Alternative Material Speakers

[Dave H]

I find it curious that our new Member posted her question 2 days ago and has never even checked in since ... we posted 10 answers but maybe we are just talking with the rocks

Perhaps it was just publicity for her course?

[rjb]

Perhaps it was just publicity for her course?

According to the linked schedules, classes are already in session.

[tboy]

Perhaps it was just publicity for her course?

I almost put it in the spam folder before anyone responded because I thought it looked fishy (as in fishing for blog traffic). It's possible she hired someone to post links in likely places and doesn't even know it's here herself.

P.S. Her blog has advertising below the fold; probably a pay-per-click thing.

[J M Fahey]

Sometimes new members are slow in keeping up. And the good professor may be keeping busy with her teaching schedule & students' projects. Or she may be put off by - what seem to be - wise guy answers. Although there are valuable things to be found in some of them. In any case, those who wish to post, go ahead. And the rest of us will await some feedback. Meanwhile, on with business as usual.

That would require *reading* them first, wouldnīt it?

[rjb]

P.S. Her blog has advertising below the fold; probably a pay-per-click thing.

Yea, so? When I browse using a system with no ad blocker installed, I see ads at the top of this very forum.
Right now, Feelin'GoodTees.com. More often, some "Date Mature Women" site.
-rb

[tboy]

When I browse using a system with no ad blocker installed, I see ads at the top of this very forum.

Sure, we have ads here, but I don't go around to other sites trolling for extra traffic to come see them.

[Dave H]

I see ads at the top of this very forum.
Right now, Feelin'GoodTees.com. More often, some "Date Mature Women" site.
-rb

I get "Mature Dating" too. Don't the ads you see depend on your browsing habits?

[rjb]

Don't the ads you see depend on your browsing habits?

Could be. I spend way too much time hanging out at "the old mans' club".

[Mark Hammer]

Coils can be made shallow and wide using thin flat neodymiums, and not really be any bigger or heavier than a coat-button. The challenge is attaching the edge of a voice coil to a surface that is stiff enough to provide the sort of piston motion required to move air. In principle, any sort of fabric would not be stiff enough. But I suppose a segment of a larger continuous piece of material could be starched in localized fashion, and provide that stiffer surface.

[eschertron]

I just stumbled across this post by Mick Bailey, which discusses some polymer electro-mechanical action. Could the relationship be reversible, that applying a voltage across a blob of "some kind of polymer" change its shape? Allowing soft, pulsating membranes? They'd probably sound like frying eggs, though. Unless the eggs were being cooked on the PYRO-BOARD!

Of course, this line of thought begs the question, was the original post about "what can I sew into my garments", or was it "what can I spend the next 10 years studying in a lab". For a college course perhaps both are valid, at least for discussion.

[J M Fahey]

Oh, there is such a thing as "piezo film" and it is reversible.

[rjb]

Oh, there is such a thing as "piezo film" and it is reversible.

Last time I checked (which was a few years ago), it could only be purchased in massive quantities.
Some luthier had a blog showing how to build piezo film pickups for archtop guitar, and gave contact info for the film manufacturer. But the manufacturer subsequently stopped selling small quantities. You could find "vibra tab" piezo sensors, but not small sheets of film. Of course, somebody must have some somewhere....

[J M Fahey]

Yes, afaik saddle transducers are being made out of piezo film instead of a piezo ceramic "toothpick" which can easily be cracked; plastic piezo film accomodates better typical uneven saddle cavities.

There used to be also a piezo film tweeter ... what already indicates the possible quality of sound available.

I bet if you make a T Shirt out of it and play some music, voices will sound like chipmunks and drum kits will seem to be made out of cymbals only.

Itīs in full production and datasheet suggests multiple cool uses
http://www.mouser.com/ds/2/261/Piezo...ide-277411.pdf

Accelerometer
ACH-01 (General Purpose)
-Motion (Theft) Sensors
-Shipping Damage
-Machinery Monitoring
-Motional Feedback for Speakers
-Appliance Monitoring
ACH04-08 (Multi-Axis)
-Disc Drive Shock Sensing
-Impact Switching
-Seismic
-Biomedical Monitoring
Vibration/Motion Film Sensor
DT Series (Unlaminated, Unshielded)
-Dynamic Strain Gages
-Acoustic Pickups
-Musical Instrument Triggers
-Tamper Detection
LDT Series (Laminated, Unshielded) & LDTC
-Antitheft Alarm
-Vending
• Dispensing Verification
• Coin Drop Counters
• Antitamper
• Penetration Panels
-Fan Failure
-Application Monitoring
-Washer Imbalance
-Microwave - Sound Pickup
-Dishwasher Spray Arm
-Water Flow Sensor
-Vacuum Soil Sensing
SDT Series (Unlaminated, Shielded)
-Musical Instrument Triggers
-Contact Microphones
Custom Sensors
-Textile Sensors
-Medical Monitoring
• Patient Bed Monitor
• Pulse Counter
• Fetal Heart Monitor
• Apnea Monitoring
• Anesthesia Monitor (Sleep
Disorder)
• Respitory Air Flow
• Sleep Disorder (REM)
• Pacemaker Activity Monitor
-Penetration/Antitamper Panels
• PCMCIA Cards
• Data Storage Devises
MEASUREMENT SPECIALTIES, INC. www.meas-spec.com (757) 766-1500 Fax (757) 766-4297 1
Typiicall Applliicattiions fforr Piiezo Fiillm Sensorrs
Effective: August 1st, 2008
Audio/Acoustic
-Microphones
•Dive Helmets
•Gas Mask
•Contact
-Stethoscope
-Acoustic Pickups
-Flow Sensors
-Speakers
•Novelty Consumer
•Tweeters
•Pagers
Ultrasound (40 kHz & 80 KHz)
-Air-Ranging Proximity
-Medical Imaging Catheters
-Phased Array
-Acoustic Emission
-Level Sensors (Inkjet, toner)
-Robotic Tactile Sensors
-Variable Force Sensors
-Digitizers
Switch
SW100 Series
-Pinball Impact Switches <---
- Gaming Machine Switches <---- these ones for ENZO
- Utility Meter Counters
Custom Switches
-Vector Switch/Joystick
- CMOS Circuit Wake-Up Switch
-Pacinko Game
-Electronic Piano Keys
-Impact Printer Timing Switch
-Sports Target (Impact)
-Snap Action Switches
-Beam Switch
Piezo Cable
-Step Switches
-Pedestrian Safety Mats (Fence & Buried)
-Perimeter Security
-Antitamper
Traffic Sensors
Series BL
-Vehicle Classification
-Weight-in-Motion
-Speed/Red Light Enforcement
-Airport Taxiway
-Security/Safety

They donīt sell small quantities or send free samples but offer "development kits":

Contents of the Basic Design Kit:
This kit demonstrates the
use of MEAS piezo film sensors
as microphones, speakers,
switches and acoustic
pickups. All the components
and film samples in the kit
can be used for experimentation.
This kit demonstrates the
capabilities of piezo film as
a vibration sensor and
accelerometer component.
The kit includes shielded and
unshielded thin film sensors
and an ACH-01 accelerometer
component with an
interface amplifier.

EDIT:

[Reader]

Lots of interesting info in this thread but I'm thinking that the OP's real intention was the posting of click bait.

[nickb]

Lots of interesting info in this thread but I'm thinking that the OP's real intention was the posting of click bait.

Me too. tboy's instinct was right, it would seem.

I guess we got suckered again....