Forums > MaxMSP

Elevator tracking/sensoring

July 11, 2006 | 9:01 am

Hi list,

Id like to track the motion of an elevator within a building for a
sound-art installation.
Has anybody ever done this ? What kind of device could i use for that ?
Accelerometers ? Are there wireless ones on the market ?

Id be thankful for any ideas on this….

cheers.
m


July 11, 2006 | 11:56 am

hall effect sensors ?

http://en.wikipedia.org/wiki/Hall_effect_sensor


July 11, 2006 | 12:49 pm

last autumn i tracked an elevator’s motion using an accelerometer
mounted on the top of the ceiling. it wasn’t wireless, but i had
connected a mac mini up there to control some lights using a
usb-serial adapter and a PIC. depending on your comfort level with
electronics, you could roll yourown wireless solution (rf, wifi,
bluetooth if the distance from the machine is’nt too great).

while the results were (somewhat) stable, the elevator suffered from a
fair amount of jiggle and that tended to throw things off since I was
attempting to track which floor people were on. also, the elevator’s
timing was a bit inconsistent from floor to floor. we didn’t have
much time to set it up in there so that added to the general chaos in
the space.

another idea we tossed about, though i don’t know if it would apply to
your situation (certainly didn’t to ours), was to install a camera in
the elevator, pointing at some sort of visual cue in the elevator that
displayed the floor number (a big lcd, one of those arrows with light
up floor numbers, etc) and use some image processing to identify the
floor.

the best way, if the building has it, and you’re allowed, is to tap
into the building’s security system and use that to monitor what floor
the elevator is on.

good luck, and i’d love to hear what solution you come up with!

~s


July 11, 2006 | 1:18 pm

How about sonar? That’s what all the robotics people use these days (polaroid kits)

I’ve done measurements using sonar in the past, and it was precise enough, at least down to 10 cm or something (this is from memory, so I could be wrong though)

Most elevator shafts have enough space in the bottom to mount a sensor system like this.

I could also imagine a system of a wire wound on a spool with an encoder sensing how many turns of the spool in either direction.


July 12, 2006 | 2:10 am

I did some pretty coarse elevator tracking by sticking a contact mic on the motor. That might be another place to look. Be careful, in the US, the elevator inspectors don’t like it when you get too close to the equipment.

mz


July 12, 2006 | 2:46 am

Hmmm… I was going to suggest trying to piggyback on the elevator
system’s own motion indicators (often showing current floor position
as well as up/down directional signals), but the problem with the
elevator inspectors would probably put the kibosh on that idea.

Eric Honour

——————-
Associate Professor of Music
Composition and Music Technology
Central Missouri State University


July 12, 2006 | 2:32 pm

Might be a job for RFID. For example:

http://www.makezine.com/blog/archive/2006/05/how_to_homemade_rfid_reader.html

Mount the RFID chips on the shaft, mount the antenna on the elevator.
Chips trigger as the antenna goes by.

– Paul


—– |(*,+,#,=)(#,=,*,+)(=,#,+,*)(+,*,=,#)| —–


July 12, 2006 | 3:30 pm

wonder if a gps receiver could possibly be employed?


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