The case of the Sharp module must be _WELL_ grounded for one thing.
If not, it tends to false trigger frequently.  Unless we are talking about
different modules, the Sharp modules I have experimented with were very
forgiving as long as they saw the near infrared light from the kind of
LED's commonly used in remotes and the carrier frequency was
within a KHZ or so of 32,767 HZ.  The range and quality of the received
data go right down to nothing if the carrier frequency is off.  If it is
way off such as 40 or 50 KHZ, you may get brief triggers from the Sharp
module, but it won't follow the carrier.

        In one case, I took a 33 KHZ generator I had built and gated it with
a square-wave signal generator and began raising the frequency of the
generator.  The output of the IR module tracked the square wave pretty well
until I reached about 2,000 HZ at which time the Sharp receiver began to
falter.  I must admit that this test was not very scientific in that I
simply listened to the output on a speaker as I cranked up the frequency
and noted the point when it got rough and noisy which occurred rather quickly
above about 2 KHZ.

        Most IR remotes we had lying around the house made the Sharp module
respond with the kind of range typical of such things, so it shouldn't be
too tricky to get it to work as long as the carrier frequency is right.

Martin McCormick