The WaterElf is an ESP32-based control, monitoring and communications device for aquaponics. It combines several features characteristic of different greenhouse control systems and water quality monitors used in aquaculture and hydroponics. The latest version of the WaterElf features wireless sensors to measure pH, light intensity (LUX), water temperature, air temperature and humidity as well as 3 ultrasonic sensors that enable the monitoring of water levels in 3 growbeds from a single device. A programme controlling the opening and closing of valves, thereby regulating water levels, runs locally in the Elf. The timing of this is controlled by the water level (high water levels sending a signal to stop the flow) – if for any reason this signal does not come, filling of tanks will automatically stop after 15 minutes to prevent overflow.

Figure 1. The 1st (top) and 6th (bottom) generation of the WaterElf

Data collected by the WaterElf is uploaded to the cloud for storage and analytics, from where it can be accessed from any smart device. A dashboard (see Figure 2 below) displays changes in different parameters over time. It is also possible to get a real time image of the aquaponic unit thanks to the option to connect a camera to our device. The WaterElf moreover has a customizable alert system – including text, email and twitter alerts – which makes looking after plants and fish a much easier and less stressful task.

Figure 2. Dashboard showing different parameters of the aquaponic environment measured by the WaterElf

Both the software and the hardware of the WaterElf were designed to be modular and expandable, which, together with the open source nature of our product, makes it possible to easily integrate it with other systems or further customised developments. For example, it could control LED lights, heaters, or fish feeders.