Download Circuit Board Fabrication Project Sheet

Circuit Board Fabrication Project
TEL 240 - Electronics Technology
Name:_______________________
What you will be able to do:
• Etch a printed circuit board from prepared artwork.
• Prepare the circuit board for component population
• Assemble and solder a circuit board
• Test the completed circuit for proper function
Project Description:
You will be creating a circuit board that will
play a basic game. This circuit board
contains a Microchip PIC Microprocessor
that has been programmed with PicBasic to
play a Simon Says game. The circuit board
contains LEDs as outputs, pushbutton
switches for inputs, a piezoelectric speaker,
and the clock circuitry to drive the
microprocessor.
In this project, you will create the circuit
board from basic artwork, assemble the
circuit, program the microprocessor, and test
the circuit.
Finished Simon Board
Printed Circuit Board Project
Grade Worksheet
Criteria
Circuit Board Artwork Transferred Properly
Circuit Board Etched Properly
Circuit Board is Drilled Properly
Components Mounted Properly
Good Solder Joints
Circuit Functions Properly
Safety practices used
TOTAL
Value
15
15
15
15
15
15
10
100
Student Grade
Instructor Grade
Part I – Circuit Board Artwork Preparation
Materials
Required
Task to
complete
PC Board Material
Thermal Laminator
Toner Transfer Artwork
Safety Glasses
Step 1 – Toner Artwork Transfer
1. Cut a piece of copper clad board to a finished size of 2 ½” x 2 ½”
2. Clean the surface of the copper with steel wool. Do not touch the surface
with your fingers. Residual oils and dirt will prevent the toner resist from
sticking properly resulting in a bad board.
3. Preheat the laminating press.
4. Obtain a copy of the circuit artwork from the instructor. Avoid touching
the surface with your fingers. Residual oils and dirt will prevent the toner
resist from sticking properly resulting in a bad board.
5. Carefully align the PC board material on the artwork with the black artwork
in contact with the copper. Feed the board and artwork through the
laminator twice.
6. Place the board and carrier under a steel plate and allow the board to cool
for a few minutes.
7. Place the board in a pan of warm water. Be sure that it is completely
covered with water. Allow the board to soak for 2 to3 minutes without
disturbing it. The paper should separate from the board without assistance.
8. Remove the board from the water without touching the copper. Inspect the
board. If the artwork is intact, you can continue on to the next step. If
patches of the artwork did not stick, you will need to repeat the steps above.
Part II – Circuit Board Etching
Materials
Required
Prepared PC Board with Artwork
Etch Tank with Ferric Chloride
Safety Glasses
Rinse Water
Task to
complete
Safety Warning: You will be using a Ferric Chloride Solution to
chemically etch the copper clad board. Ferric Chloride is a mild acid
that can hurt you. The following safety rules must be followed:
•
•
•
•
•
•
•
•
•
•
•
Safety Glasses must be worn at all times when working around the Ferric
Chloride.
Avoid breathing fumes from the etch tank.
Do not attempt to operate the tech tank with the lid open.
Do not handle or place on benches or counters circuit boards or tools that
have Ferric Chloride on them.
Rinse all tools and circuit boards thoroughly with water for 2 to 3 minutes
to remove any residual ferric chloride.
If Ferric Chloride comes in contact with your skin or clothing, you must
rinse the Ferric Chloride off with water.
Avoid touching your face or eyes after working with the Ferric Chloride
until you have thoroughly washed.
Clean up any drips or spills.
Leave the workspace clean and in order after working in the etching
process.
Ferric Chloride leaves stains that are difficult to remove from clothes.
Wear a lab coat or older clothes when completing this activity
Report any problems to the instructor immediately!
Failure to follow any of these safety precautions will
result in losing etching privileges and receiving a
grade of Zero on this project.
Etching Process:
1. Fill out the Etch Tank use log.
2. Tape your circuit board to the glass board holder using a loop of masking
tape on the back. The copper should be facing out.
3. Place the board holder inside of the etch tank. Make sure that the etch tank
cover is in closed.
4. Start the etching machine. Check the board after 1 minute to see if it is
done. If it is not, return it to the etch tank and etch it for 30 second
increments after that.
5. When the board is fully etched, remove the board carrier from the etch tank
and place it directly in the rinse tank using plastic tongs. Rinse it in water
for 3 minutes.
6. Remove the carrier and the board and place them in the sink. You may
remove the circuit board from the carrier. Rinse them both thoroughly with
water. Be careful of coming in contact with any residual Ferric Chloride
that may be behind the board or in the tape.
7. Remove the plastic toner from the surface of the copper using steel wool.
8. Clean up the work area and wash your hands. Get the approval of the
instructor for clean up on the Etch Tank use log.
Part III – Drilling and Board Preparation
Materials
Required
Drill Press
#58 Drill
#68 Drill
1/8” Drill
File
Safety Glasses
Task to
complete
Safety Warning: Safety Glasses must be worn when using the drill
press.
1. Using the diagram provided, drill the holes in the circuit board to the correct
sizes.
2. Cut the circuit board corners off following the lines left by the toner
transfer.
