A customer from the Czech Republic uses the Unipi 1.1 PLC to control heating in a family house.
The Unipi 1.1 expansion board represents a simple way to transform the Raspberry Pi computer into a programmable logic controller (PLC). Thanks to its simple construction and favourable price, the Unipi 1.1 is a perfect solution for small projects, prototyping, education or smart home systems.
The latter includes a project made by a customer from the Czech Republic, who utilized the Unipi 1.1 for control of heating and hot water distribution in his household. The controller is connected to a cartridge heater, maintaining a preset temperature of water in an accumulation tank. By regulating a three-way valve, the Unipi 1.1 also controls the flow of hot and cold water into a floor heating system, with its temperature set by an equitherm curve. To save energy, the circulation pump is used only when the house is occupied. The pump is currently switched according to a time plan, with detection of mobile phones connected to the house’s Wi-Fi network planned for the future.
Simplified project scheme
From the software point of view, the customer controls Unipi 1.1 via custom software communicating with the PLC through EVOK - a set of open-source web service APIs. The microSD card, used as Unipi 1.1’s memory storage, stores only a bootloader for booting from an external SCSI drive. This solution prevents issues with the microSD card’s reliability and significantly increases its lifespan.
As to future plans, the customer plans to expand the project by control of pumps for solar collectors, central control of shades and louvres, and detection of low energy tariffs.