related to the topic and possible ways to solve it. The stories created served as tools for the groups to pitch their project ideas to the rest of the class and to come up with a detailed plan of their project's needs.

Karli's group story was about a student who had moved to Estonia and wanted to grow their own salads at home. They liked taking care of plants but were looking for a planter box that was smart. They needed a planter that would help them with watering and could also measure the light coming from the window of their kitchen and let them know if it was sufficient for their plants. If not, it would turn on the artificial lights when needed. They also wanted to collect data from soil and air and get notified with useful information about the plants.

Karli's group decided to get a planter box and equip it with sensors and services using IoTempower. That's how HarvestMate was born.


HarvestMate is equipped with sensors that can measure: The amount of natural light (APDS 9660 sensor); the water level in its water tank (Water Level Sensor); water's PH level (E-201-C-9 PH Electrode); soil moisture (Capacitive Moisture Sensor); air temperature and humidity (DHT22); and plant growth (VL53L0X LIDAR). HarvestMate uses the APDS 9660 to measure light intensity and light color frequencies and calculates how much artificial light is needed to compliment the plant's daily needs. Each day it turns on the LED growing lights accordingly. HarvestMate relies on the IoTempower framework for managing and deploying the sensors, and its gateway (Raspberry Pi 4) to run the services, notifications, local database logging, and dashboards with the Node-RED integrator for data visualization.