David Covick wrote:

> There are many other sources.

> essentially it is a small 1.3 volt motor with a weight on the shaft
> that is "off-balance", this causes the low frequency vibration

> You could make one up quickly with any motor and weight.

  But much easier to buy a pager motor complete with the weight.

  There is another big market for them outside the pager field too.
Many, many, many sites on the 'Net...  :))
--
  Cheers,
        Paul B.