Page 168 - Making PIC Microcontroller Instruments and Controllers

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The answer to this question is neither simple nor short.
Firstf Almosl all the instirmenls you need dre ,rot aNailable otf the sheA. Morc acar-
rately stated, only bits and pa s of the insmrments you requir€ a1e avaiiable. The instru-
ments we will build will be more useful than their generic off-the-shelt' siblings, and in
some ways are more specifically targeted 10 &e task at hand. Since we lnow exacdy what
we need, we will design an instrxment that provides cxact\ what we want. We do nol have
to compromise on any prope(y of the inslxment. Also, our instruments will be able to
provide other inlelligence functions, like turning other laboratory equipmenl on and off
as needed by our experimenls, and as determined by the condilions the insirument is
monitoring in real time. This is a vsry useful feature almost never lbund on an ind slfial
instrument, but that is absolutely essenlial if we want to autonute our prccesscs.
Second: We will be able to automalically scnd the information bei g galhercd to a
compulcr for analysis, either in real time or on a defbr.ed basis depending oD whal our
overall needs are, We can al so gathef a lot more infbrmation over a longer period of time
with our custom instruments beca se we will now have the ability to automate the
process. Transient phenomcna that require constant monitoring ovet long periods of time
and produce only in a few important instances can now be monitorcd continuously and
intelligently without concem or added expense.
Third: Our instruments willbe able to make intelligent decisions in real time. Ifdata
points that are unexpected or extraordinary are encountered, the instrument can call
this to our attention so remedial or special (even human) attention can be given to the

Fourth: Or the outpul side, the ability to turn pumps, fans, healers, and the like on
and off automaticnlly, based on lhe information sensed by the instrument cannot be dis-
missed our of hand. Very lew oft:the shelf volt-/ohmmeters can tum an ancjllary piece
of equipment on or off at a given voltage. Most do not even have an oulput that we could
connect to if we so desired. However, wilh our custom designed instrumenls, it will be
easy, Few ohmmelers can send the value read to a computu every second or every hour.
jt
But with the insfuments we will build, will be easy. No olf ihe-shelf i nshxmertu can
be reprogrammed inBASIC with one click ofthe mouse. With lhe instruments that we
will create, however, this will be the case. The instruments we shall design and build
will be intimately familiar to us, so moditying them will be relatively easy. Once the
input-output appurtemnces have been decided on and connected to the microcontroller,
the rest will be controlled by the software we will write. llwe feel the instrumenl is not
responding the way wc want it to. we can modify it with minimal effort.
Fiffh: Specialized instruments can often be made for a lot less than you may thinkl
Si\tht vouwilldevelop critical skillsyou ca use the rest o^'orr lifu. This in itselfmight
b,r more important than anything else. (After all, wc live in the information age, no?)
We can say with some confidence that with a liltle learning and efforl on our part,
wc arl] can create insiuments lailored to our necds that will help us be morc produc-
live. (And in the process make our lives more inferesting.)
So what kinds of things can be sensed easily? We need to know what we can sensc
because what we sense will bc the data source we feed into our microcontroller-based
instrumentcontroller.