3. Using a file, clean up any rough or sharp edges on the circuit board.
Part IV – Circuit Assembly
Materials
Required
Components for Circuit Board
Component
Microchip PIC 12F683 Microprocessor
(not included in kit)
7805 Voltage Regulator (TO-92)
8 Pin IC Socket
0.1µF Capacitor
Piezoelectric Speaker
Red LED
1 KΩ Resistor
10 KΩ Resistor
Pushbutton Switch
Battery Clip
1/4" 4-40 Machine Screw and Nut
Printed Circuit Board (not in kit)
Transfer Paper
TOTAL
QTY
1
1
1
1
1
4
4
4
4
1
2
1
1
Cost Each
Total Cost
$
$
$
$
$
$
$
$
$
$
$
$
$
$
$
$
$
$
$
$
$
$
$
$
$
$
$
1.12
0.27
0.14
0.09
0.80
0.09
0.01
0.01
0.13
0.35
0.10
0.85
0.13
1.12
0.27
0.14
0.09
0.80
0.36
0.04
0.04
0.52
0.29
0.20
0.80
0.13
4.80
Task to
complete
Safety Warning: Safety Glasses must be worn when using the soldering
iron.
1. Place the 1KΩ resistors in the circuit board. They should be oriented to be
right-reading from the bottom or right side of the board. Solder these in
place. Trim off the excess leads.
2. Place the 10KΩ resistors in the circuit board. They should be oriented to be
right-reading from the bottom or right side of the board. Solder these in
place. Trim off the excess leads.
3. Insert the 8 Pin IC socket into the circuit board. Make sure that the notch
that indicates which end has pin 1. Solder each of the pins in place.
4. Insert the LEDs into the board. This needs to be oriented with the anode (+)
(longer lead) toward the outside of the board. Solder these in place. Trim
off the excess leads.
5. Insert the 0.1µF capacitor into the circuit board. Solder this in place. Trim
off the excess leads.
6. Insert the leads for the 7805 voltage regulator into the circuit board and
solder them in place. The flat should face away from the 8 pin socket.
7. Insert the leads for each of the pushbutton switches into the circuit board.
Solder the leads in place and trim them off.
8. Insert the leads for the Piezo speaker into the circuit board. The speaker has
a positive and negative lead. Make sure to put the positive lead toward the
bottom of the board.
9. Inspect the circuit board for cold joints and solder bridges. Make any
repairs if necessary.
10. Test the circuit board by connecting 9VDC to the board at your workstation.
The LEDs should turn on when the buttons are pushed, even without the
microprocessor.
11. If the board works, connect the battery clip. Bend the leads to be in
alignment with the bottom of the clip. Connect the clip to the circuit board
with two 4-40 x ¼” screws and nuts. Solder the two wire leads to the
rectangular power pads.
12. You are ready to program the microprocessor. Follow the separate
directions to do the programming.
Part V – Programming the Microprocessor
Materials PIC 12F683 Microprocessor
Required PIC Basic and Microprocessor Programmer
1. On a classroom computer, open the program on the desktop: MicroCode Studio. Download the
PicSimon program from the instructor’s website (www.oswego.edu/~hardy) to your computer’s
desktop. Go to File => Open => and open the file from your desktop.
2. Optional: Once the program is opened, you can create you own sequence. Locate the area in the
program that with the double bars top and bottom that looks like the following:
Initialize EEPROM Values
' Note that the game sequence can be changed by changing the values in
' the following lines. Each set of brackets must contain 32 numbers.
' Only 0,1,2,4 are allowed. Separate numbers with commas.
EEPROM
EEPROM
EEPROM
EEPROM
0,[0,4,2,1,4,0,1,0,4,2,1,4,0,1,4,0,2,1,4,2,1,0,2,1,0,4,2,0,1,1,0,4]
32,[0,1,0,4,2,1,4,0,1,4,0,2,1,4,2,1,0,2,1,0,4,2,0,1,1,0,4,4,1,2,4,2]
64,[0,4,2,1,4,0,1,4,0,2,1,4,2,1,0,2,1,0,4,2,0,1,1,0,4,2,1,4,2,1,0,2]
96,[0,1,4,0,2,1,4,2,1,0,2,1,0,4,2,0,1,1,0,4,1,2,1,4,2,1,0,2,1,0,4,2]
Replace the sequence of numbers that you used with the numbers in the parentheses following the
EEPROM command. Note the following:
a. Put in only 32 numbers in each bracket set.
b. Place a comma between each number
c. Only used values of 0,1,2,4
d. Do not change any other part of the program
3. To program compile the program, select from the menu bar Project => then Compile and Program.
4. The programmer application will open. Insert your microprocessor into the programmer. Make
sure that pin 1 is toward the left as marked on the programmer. Make sure that the programmer
lists the PIC12F683 microprocessor as the one being programmed. Click on the menu option
Program => Program. The chip will take about 20 seconds to program and verify. When
completed, carefully remove the chip and place it in your own circuit board and test it.
5. Place the programmed chip into your game board. When power is turned on, the LEDs should turn
on and off in a continuous loop. Press any button to start the game. Repeat the sequence provided
by the game. If you miss a sequence the game will end, Phasers will fire, and the game will give
you your score as a binary number.
Verify that
this box has
the
16F627A
chip
selected