Building the Hardware
The most important skills one can have when building a board are the ability to
attend to detail and to solder. I can’t help you with the first, but I can provide some
soldering tips.
Use an iron of about 30 watts with the smallest tip you can find.
Coat the tip of the iron with solder as soon after you plug it in as possible.
Wet a sponge and occasionally wipe the tip on it to keep it shining silver.
To solder a component on the board:
1. Insert the component and push it in so it is flat on the board.
2. Splay the leads so the component won’t fall out.
3. Place the board component side down on the table. For long wire
components, cut the wire to about 1/8”. Don’t worry about cutting leads on
such things as integrated circuits. Their wires are already the correct length.
4. Place the tip of the soldering iron and the solder on the pad to be soldered so
that both are touching the component’s wire.
5. Let the solder flow onto the pad and the wire.
6. As soon as you see the solder coat the whole pad and get on the wire, lift the
soldering iron and solder up from the pad at about the same time, with the
solder slightly leading the iron.
7. Check your work. You should have formed a cone from the pad up on to the
wire. It should be shiny. There should not be a space between the solder and
the wire. The connection should not bridge to an adjacent pad. Use a solder
sucker or a solder wick to remove any bridges.
HOW TO SOLDER, BY
At http://www.epemag.wimborne.co.uk
Soldering is a delicate manual skill which only comes with practice. Remember that your ability to solder
effectively will determine directly how well the prototype or product functions during its lifespan. Poor
soldering can be an expensive business - causing product failure and downtime, engineer's maintenance
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time and customer dissatisfaction. At hobbyist level, bad soldering technique can be a cause of major
disappointment which damages your confidence. It needn't be like that: soldering is really easy to learn, and
like learning to ride a bike, once mastered is never forgotten!
These photos illustrate the basic steps in making a perfect solder joint on a p.c.b. If you're a beginner, our
advice is that it's best to practice your soldering technique using some clean, new parts with perhaps some
new stripboard (protoboard). Be sure to avoid using old, dirty parts; these can be difficult if not impossible
to solder.
EPE published a comprehensive five-part series called "Build Your Own Projects" which shows you how
to construct electronic prototypes, and how to make printed circuit boards, from scratch. It appeared in EPE
November 1996 - March 1997. Check back issues at: htp://www.epemag.wimborne.co.uk/backiss.htm for
more details of availability and prices. Enjoy! Alan Winstanley.
Clean the iron "bit" (tip)
using a damp sponge. Iron
featured is an Ungar
Concept 2100 Soldering
Station.
(Left) A useful product is
Multicore's Tip Tinner
Cleaner (TTC) - a 15
gramme tin of special
paste which cleans and
"tins" the iron, in one go.
(Right) Insert components
and splay the leads so that
the part is held in place.
(Left) It's usually best to
snip the wires to length
prior to soldering. This
helps prevent transmitting
mechanical shocks to the
copper foil.
(Right) Apply a clean iron
tip to the copper and the
lead, in order to heat both
items at the same time.
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(Left) Continue heating
and apply a few
millimetres of solder.
Remove the iron and allow
the solder joint to cool
naturally.
(Right) It only takes a
second or two, to make the
perfect joint, which should
be nice and shiny. Check
the Guide for
troubleshooting help.
(Left) An example of a
"dry" joint - the solder
failed to flow, and instead
beaded to form globules
around the wire.
(Right) "Solder Wick" is a
cheap and very effective
way of desoldering a joint.
Take care not to overheat
the board. Alternatively,
use a desoldering pump.
Small-print: these photos are Copyright © Alan Winstanley 1997. However, you are free to download
them for personal or educational use: help yourself. If you wish to use them for any commercial reasons, all
I ask is that you seek my prior approval first at alan@epemag.demon.co.uk.
For the photographer: the photographs were taken by the author using a Minolta X-700 SLR with 50mm
Minolta MC manual-focus macro lens at f11-16, coupled to a Minolta Auto 80PX macro ring flash gun.
Film was Kodak Gold 200. The prints were scanned using an HP Scanjet 4C flatbed scanner, and enhanced
using JASC Paintshop Pro 4.1 before being uploaded to the EPE web site.
