Page 183 - Making PIC Microcontroller Instruments and Controllers

THE ErcHr 'ECHtl|OIEo lilg

modules added. Later on in Proiect 13.7. we will convert this instrument into a con
trollet and then in Project 13.8 we will use it to log fhe data ftom a solar collec|or
over an extended period. It is important to understand that the two quantities con-
sidered do not have to be the same thing. We could use the linear brightness of a light
to control the pambolic speed of a motor by putting the information though a custom_
designed controller
5.In the artificial hodzon project, we leam how to use pulsed signals read from a
sensor to contol the position of a table positioned with 1wo model aircraft servos.
The seNos arc fed signals that are a flrnction of the eror signal read from the sensor
and hold the table iII a hodzontal position.
6. Building the touch screen is the basis for leaming about scanning routines. Though
this is a relatively small surface, we can demonsuate and leam about the lechniques
used to make a touch screen with this project. A touch screen is a control panel you
can make on the laboratory bench with minimal cost and cffo(
7. The two-input controller is a finished instrument that incor?orates the competencies
learned in the previously mentioned projects. We then use this insFument in the next
project to create a data logger
g, Data logging is covered in the context of a solar collector aDd uses the two-input con-
foller to provide the data that we then ]og over an extended period of time auto-
matically. The dala will be sent to a personal computer for storage and go through
eventual analysis at a later date.

Adding a little nore detail tothepreceding descriptions, we willdiscuss, then build,
and hopefully understand the engineering and science behind the following eight
projects.

l. THE BASICS OF COUI'ltl G PULSES:
THE IACHOMETER PROJECT
Research has indicated that carefully managing the engine speed as you drive around
town can substantially increase the efficiency of your automobile. Design and build an
inexpensive tachometer that can be added to an automolive engine wilh minimal effon.
Design rhe device to display the engine rpm (revolutions per minute) on a four-digit
display. The display and the CPU board are to be placed at some convenient location
in ftont of the driver The system most use the I2 dc power available on the automo-
bile and sta when the ignition switch is tumed on.
This is an exercise in counting pulses that come in at vanous rales, and dispiaying
theresults on seven segmentdisplays oron an LCD. Almosf all the sigoalswe use wilh
microprocesso$ end up havjng to do with counting and nanipulating pulses, so this is
a core comperency you musr master

2. THE METRONOIIIE! CREATING CO TROLLED PULSES

Ms. Music, our local high school music teacher, did not get the funding lbr the metronomes
she wanted for her class. The principal has asked your electonics instructor so see ifhe/she
can qet the class to create 25 low-cost netmnomes lbr the music students.