For ARP elektro group s.r.o. we provided design and production of GreenBox control unit hardware including system firmware based on Linux/Yocto. The device is used for intelligent control of photovoltaics, for example heating water in a boiler or charging an electric car via a wallbox. The project included PCB design in Altium Designer, EGModule integration, communication via Microsoft Azure IoT, prototyping, pre-series production of 50 units, certification and preparation of the first batch of 300 units for the Czech market. This project shows what professional custom electronics development can look like from technical specification to mass production. It is a demonstration of what we do every day: creating new functional, safe and reliable devices.
How does GreenBox work?
One of the leading Czech suppliers of PV plants is ARP elektro group s.r.o. In January 2025, the company launched an innovative PV control system – GreenBox.
The GreenBox can intelligently control water heating in the boiler or charging of electric cars via the wallbox. Communication is via Microsoft Azure IoT and control is fully integrated into the mobile app. It represents an evolution in photovoltaic control – not a revolutionary technology, but a sophisticated and precise solution tailored to the needs of customers.
We provided hardware and firmware development
Arpeg approached us with a request to design and manufacture the hardware for this unit, including the system firmware, i.e. a customized operating system (Linux/Yocto) with configured peripherals, update solutions, connection setup functions and other details.
Technical Solution – EGModule and Functional Label with LEDs
The foundation of the unit is our Linux SOM module EGModule built on the ARM/Allwinner A64 platform. It runs at 1.1 GHz with 1 GB of RAM and full embedded Linux support (Yocto), along with 8 GB of flash memory. We developed the module a few years ago for our own use as a Replacing Raspberry Pi Compute Module 3. We have integrated Ethernet, RS-485 (Modbus-RTU) for industrial communication and USB ports for configuration and firmware updates. In addition, during the development process, we added a customer-requested and Wi-Fi connectivity.
The device is in a standardized box, designed for installation in a switchboard. Industrial designers did not get a say in this case – but the label is interesting in a different way: LEDs are integrated directly in the labelthat indicate the status of the unit, network connection and power supply. This has saved space and costs for a separate PCB with LEDs or light pipes inside the unit. We used common membrane keypad technologies.
The software application part was handled by another vendor, with whom we collaborated to connect our firmware with the Docker platform and Microsoft Azure IoT.
From prototype to series production
The development involved a complete process from schematic and circuit board design in Altium Designer, through prototyping to pre-series production of 50 units.
During this process, we worked closely with the software vendor to debug our system with the Docker-based application under development and Microsoft Azure IoT.
Now we have completed the final testing and certification without losing a flower, and we are starting the production of the first full batch of 300 GreenBoxes for the Czech market.
The development of electronic devices is not about marketing promises, but about daily honest work and precise engineering. GreenBox is just that – a thoughtful solution designed to meet the exact needs of our customers. And that’s where its real value lies.
Are you dealing with a custom controller, IoT device or need a different type of custom electronics?
We can help you with hardware design, system firmware, prototype, pre-series production and certification preparation. Send us a technical specification or a description of the problem and together we will check what development process makes sense.
