Re: distance sensors and midi

[Jennifer Steinkamp <jennifer@artcenter.edu>]

> Date: Sat, 18 Dec 1999 06:35:02 +0100
> From: sk@zkm.de (Sukandar Kartadinata)
> Subject: Re: distance sensors and midi
>
> >>Hi, I am looking for a quiet distance sensor solution. I have I-Cube. I
> >>am looking for something that works at around 10-20 feet. (I heard
> >>I-Cube is coming out with something mid-Jan., that is too late.)
> >>Thanks,
> >>Jennifer Steinkamp  jennifer@artcenter.edu
> >>Artist
> >
> >Maby the Sensor-Lab with Ultra-sound will do ?
>
> yes, ultrasound is usually the (relatively) easiest way to measure
> distances for the specfied range
> if it needs to be reflective (i.e. the object should not wear any
> electronics), I recommend using the Polaroid transducers, although those
> are not reallly quiet I have to admit. So maybe a cluster of standard
> transmitters (each with its own buffer circuit). Be also aware that the
> angle is limited to about 20 degrees for long distances, so you might have
> to fan this cluster...
>
> the other catch is that you need something to convert the time lag into a
> voltage if you want to use the iCube. I have done this with PIC
> microcontrollers. The BASIC stamp stuff is a little easier to use and has
> macros for ultrasound and analog output (via PWM). However, if you've
> already committed yourself that far it actually makes more sense to program
> the PIC to output MIDI directly rather than taking the "analog detour".
> Saves you lots of resolution - I usually do double controllers (14bit)
> the SensorLab has indeed 6 ultrasound channels, so if time is your major
> concern I would suggest to get one, as it is far easier to program than any
> microcontroller stuff (it's around 3000 hfl, available at www.steim.nl)
>
> good luck
> Sukandar
>
> >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
> Sukandar Kartadinata
> Custom Technology for the Arts
> Hagenauerstr. 6, 10435 Berlin, +49-30-44051219
> http://members.xoom.com/Sukandar/
> <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<
>
>
> >Maby the Sensor-Lab with Ultra-sound will do ?
>
> this works.....but good luck finding an available sensor lab, they are not
> made anymore....and they are/were considerably more expensive (and more
> powerful)....
>
> try a polaroid ultrasonic sensor that is modified to output 0-5v (for the
> i-cube)  in relation to distance...there is a company (who?) making a stand
> alone ("self pinging") polaroid (for about $50) that does this....Polaroid
> pointed me to them several years ago, though I never bought one....they
> also had a scheme for several sensors (coordination of the
> pinging)......so....call polaroid...they should be able to point you to
> this company.... also....there are other people lurking on this list who
> have considerable experience with ultrasonic sensors to control
> laserdiscs,motion control....etc....the robotics community uses tons of
> ultrasonic sensors....
>
> best....aaron
>
> - --

Hi, Happy New Year! Thanks for all the messages, I tried calling and emailing Poloroid, they do not seem to know about ultrasonic sensors. A few more clues would be great.

SensorLab is still listed on the Steim site, I emailed them as well, waiting to hear.

Just to recap: I am creating an interactive art installation next month. I am looking for 12 QUIET distance sensors that work within a range of around 3 meters. I am currently using Macromedia Director on 6 Macs, an ICUBE Digitizer, and some midi interfaces. As you know,
the Icube can take sensors with a voltage range from 0-5 volts. Icube's ultrasonic sensor is too noisy. I am using standard Midi messages; Cont Ctl.

You can see examples of my installation at: jsteinkamp.com/jimmy
Six Mac Graphites for the video, Two images per computer.

I hope that is enough info.

Thanks Again,
Jennifer

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