Measurement data from the airplane seat
Mini data loggers are primarily known for their use in machine, plant or transportation monitoring. However, data loggers can also be used with great benefit in other applications, such as in the development of new generations of aircraft seat components.
On the one hand, aircraft seats have to be very comfortable for people, easy to clean, of high quality and mechanically stable. But there is another important point: they also have to be very light, because every kilogram of extra weight means higher operating costs due to greater kerosene consumption and therefore higher CO2 emissions. All seat manufacturers in the aircraft industry are therefore very interested in optimizing the ergonomic aspects as well as further reducing the weight of the seats.
Large weight savings achievable
The Swiss company Lantal Textiles AG has been active in this sector for a long time. Lantal is a leader in the design, manufacture and marketing of textiles and services for international air, bus and rail transportation. The company developed its so-called "Pneumatic Comfort System" a few years ago. Its principle: air-filled cushions replace the conventional foam padding. This ensures increased adaptive comfort and reduced seat weight: around 1.5 to 3 kg of conventional polyurethane upholstery can be saved per Business Class seat and around 3 to 5 kg per First Class seat, with an extended range of functions.
The air chambers distribute the pressure optimally, and passengers can also adjust the degree of firmness to suit their personal preference. The air-filled cushion automatically adapts to the desired conditions in both the sitting and reclining positions - not least as a marketing argument for the airlines. Of course, this requires a sophisticated pressure control system, which also uses appropriate pumps and valves to maintain these "comfort conditions" for the passenger despite the changing cabin pressure. The pneumatic comfort system should be completely maintenance-free, meaning that the cushions should continue to work in the same way throughout their entire service life. Aircraft seats of this type are now used by a large number of international airlines, mainly in first and business class cabins.
Mini data loggers examine pneumatic control technology
The Swiss company uses the MSR145WD wireless data loggers for the further development and long-term testing of the associated pneumatic control technology. These thumb-sized mini data loggers can detect and record the parameters temperature, humidity, pressure, light intensity and acceleration/position with internal sensors at freely adjustable sampling intervals. An OLED color display serves as a display surface for parameter curves. These loggers are powered by high-capacity rechargeable batteries and have space for recording around 1 million memory values, which can be read out via USB or wirelessly via the Bluetooth Low Energy radio standard. Lantal uses the latter transmission option to check the pressure conditions in the pneumatic cushions on the test bench with the small data loggers. The company uses a good dozen of these loggers in its development laboratories.
Precisely recording pressure values
Incidentally, the internal cabin pressure of the aircraft must also be taken into account in the corresponding tests, as the air pressure in the cushions must be readjusted according to the changing ambient air pressure during take-off, landing and cruising. In the further development of the entire pneumatic system, the electronics and the associated control technology, it is particularly important that the pressure values in the cushions can be recorded together with the temperature with a high resolution using the internal sensors in the range from 10 to 2000 mbar with a measuring accuracy of ±2 mbar.
The average cabin internal pressure during a transatlantic flight is around 900 mbar - it is greatly reduced during the cruise flight at high altitudes, down to around 780 mbar - the pressure differences are therefore over 230 mbar, as the normal pressure on the earth's surface is 1013 mbar on average. The internal pressure in the seat cushions must be readjusted according to these pressure differences, which is tested with the loggers on the test stand. In addition, the relative humidity from 0 to 100 % and the 3-axis acceleration in the range of ±15 g are further parameters that are of interest for tests of this type. Crash tests with MSR loggers are also carried out in this context; all pressure values and the other physical parameters that can be stored with the loggers are recorded at very high sampling rates. Thanks to their mechanical robustness, the small loggers can withstand even these "tough" test series without mechanical or electrical damage and can also be used under very unfavorable environmental conditions, for example in the transport and logistics industry, automotive development and in all different areas of application in mechanical and plant engineering, as they are specified for the temperature range from -20 to +65 °C.
Data via Bluetooth and mobile network in the cloud
In the Lantal tests, the parameters are read out either wirelessly via Bluetooth Low Energy (BLE) or - depending on the test setup - wired via USB. In general, BLE short-range wireless technology is an advantage for applications in which measurement data needs to be monitored from hard-to-reach locations, such as from rotating machine elements in other industrial sectors. The BLE wireless standard enables the user to transmit and record data within a 20-m radius, regardless of location. In order to be even more independent in terms of location and even to be able to read out the measured values worldwide, a dedicated cloud application has been developed: The measured values sent from the data logger via Bluetooth to a nearby mobile radio interface are sent from this mobile radio gateway to the MSR SmartCloud, where they can be retrieved from anywhere in the world with password protection.
Using the "MSR DataLogger" smartphone app, the data recordings can be started, stopped, read out and sent to the MSR SmartCloud at any time. An alarm function is also available in this cloud system.
With this application in aviation technology, the mini data loggers show that they can be used in a wide range of measurement applications that go beyond machine and transport monitoring or logistics - laboratory and test bench measurement technology are also areas of application. And similar loggers are already in use on space flights to record mechanical loads.