Development of an Open-Source Real-Time Water Quality Monitoring Device : a Modular Approach
Sword, Philip (2025)
Julkaisun pysyvä osoite on
https://urn.fi/URN:NBN:fi:amk-2025052817701
https://urn.fi/URN:NBN:fi:amk-2025052817701
Tiivistelmä
Lakes worldwide face persistent eutrophication problems from excess nutrients (especially nitrates and phosphates). This nutrient overload causes algae and plant overgrowth, creating physical and chemical changes that render waters unsuitable for industrial and recreational use.
The high cost of direct nutrient measurement necessitates monitoring proxy parameters, where trends prove more valuable than absolute values. Two prominent indicators are the total dissolved solids and pH. When the total dissolved solids (TDS) levels change in conjunction with pH, they become strong indicators of the consequences of eutrophication.
The thesis discussion outlines a functional live-data, Internet of Things (IoT) minimum viable product (MVP). For processing and telemetry, the MVP uses an ESP32 microcontroller. The MVP is suitable for controlled tests in an indoor environment. Temperature, TDS, and pH are the three properties the prototype measures. Total dissolved solids and pH can change due to ongoing chemical and physical processes, while temperature is measured primarily to adjust the pH and TDS values.
The project was executed in three interactive phases: hardware and firmware development, performance testing, and sensor validation. The three tests include real-time measurement capability, datalogging features, and data transmission to an IoT platform. The device successfully demonstrated its data collection and transmission capabilities. This functionality is sufficient to prove the expected operation, defined by the thesis scope.
Validation tests highlighted the need for improvement in sensor precision and power efficiency. Specifically, observations support the pH sensor being faulty. This discovery was due to unexpected and significant deviations between tests and during calibration. The system is otherwise functional. Dependability will improve pending sensor replacement, further calibration refinements, and analog isolator insertion. Finally, the appendices contain sufficient material to support reconstruction of the working prototype.
The high cost of direct nutrient measurement necessitates monitoring proxy parameters, where trends prove more valuable than absolute values. Two prominent indicators are the total dissolved solids and pH. When the total dissolved solids (TDS) levels change in conjunction with pH, they become strong indicators of the consequences of eutrophication.
The thesis discussion outlines a functional live-data, Internet of Things (IoT) minimum viable product (MVP). For processing and telemetry, the MVP uses an ESP32 microcontroller. The MVP is suitable for controlled tests in an indoor environment. Temperature, TDS, and pH are the three properties the prototype measures. Total dissolved solids and pH can change due to ongoing chemical and physical processes, while temperature is measured primarily to adjust the pH and TDS values.
The project was executed in three interactive phases: hardware and firmware development, performance testing, and sensor validation. The three tests include real-time measurement capability, datalogging features, and data transmission to an IoT platform. The device successfully demonstrated its data collection and transmission capabilities. This functionality is sufficient to prove the expected operation, defined by the thesis scope.
Validation tests highlighted the need for improvement in sensor precision and power efficiency. Specifically, observations support the pH sensor being faulty. This discovery was due to unexpected and significant deviations between tests and during calibration. The system is otherwise functional. Dependability will improve pending sensor replacement, further calibration refinements, and analog isolator insertion. Finally, the appendices contain sufficient material to support reconstruction of the working prototype.