Seventy-one percent of the Earth is water. Of that, only three percent is fresh drinking water. We have solutions like recycled water and riskier ones like desalination to try and keep up with increasing demand, but more needs to be done in the face of depleting water reserves and overpopulation. Contamination and pollution of water is a very important issue in today's society. Protecting the water reserves we have is a step towards being smart with our freshwater.
My project, Clear Dome, aims to be a completely self sufficient, maintenance free IoT water quality monitor. Firstly, its power delivery system is completely sustainable. It features a solar cell with a TP4056 charging board and an 18650 3400mAh battery. This alone allows the device to be implemented without a issue of charging the battery. Secondly, the mircocontroller in question, the Particle Boron, allows for 4G/LTE connectivity, meaning transmission of data can be handled off-site, anywhere in the world with coverage. In addition, the Particle Mesh series of controllers allows for connectivity "mesh" between Particle devices, allowing one body of water to be monitored by a single Particle Boron and multiple Particle Xenons in other nearby points of interests. The Particle Xenon shares the network provided by the Boron and acts as a slave device to the Boron. These two features alone already allow the device to operate off-site without any human interference necessary.
Clear Dome will have multiple features important to monitoring water quality in a body of water. There are three categories of water quality targeted and monitored by this device: Acidity/General Quality, Turbidity, and Contaminants. Firstly, the devices uses a conductivity sensor and a temperature sensor. Using basic analog readings of the conductivity we can determine that a higher conductivity will result in a lower quality of water as this means a higher content of sodium, chloride, and magnesium. In addition, we need to use a temperature sensor to calibrate the conductivity sensor as the resistivity of water changes with its thermal signature. Another system to monitor these qualities uses a dual channel relay, solenoid valves, and a TCS34725 color sensor. The device first allows water from a point of interest into a reservoir within the device by switching a relay and toggling a solenoid valve. Then, another solenoid valve can deposit a chemical to test for contaminants. A color sensor would then see if the solution changes color in the presence of a contaminant or metal. An example would be presenting sodium tetraphenylboron in a potassium rich water solution. This would then form white precipitate which the color sensor would be able to pick up. In addition, a photodiode voltage divider would be used to observe turbidity of the water when positioned across from the color sensor which has a LED on-board.
These sensors together allow for a system that gathers important data on water quality while being completely self sufficient to last over a year in the field. Clear Dome features an easy cost effective device that enables increased awareness of water conditions. A PCB can be easily produced and a sealed, watertight body can be constructed to house the system. In addition, the marginal cost of a system decreases with each device as Clear Dome can make use of the Particle Mesh network, opting for a cheaper Particle Xenon(15$) geographically nearby a Particle Boron(50$) at a different point of interest. These devices can work together to monitor a body of water, performing tests and reporting its data off site. A mesh system like this would be easy to implement and would be robust to any changes or failures.
The impact of Clear Dome cannot be understated as it effectively allows people to know if their water is healthy to use and drink. Clear Dome can affect many people in any country. Even in America, there is a use for the Clear Dome in the EPA's superfund projects where they can use Clear Dome to quickly determine a source of runoff, monitor a point source, and continuously be updated on its status remotely. This will help clean up any hazardous conditions and identify unhealthy areas, protecting the clean water across the globe in any situation.