Path: utzoo!utgpu!jarvis.csri.toronto.edu!rutgers!uwm.edu!cs.utexas.edu!oakhill!craig
From: craig@oakhill.UUCP (Craig Shaw)
Newsgroups: sci.electronics
Subject: Re: hardware info needed
Summary: Motor with eccentric will vibrate
Keywords: Vibration, motor, tiny
Message-ID: <3013@sol.oakhill.UUCP>
Date: 23 Feb 90 18:50:26 GMT
References: <1990Feb22.185504.15032@ncsuvx.ncsu.edu>
Reply-To: craig@sol.UUCP (Craig Shaw)
Distribution: usa
Organization: Motorola Inc., Austin, Texas
Lines: 23

In article <1990Feb22.185504.15032@ncsuvx.ncsu.edu> safrit@shumv1.ncsu.edu (John Safrit) writes:
>
>	I'm presently working on a research project that requires the output of
>a bandpass filter to be converted to a vibration that can be felt on the skin.
>I've used small speakers, but they don't produce a strong enough vibration.  
>

 Try a small permanent-magnet DC motor with an eccentric on the shaft. I
believe that is what is used on my pager, when it is operated in silent mode.
Ideally the RPM should be tuned to the resonant frequency of the enclosure.

 The entire pager runs off of 1 AA battery, and is about 2 1/2" x 1 1/2" x
3/4". It also has an 12+ character LCD display, which even lights up!
The heart of the system is a 68HC11 microcontroller. At about 3 pages/day
the battery life is better than three months (Eveready alkaline).

 The point is, this can be done small, cheap, and low-power.

					Good luck.
-- 

I'M THE NRA.
Craig D. Shaw - MCU Systems Design (512)891-2245  Motorola Inc., Austin, TX.