Deutscher Fluglärmdienst e.V.

Technical Method of our low-cost Noise Measurements
Sensor and A/D conversion (A/D = analogue/digital)
The sensor has to be installed outside the house.
Attention has to be paid to protect it against wind and weather.

The sensor is connected to a micro-controller by a cable of 2 m length. This cable can be extended by a maximum of further 5 m.
operation voltage:12V
measurement range:30dB(A) .... 100dB(A)
output voltage:0V ... 2,5V

The micro-controller has to be installed inside the house.
It uses electricity (12V =, power supply contained in delivery).
From the micro-controller, a normal serial cable provides the connection to the PC.

left: sensor
center: micro-controller (length 12 cm)
top right corner: power supply
bottom right corner:serial connection to PC (can be extended up to 50 m)

Costs: 165,00 €.


PC
A cast-off old device with Internet connection, running with any Windows system (from Windows 98SE upwards) will suffice.
Attention: Our programmes will also run with Windows 95. But we advise against Windows 95, as this operating system shows considerable instabilities in building up an Internet connection.
Recommendation: Win98, WinME, WinNT, Win2000, WinXP, Win7

The PC has to be provided by the installer of the station.

From January 2004 on, the software is also available for LINUX !
Costs: old PCs can most often be found free of charge.


Software
All in all, you need two programmes:

Programme 1 for the gathering of of measured data
This programme gathers measured data and passes them at an interval of 1 hour to programme 2.

Programme 2 for the data transfer to the Internet
This programme copies the gathered data to our Internet server.

All other programmes run on the Internet server.

Costs: 0,00 €, as all programmes have been developed by 'Deutscher Fluglärmdienst e.V.' and can be used as Freeware.


FAQs (frequently asked questions)
I want to have a station, too. What preconditions have to be met ?
1.   195,00 € material costs (sensor and micro-controller with power supply)
2. The sensor has to be installed outside the house, the micro-controller inside the house. Maximum cable length is 7m. The micro-controller needs an external power supply, i.e., there has to be a socket nearby.
3. You need an old PC and a place where to put it.
Micro-controller and PC are connected by a serial connection cable (maximum length 50 m).
4. The PC needs an Internet connection, i.e., either a modem, an ISDN card, or a network.
Depending on the type of this Internet connection, a free phone socket may have to be nearby.
5. If you enter the Internet via phone, we recommend an ISDN connection.
We do so not because of the amount of data processed (it is extremely low: 21 kB per hour), but to avoid conflicting use with your private phone (only one exchange line).
If you have only one exchange line, however, the software may also be configured in a way that your data are, for instance, transmitted only once a day, e.g. in the midst of the night.

How high are current costs ?
Power for permanent operation of your PC: depending on the PC
(With unsupervised operation, the monitor is not to be switched on)
Internet fees: depending on your contract
The most expensive solutions work in the Internet-by-call mode and today cost about 0.01 € (per connection) x 24 hours x 365 days, i.e. less than 90 € a year.
The cheapest solutions are the Flat Rates: 0.00 € (if already existing)

I have the sensor XYZ. Can I connect it to you ?
Basically YES. But this means work - and time is our scarcest resource. You will have to solve the problems on your own - our help will be restricted to giving know-how support.
Variant 1: The device has a voltage output of 0 to 2.5V
Then it can just be connected to our micro-controller.
Variant 2: The device has no voltage output of 0 to 2.5V
Then the measured values have to be fed to the PC in some way or other - it is not difficult to write an adaptation programme to achieve the logical connection to our system.


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