ZigBee prototype project

Introduction – Mountain Cottage automated

As UniPi develops further and further, new possibilities arises before us. We work on new projects as well as our customers. Until now, UniPi has always been wired. But with all the hard work put into the development wireless communication for our control unit is becoming true in the near future. Actually, we already test the prototype project.

Member of our team has decided to improve comfort of his mountain cottage in the Austrian Alps using both wired and wireless communication. The project focuses on heating management, temperature and humidity measuring and monitoring of unwanted presence.

Project goals

Before the project’s creation, there is a few conditions to be considered and determined goals.

  • Already buildthe already mentioned mountain cottage has been built years ago. The goal is to make minimal adjustments of the building.
  • Old boilerwater in central heating is heated up with a 30 years old oil boiler. Let’s use what is already included.
  • Remote controlowner does not live in Austria and remote control may come in handy as well as continuous monitoring.
  • Equitherm regulationthe heating system about to be build needs to be smart and needs to adapt to constantly changing conditions.
  • Unwanted presence detectionwhenever the cottage becomes a target of burglars it is good to know and contact the local police.

About ZigBee – Which frequency are you on?

With the necessity of minimal building adjustments it is clear that wired technology is not always optimal. For this purpose, wireless Zigbee sensors were included. But what is the ZigBee anyway?

ZigBee is the open wireless standard for Internet of Things. This standard enables mutual communication between many smart devices all supporting the same standard. The advantage of ZigBee is its openness compared to Z-Wave which uses proprietary technology. More about ZigBee and The ZigBee alliance you can read here.


One of the two NYCE’s wireless Motion Sensors used in the project.

Connection schema – How did we build it?

To get more idea about the system connection lets have a look at the complete connection schema below and following system description.


The connections schema of all the devices and measurement sensors

As in all projects, UniPi board serves as the master control unit. This time it is equipped with Raspberry Pi 2 model B. To the Pi computer there is a ZigBee chip which provides access to the motion sensors (which sends the temperature and humidity readings as well).


ZigBee ETRX357 module for the control of wireless sensors

This is the very first use of wireless IoT technology together with our board. It is the prototype usage but the communication is without any issues and the compatibility is non-problematic. And so UniPi is very close to the full support of the wireless smart home devices.

To the control unit’s 1wire port is connected 1wire 8 port hub. The HUB then connects Several 1wire thermometers with the board.


Distribution board with UniPi. The ZigBee chip is marked with the red rectangle.

The picture above shows detail of the distribution board of the house. There are four relays for the system functionality and the industrial power supply for the UniPi board. The installation enables manual control as well.

Relays are marked with numbers. These numbers correspond with the numbers used in the system schema shown before. Relay 1 switches the stronger relay on the left which controls the water heater. Relay 2 switches the circulation pump and the Relay 3 switches the old oil boiler for central heating. Relay 4 switches the industrial power supply powering the UniPi board.

Software – Whats behind this?

Whole system runs Mervis, our official PLC software which is in accordance with standard IEC 61131-3. Mervis communicates via proxy server and user can then use SCADA (Supervisory control and data acquisition) system. Temperatures, humidity and movements are periodically logged into cloud database and can be later sorted and viewed accordingly to chosen criteria.

For the programming the ST language was used. This language is one of the supported methods how to program PLC software meeting the IEC 61131-3 standard.


Mervis SCADA web interface with custom stat readings seen from the smartphone.

Mervis is extendable system supporting many plug-ins. Though the project does not include this in the programming it is easily possible to connect Mervis to the weather forecast. This may come in handy for example when you have a watering system in the garden. The possibilities are many and we sure came up with another great project.

Photo documentation


The boiler room with the distribution board.

One thought on “ZigBee prototype project

  1. mervcolton / Reply 2016/03/20 at 6:22 pm

    Looks very interesting, and similar to a project I’m working on in Ireland. I’ve hardwired some circuits using the Unipi – all for lighting and utilizing momentary switches through the house.

    I now want to do some more, and the Zigbee element interests me. Pls keep doing updates as the project progresses!


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