Smart infinity pool automatization with Mervis and the Unipi 1.1

References

A customer from the south of France uses Unipi 1.1 PLC and Mervis software for the automation of an infinity pool.

Unipi 1.1 is an extension for the Raspberry Pi computer that allows it to function as a programmable logic controller (PLC). Thanks to its affordability and simple design, Unipi 1.1 is a great solution for smaller projects, prototyping, monitoring, control, and regulation, or smart home installations. The last-mentioned application was also used by our customer from France, for his infinity pool.
Infinity pools (or infinity/zero edge pools) are built so that water from the pool flows over one or more edges, giving the illusion of a never-ending surface of the water. The water is then drained into a balance tank, from where it is pumped by filter pump back to the infinity pool, which creates a closed unit. Our customer decided to automate this entire management.

Problem

The original control of the infinity pool used a mechanical timer to check the filter pump, which had to be set manually each time the temperature changed. Because this procedure was not economical nor time-efficient, our customer decided to automate this task using Unipi 1.1 control unit.

Solution

Thanks to the possibilities offered by the controller, the customer has extended the project of automating the control of the filter pump with other applications.

Unipi 1.1. currently controls:

filter pressure: as soon as it exceeds the set limit value, the filter should be cleaned. There is no need to check it manually anymore so it is a time-saving solution.
pH and ORP (Oxidation Reduction Potential) of water: thanks to these values, the user knows whether the water is not only clean but also sufficiently sanitized (it has a reduced number of bacteria and microorganisms, thus preventing disease transmission or contamination, etc.). ORP of water also helps monitor/limit the rate of pool electrolysis.
air temperature: if the temperature drops below 0 °C, the controller starts regularly the pump, which circulates water in the pool. As a result, it does not freeze in the pipes and thus prevents freeze damage.
water flow detectors: act as a safety measure to allow the pumps to be switched off if no water flow is detected (e.g. unexpectedly closed valve, etc.).
the water level in the balance tank: the moment the water level drops to the specified value, a solenoid valve opens and fills in the tank with water. In addition, the customer connected a warning system in case the water would drop to an even lower, critical level. Doing so could otherwise damage the pump.
energy and water consumption: is recorded by simple pulse meters connected to the digital inputs of the controller. Using these values, the customer can calculate the current flow and monitor daily and weekly consumption.

Software solution

The customer used the Mervis system as a software solution, an officially supported complete platform for Unipi products. The Mervis HMI (Human Machine Interface) editor was also used for creating a graphical web interface. The customer has created an application for a mobile phone that monitors and controls the entire operation of the infinity pool.
All data from the project are sent to the cloud database Mervis DB, which is used to store the history of variables from the PLC to secure storage in the Unipi data center. Thanks to this solution, alerts (warnings about the limit values of certain variables) are sent by the system to the customer automatically via e-mail.