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	Sensorlab
	The STEIM SensorLab is a small, general purpose, analog to Midi interface for the prototyping of musical instruments and interactive control systems. Whether the computer is a central element in an artists work or simply a tool bridging a technological gap, the need for real world input and output is essential. The SensorLab connects the real world of physical phenomena and gestures via Midi to personal computers and to Midi musical and studio devices.   The SensorLab is basically an analog to Midi converter. It is a small custom microcomputer which can convert incoming analog electrical information into a standard digital code [MIDI] which can then be interpreted by a personal computer or directly connected to standard Midi devices such as mixers, synthesizers, samplers, special effects devices and lighting controllers. Personal computers such as the Macintosh and Atari are practically limited by the difficulty of interfacing them to the outside world. The need to make this interfacing easy led us to the SensorLab design. The SensorLab interfaces analog information by converting it into a form [MIDI] which all microcomputers and most electronic instruments can handle.   A variety of projects at STEIM in recent years have led to the emergence of the SensorLab design. These included entirely novel "instruments" such as The Hands, the Midi Conductor and The Web of Michel Waisvisz, an ultrasound violin bow, a Midi controlled motorized camera mount and several Midi conversions of conventional instruments such as a Bass Recorder, a Concertina and a Melodica. The variety of sensors needed to complete these projects [switches, potentiometers, pressure pads and ultra-sound devices] forced our design towards the accommodation of a wide range of real world signals. No doubt this should allow us to make new instruments and interfaces for some time to come. > > > > > > > > > > > > > > > > > >		Unfortunately, the Sensorlab is no longer for sale. We are working on a new solution for interfacing sensors.   The user has to deal with two different issues in the design of a new controller. The first is to choose a physical effect or sensor which detects the gesture to be interfaced to the computer. The second is to adapt that sensor to the practical and musical needs of the equipment you wish to control i.e. your computer software or MIDI instrument. In trying to follow the dynamics of a crowd of people, for example, one might opt for light sensors to detect their arrangement and movements or use a microphone and filter to measure an envelope of the noise they produced.   To add a gesture control to a Trumpet one could attach an ultra-sound transmitter to measure the change in distance to a receiver a few meters away. Either method results in changing analog voltages which the SensorLab can convert into a stream of MIDI messages. These messages may be used directly or passed to a bit of intelligent software for further interpretation. VVVVVVVVVVVVV VVVVV VV
	MIDI   A general numerical code for moving data via cable from one computer controlled device to another with certain practical limitations in speed, roughly 1000 messages per second. The finesse required of the user is both in the design and deployment of the sensors and in the fitting of the signal they produce to the range of Midi messages. Standard Midi can handle data of several sizes, the most common being so called "7-bit" messages which allow a precision of about 1%. Higher precisions are possible with longer Midi messages. The strongest constraint on the precision of messages sent is not usually the SensorLab or Midi itself but the limitations of the Midi consuming devices such as samplers and synthesizers. V V V V V V V V V   Spider programming environment   A resident interpreter allows user programming of alternate Midi maps, dynamic response shaping, level detection etc. Performance characteristics can be programmed via Spider, a user instrument configuration and Midi mapping language which runs on any Apple Macintosh, also communicatiing with the SensorLab via Midi. User programs and signal responses can be downloaded and saved in long term battery backup RAM. Additional features of the built in software include: Dynamic Midi mapping Paged "presets" or alt-mode-keys Data Filtering: only changes of a specified quantum are translated to Midi Thresholding: Midi transmitted only at specific level crossings Dynamic Scaling of analog data: the same sensor can be mapped to Midi via different maps at different measurement scales thus increasing the sensitivity of an instrument while staying within the limitations of Midi. A distance measuring sensor which operated over a one range, eg measuring a flute key closure, could be dynamically set to convert another, much smaller range of movement as "aftertouch" once the key had "closed".		Hardware Specifications   Sensorlab box: size 3,5 x 10 x 20 cm Power Supply: size 7 x 10 x 15 cm 8x16 DIODE MATRIX KEY SCANNING (128 keys) 32 ANALOG TO DIGITAL CHANNELS 8bit resolution with 0..10x SCALING , +/-6VDC input range, 4ms. nominal sample rate (application dependent) 2 x 3 ULTRASOUND distance measuring (14bit resolution) 2 x "I2C". bidirectional serial bus 32K BATTERY BACKUP RAM. ASCII DISPLAY option (DLG2416)   Midi Specifications   7 bit data can be mapped to standard Midi message: key#, velocity,controller etc... Higher precision messages are possible Spider Programming Environment (Compiler for Apple Macintosh systems) Alternate Midi Maps dynamically selectable System exclusive supported Merging of external Midi with outgoing sensor data stream > > > > > > > > > > > > > > >
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