Hackster Global Design Challenge Solution Spotlight: Precious Water

In Phaphazela, a small village in the Limpopo province of South Africa, surface water is seasonal and unreliable due to the region’s semi-arid climate. Residents occasionally have to resort to unsafe groundwater from makeshift wells. Climate change has affected rainfall patterns, adding pressure to already stressed water sources.

The government promises bulk water infrastructure, indoor water reticulation, and outdoor standpipes, but only fulfills part of the promise. Private parties have stepped in to fill the water supply gap, and water tanker operations have become a lucrative business.

While some residents are able to purchase water from the private water tankers, most of the population lack access to reliable water supply other than that provided by the government.

Once a week, every Thursday, water tankers from the local municipality roll into Phaphazela and pump clean, potable water into the communal supply tanks. Every family in the village has a domestic storage tank, and they connect hose pipes to the communal supply taps to store water for household use. There is no set time for these water trucks’ arrival, and the residents have to leave the hose pipes connected well in advance. However, there is usually no one awake to monitor and stop the water flow when the tanks are full, resulting in the wastage of an already scarce resource.

Hackster’s Restraint to Reinvention challenge, in partnership with Nordic Semiconductor, champions appropriate technology – simple, sustainable solutions to social issues in underserved regions.

Elijah Maluleke is a resident of Phaphazela village and an award-winning member of the Hackster community who is passionate about building tech for social impact.

Maluleke's submission is a “smart, solar-powered water tank level and tap monitor” device that will help address the multifaceted water supply issue in Phaphazela and its neighboring regions. The project has two important water-saving features:

• It monitors storage tank water levels and stops the inlet valve from the communal supply to the domestic storage tank when it is full.
• It senses when a tap has been left open and automatically closes the outlet valve.

The system is built on Nordic Semiconductor's nRF54L15 development kit and uses multiple sensors for redundancy and accurate measurement. It integrates a non-contact (ultrasonic) liquid level sensor and an infrared light sensor to monitor the domestic water tank level. A water flow sensor detects water flowing from the main supply line into the tank and signals the system to either open or close the 12V inlet solenoid water valve based on the current level of the water tank.

The smart tap control feature is supported by a PIR motion sensor and an ultrasonic distance unit. This combination is needed to prevent the system from detecting passers-by, animals, and other false-positives.

Maluleke is working on a smartphone app to collect water level and battery voltage readings from the system via Bluetooth Low Energy. He also plans to integrate an OLED display in a future version of the project to make it accessible for those who don’t have a smartphone. An active buzzer is included in the system to alert the users when the water level in the tank is running low. Maluleke says this will cater for the elderly in the community who can’t read due to visual impairment or illiteracy.

Maluleke's solution is simple, scrappy, and solves a major problem in his community. More importantly, it is energy-efficient and sustainable since it leverages the low-power nRF54L5 development kit and other energy-efficient components. The system is powered by a 12V rechargeable battery charged by a solar panel.

However, local adoption will not be without its challenges, as Maluleke admits. It is really hard to get people to change their behavior, even with an innovation as crucial as this. He plans to conduct a door-to-door visitation to educate members of the community on the benefits of his invention.

Appropriate technology often demands a balancing act between functionality and cost-effectiveness, but Maluleke doesn’t think price will be a major obstacle to the widespread adoption of the water level and tap monitor kit. Water is a fundamental resource that no one can do without, he says, and the kit is cheaper than purchasing water from the private tankers. Still, he mentions that “alternative plans will be put in place to ease the purchase” of the device.

If the device sees widespread installation, people in Phaphazela will be able to save thousands of litres of water, which will improve the availability of local food, influence public health, and ease the financial burden of purchasing water from water tankers.

A lack of maintenance is the cause of the early demise of most appropriate technology, but in this case, it is helped by the innovator being a resident of the local community. Maluleke says he will conduct monthly checkups on the installed devices to ensure that they continue to operate smoothly. He plans to include Memfault, a cloud-based debugging platform, in future updates for bug detection and remote diagnostics.

According to UNESCO, between two and three billion people worldwide experience worse shortages. The global water crisis is a worldwide problem, but it can be solved one village at a time by people like Maluleke who choose to reinvent restraints into possibilities.

You can read about Maluleke's project in detail here.