Your question sounded like it could be a fun topic, so I decided to respond.
Overall, I think the answer to this question would be very dependent upon what
you wanted to accomplish.  That is, there would typically be some performance
expectation, such as whether you wanted to just jump once, how high, how often,
and is there anything that the jump is expected to accomplish that also
constitutes a performance expectation.  Depending upon the answers to these
questions, the answers could be very different.

Years ago, Edmund Scientific offered a small quarter-sized device that would
jump some time after being placed on a table.  Then you had to "click" it back
into another position and set it down again before it would jump again.  You
could purchase just one, or several (or many), and I noticed that they generally
had varying response times.  I suspect that they were also temperature
dependent.  So, depending on what you wanted, this kind of approach might make
sense, with a microactuator slowly putting the necessary potential energy into
the system, and some other action triggering it so that the jump occurred.

Robert S Wegeng

        -----Original Message-----
        From:   Dylan Bryant [SMTP:dylan@mgtsciences.com]
        Sent:   Wednesday, March 04, 1998 1:25 PM
        To:     MEMS@ISI.EDU
        Subject:

        Fellow MEMS-ers,
                I have a question for anyone who is so inclined to answer:
                In reference to micromachining, what would be the best way to
get
                a microchip or a MCM to "jump"? What I mean is, if I had a small
                module that I wanted to propell in an upward manner, would a
small
                spring mechanism do the job? I know lots of variables come into
play,
                such as the module's weight, the spring constant and how high I
want
                the thing to go; but all this is mainly trivial.  I guess I'm
just
                trying to figure out if anyone has pondered the same question
before,
                and if anyone has, then what became of it?  If anyone has any
info or
                ideas, feel free to respond!

                Dylan P. Bryant
                Engineering Research Assistant
                Management Sciences, Inc.
                & UNM School of Engineering
                Mechanical Engineering, Dept.
                dylan@mgtsciences.com

                Ciao!