Year 3 Project

20/10/2025 I connected the heater through Relay Channel 1 (connected to GPIO 25). The 12V supply positive was connected to the COM terminal of the relay, and the normally open (NO) terminal was connected to the positive terminal of the heater. The heater’s negative terminal was connected directly to the 12V ground. This setup ensures that the heater only receives power when the relay is activated. Since water and electricity are involved, I double checked all connections and ensured proper insulation. 22/10/2025 I wrote the first version of automatic temperature control code. The logic was: -If temperature drops below the lower threshold, turn heater ON -If temperature rises above the upper threshold, turn heater OFF Later, I added a cooling fan to Relay Channel 2 (GPIO 26) using the same wiring principle as the heater. While testing, I noticed rapid switching when the temperature was near the threshold. To solve this, I slightly separated the upper and lower limits to avoid consta...

12/10/2025 This week I moved on to testing the pH sensor module. The module was powered from the 5V rail, with ground connected to the common ground rail, and its analog output connected to GPIO 36, which is one of the ESP32’s ADC input pins. I learned that the ESP32 converts analog voltage (0–3.3V) into digital values using its ADC. Therefore, I needed to map the raw ADC readings into pH values after calibration. At first, the readings were unstable and fluctuating. After some research, I understood that the pH probe requires time to stabilise in water and also needs calibration. After adjusting the calibration potentiometer on the module and allowing the probe to sit in water, the readings became more consistent. 14/10/2025 I started working with the relay module. The relay board was powered using 5V and GND from the breadboard rails, and the control pins were connected to GPIO 25, 26, and 27. I wrote a simple test program to switch each relay channel ON and OFF. At first, the relay...

  5/10/2025 After finalising the SMART objectives, I started working on the practical setup of the system. Before connecting any sensors, I placed the ESP32 on the breadboard and connected its 3.3V, 5V, and GND pins to the long power rails on the breadboard. This was done so that any component can later be powered easily without repeatedly connecting wires directly to the ESP32. It also makes the wiring more organised and reduces mistakes. When I first tried uploading code using the Arduino IDE on my personal laptop, I faced issues with the ESP32 board libraries. The board was not recognised properly and some required libraries were not compiling. To check whether the problem was hardware or software related, I tested the same setup using the university lab PC. The code compiled and uploaded successfully there, which confirmed that the issue was with my laptop. For a short period, I was only able to test and upload code during lab hours. Later, after reinstalling the Arduino IDE a...

 1/10/2025 After meeting with my supervisor, I learnt the following: -The need to complete the risk assessment before starting anything with the project.  -No ethical approval is required as the project will not deal with people or animals. -The project objectives should be specific, as mine were general. -The need to complete the project plan as soon as possible.  As a start, the risk assessment was completed. Water and soldering were the major risks for the project, but under the appropriate control, they can be avoided.  2/10/2025 The next task for me is to set specific objectives for the project. The system should be able to change the water regularly, dispense food, maintain the optimal water quality, and indicate important values using IoT. To set specific objectives, I should answer the following questions: -What type of fish will the system be suitable for? -How often should the water be changed? -What percentage of the water will be changed? 100?! -How ...