1. COMPASS
PROJECT
Devry Capstone Project:
6/15/2012 How to build, program, and modify
an electronic compass.
Professor: Christine Halsey
Project by Timothy D. Heath
2. Compass Project
This document is intended to explain how to
assemble a compass circuit kit, program the
pic16f72 chip, and modify the circuit board, and
program resulting ina fully functional compass.
TABLE OF CONTENTS
Introduction …………………………………………………………… pg2
Hardware List
a. Compass kit
b. Computer
c. Eblock EB006 programmer board with power supply
d. USB A/B male cable
e. 9v battery
Software List
a. PPP V.3 PIC micro programmer
b. Flowcode
Project Description………………………………………………pg2 , pg3
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3. Compass Project
Assembly and Initial programming
a. Compass kit-
b. Flowcode
c. PPPv3
Modifications
a. Hardware Modifications
b. Software Modifications
Conclusion…………………………………………………………… pg 4
Compass Project
DEVRY CAPSTONE PROJECT:
HOW TO BUILD, PROGRAM, AND MODIFY AN ELECTRONIC
COMPASS.
Introduction
The compass kit is ordered form Devry bookstore, upon delivery all parts were accounted
for. The kit has a compass module that changes resistance depending on orientation to
magnetic north. The signal from the module is then controlled by the program in the
picf72 microchip. After the program has executed a signal is sent to the appropriate LED
light’s on the display.
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4. Compass Project
Hardware List
a. Compass kit
b. Computer
c. Eblock EB006 programmer board with power supply
d. USB A/B male cable
e. 9v battery
Software List
a. PPP V.3 PIC micro programmer
b. Flowcode
Project Description
Assembly and Initial programming
a. Compass kit- the compass kit needs to have all components soldered onto the
circuit board. No schematic is supplied. Student must assemble with
information given which is a parts list and picture of completed board.
Additionally my professor added videos of how to get compass module easily
installed. I made a mistake and installed JP2 connector to the top of the circuit
board when it should have been installed on the bottom. The JP2 connects the
compass circuit to the EB006 programmer. That mistake cost me a lot of time
and I actually damaged several traces on circuit board while correcting this
problem. The damage had to be fixed by soldering an extra wire for each of the
broken traces. I would suggest to anyone assembling this kit to double check
each component before soldering begins.
b. Flowcode-was accessed through Citrix platform and a working program is
available in Doc Sharing tab of course. The original program needs to be
compiled to .hex before it can be used by programming software.
c. PPPv3-I had enormous difficulty getting the correct driver installed and
functioning properly. I went to Matrix Multimedia web site and manually tried
each driver until I found one that worked with a 64bit system. I still had further
difficulties getting the computer to recognize the EB006 board and picf72chip
on board compass circuit. These problems were eventually fixed through trial
and error. The problem would not let me go the normal route defined in the
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5. Compass Project
course description of installation. After resolving problems the process is
simple take the Hex file created in flowcode, select the appropriate chip from
the expert menu, then download program to chip.
Modifications
a. Hardware Modifications- This was fairly simple 3 connections were missing
from circuit board. This was listed on the supplied circuit diagram for the
pic16f72 as pin 11,13, and 14 were labled NC(not connected). These three pins
correspond to port C0,C1, and C2. The LED display also has 3 pins not
connected pin 4, 14, and 15. These unconnected pins on display correspond to
LED M, J, and K. I remedied this problem by soldering the wires onto the circuit
board as follows:
PIC Display
11pin 4pin
13pin 15pin
14pin 14pin
b. Software Modifications- The software modifications were requested to change
the display from its original program of N-E-S-W to an arrow that always
points north. This modification requires the program to be altered by changing
which LED’s are lit up on the display for each respective direction. The display
has ports of PIC program (ports B0-B7 and ports C0-C7) that correspond to
each segment of display which is designated as a letter (A B C D E F g1 H g2 J
K L M N) . A truth table makes quick work of figuring out which port goes to
what segment. The following truth table is a partial representation of how I
programmed the segments to light up.
b7 b6 b5 b4 b3 b2 b1 B0
F H E N G1 A L g2
W1 1 1 1 1 O O O
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6. Compass Project
N0 0 0 1 0 0 1 0
S0 0 0 0 0 1 0 0
C7 C6 C5 C4 C3 C2 C1 C0
D C C1 C2 J K B M
W0 0 0 0 0 0 0 0
N1 0 0 0 0 0 0 1
Conclusion
After completing this project I feel more confident in building, programming, and
modifying a circuit. Of course these things I have already learned from my own
experiences, and previous courses I have completed at Devry. What I more
importantly take away from this class project is improved ability to clearly explain
and demonstrate both process and progress of technical information.
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