University of Vaasa Case

A home comfort application

Home comfort is an important issue for every inhabitant. Some homes have already a temperature sensor which can be fixed. One sensor is typically not enough to characterize the microclimate of a room. For example, air flows are very difficult to detect yet they cause discomfort for many persons. Since many sensor systems are fixed, they might not be suitable for older houses or renters. To overcome this, a system with three portable sensors.

The selected sensors were RuuviTag sensors which are open source. One sensor is shown in Fig. 1.

Fig. 1. A RuuviTag sensor.

The sensor is portable so it can be placed different positions. It also has a free app.

The general schema of build system is shown in Fig. 2.

Fig. 2. Sensors are connected with Bluetooth to a raspberry which is connected to computer. Data analysis is done in Grafana platform.

Fig. 2. Sensors are connected with Bluetooth to a raspberry which is connected to computer. Data analysis is done in Grafana platform.

To test the system for air flow detection, three sensors were placed in different position inside a room as shown in Fig. 3.

Fig. 3. Air flow detection test set up.

The system was tested by opening a window. The temperature and acceleration data for two sensors indicate a reaction to this opening (Fig. 4 and 5). This shows that it might be possible to detect air flows based on sensor data inside a room. Another possible application is characterization of microclimate inside a room.

Fig. 4. Acceleration data from different sensor.
Fig. 5. Temperature data from different sensors.

Source of most images and more information: J.B. Martinkauppi & H. Haq, “Portable IoT-sensoring system for temperature and air flow evaluation”, SDEWES 2020.