Purpose:

• Playing, Filtering and gaining Soundfiles at free programmable times
• Multichannel measurement of Sound-Level of Environment
• Sensor inputs
• Webserver with graphical statistics of parameters
• Mailsever with automatic mail of recorded soundfiles and Alert mails
• Passive (low power) without moving parts and flashdrive for programs and sound

Hardware Solution:

• "VIA-EPIA Mainboard low power 677MHz" or "VIA-EPIA 5000 low power 500MHz"

(VGA, PS/2 mouse, keyboard, Ethernet 10/100Mb, 256MB RAM, 2xSerial in)

• USB-Key as Flash-Harddrive 256MB for booting and basic pd. Optional
• Fanless Power supply with 12V (35W) with external 220V Adaptor
• 1 RME9636 Hammerfall + 2xRME AEB48i (Analog ins) + 1x AEB48o http://www.rme-audio.de/
• up to 4 Microphons for Soundlevel measurements in open Space. with preamps http://www.noisemeters.com/pdf/mk429.pdf
• 19'' Aluminium Case with additional Heatsinkconnection to the chassis and XLR In/outs to Soundcard and Sensor In/outs.
• VGA Out for monitoring activity
• Sensor Inputs over Paralell Port (switches) and AD

Software Solution:

• Linux (Debian) system booting from Flashcard.
• PD pure data (see http://pd.iem.at)
• Exim Mailer-System
• MRTG Multigrapher doing Webgraphics and Statistics
• PD Programm with Adaptive Measurement and freely programmable inputs

Description:

The computer boots from an Flashdrive and could be shut down hard (power loss) without filesystem crash.

The software is freely programmable realtime PD and plays a Soundfile at a specific Soundlevel. The Soundlevel can be derived from Measurements made by inputs.

Optional, we offer also an adaptive Soundlevel Measurement. It can measure Soundlevel with cancelation of Sound from the speakers to get the real Volume. Note that the Volume must not be louder than 20dB the environment sound for good performance.

The problem is that if a range of 20~dBA until 100dBA has to be measured, the microphons has to have a good resolution. Therefore 20-Bit AD-Converters are used. The Adaptive Process has to be active since Soundspeed differs by temperature and so also times of refelections which has to be canceled. The Microphones has to be at least 5 meters away from the Speakers to cancel the latency of Audio Input on the Computer.

On use with soundinstalltions the idea is that the Microphone (or two) with the lowest Soundlevel has to be used for automatic gain control, since there must be a control over being to loud in the night or on weekends. Also time is tracked so that adaptation of the gain should be done in an frame, which is expected, otherwise a warning is send and the lower volume is taken in case any microphone input gets very noisy because of an technical defect.

The system can record an soundfile from the microphone inputs. All This data can be mailed to one or more addresses and or published on a website with authentification.

Also Bandpass filters can be calculated in the computer so that up to 8 Outputs can be used for individual filtered Outs.

If additional Sensor (Analog ones) are needed they have to be connected over additional audio inputs of the computer.

Installation and Test:

• 2 year guarantee of hardware and software
• Duplicate back up unit (mounted at place)
• Complete package of software documentation

  This includes the configuration of the debian-linuxsystem and the list of used software with version numbers. Also the used PD-patch is described with a function diagram and usage.

• Documentation for all hardware components

  List of all used components included the one which were build for this computer. and all manuals on electronic form or paper.

• Package of restoration documentation sufficient to reconstruct the work in the far future including:
  • sound system impulse response
  • sound file of output recorded at the speakers.
  • sound file of output recorded with the current-sensors at the amplifier
• Features of Installation:
  • Webserver/mailserver functions with output options to:

    LAN, ISDN (optional with modem), Cell phone (over Infrared connection or serial line, optional) ISDN and LAN can be configured with linux software packages.

  • Mics mounted either in weather protected enclosures or are Outdoor Microphones (depends on the demand of the building)
  • Preamps for Microphones
  • PC board with circuits for 10 speaker monitors as follows:

    LED (or equivalent Visual on the VGA-Screen) for each speaker which is turned on when the average current being drawn by its speaker goes above or below an adjustable range. Email alert message is also when current goes out of range.

  • Automatic time of day correction over internet every X minutes (settable)
  • Keep adaptive Soundlevel Measurement which can measure Soundlevel with cancellation of Sound from the speakers to get the real Volume
  • LAN (Ethernet) and Internet interfaces to PD over X11, (XFree86) the PD can be controlled from remote computers, which have X11 (like other Linux-Systems, Mac OS-X with X11 installed, Windows with X11-Terminals, ...)
  • A fanless computer with mainboard, fanless power supply.
  • Playing, Filtering and gaining Soundfiles at free programmable times