V1.1 Last updated 3rd April 1997
The following is a color code table from the University of Pennsylvania. A resistor is
a device that resists the flow of charge. The unit of resistance is the ohm,
pronounced om with a long o. As you can see, resistors are read by the use of two
significant digit colors, one multiplier and one tolerance color. Think of the
multiplier as the number of 0's stuck on the end. For example, just put 3 0's after
the 27 below. Note that the K stands for kilo or thousand. You will also see Meg in
the instructions. It means million. So brown, violet, green means put down a 4 then
a 7 then 5 0's, or 4700000 which means 4,700,000 or 4.7Meg ohms. To keep things
uniform, it would probably be a good idea to install the resistors with the colors
from left to right or top to bottom in the order of colors shown in the instructions.
The board also uses variable resistors for offset, bass, treble and volume. They
usually have their values printed on them, but can also have a code number that
works like the resistor code. For example, 103 means put a 1 down, then a 0, then 3
more 0's, which gives 10000 ohms or 10K ohms.
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Capacitors are devices which have metal plates separated by an insulator. They are
used to temporarily store an electrical charge. The unit of capacitance is the Farad,
but it's so large that the practice is to use the microfarad, or millionths of a Farad.
Capacitors are labeled many different ways. You will probably find three methods
on the he board. An electrolytic capacitor is usually labeled in plain English, such
as 330MF or 10mf. Electrolytics are also polarized. They have a negative and
positive end and must be installed correctly polarized.
The other capacitors might also be labeled similarly, such as .1MF. It's about as
common however, for them to be labeled with a number code. The .1MF for
example, would be 104. This works like the resistors in that you have a 1 as the first
significant figure, the 0 as the second significant figure and you put 4 0's on the end.
You end up with 100000 picofarads, which is 10E-12 Farads which is one billionth of
a Farad (En means 10 raised to the n). What you end up with is 10E5 * 10E-12 =
10E-7 which is the same as .1MF.
A diode is a device that allows a charge to flow in only one direction. Charge flows
from negative to positive. It's a little like lighting. Lighting travels from a cloud
where there is a greater negative charge to the earth, except near the end of a storm
or in the winter when the earth has accumulated more electrons and is thus more
negative. It then travels up rather than down. The stripe on a diode designates the
cathode or negative end. Thus, a charge can flow through the diode from the
striped end. It can't go the other way.
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The hardware is constructed on a printed circuit board. Its layout is shown below.
Install the components on the board according to the steps on the following pages.
A parts list is at the end of this document.
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STEP 1
Install resistors R1, R2, R3 and R4 in the positions shown, splay
their leads on the back of the board to keep them from falling out,
turn the board over, cut the leads close to the board then solder
them.
R3, 15K
brown, green, orange
R4, 15K
brown, green, orange
R1, 3.9K
orange, white, red
R2, 4.7Meg
yellow, violet, green
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STEP 2
Install R5, R6, R7 and R8 the same way you installed the resistors
in step 1.
R6, 470
yellow, violet, brown
R5, 470
yellow, violet, brown
R7, 10K
brown, black, orange
R8, 10K
brown, black, orange
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STEP 3
Install R9, R10 and R11 the same way you installed the resistors
in step 1.
R11, 150K
R9, 10K
brown, green, yellow brown, black, orange
R10, 3.3K
orange, orange, red
STEP 4
Install D1 and D2 the same way you installed the resistor, except
make sure the stripes are in the correct places.
D2
D1
1N4148 1N4148
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STEP 5
Install the .22MF capacitors C1 and C3 in the positions shown.
Splay their leads on the back of the board to keep them from
falling out, turn the board over, cut the leads close to the board
then solder them to the board.
C3
C1
.22mf .22mf
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STEP 6
Install the two .1MF capacitors C10 and C11 as shown below.
C11
.1MF
C10
.1MF
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STEP 7
Install the two .1MF capacitors, C12 and C13 in a like manner.
C13
.1MF
C12
.1MF
12
STEP 8
Now install the four .1MF capacitors C9, C14, C15 and C16 in a
like manner.
C14
.1MF
C15
.1MF
C16 C9
.1MF .1MF
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STEP 9
Install the .01MF capacitors C4, C5, C6 and C7 as shown below.
C6
C7
C4
C5
.01MF .01MF .01MF .01MF
STEP 10
Install C2, a 10MF electrolytic capacitor. Make sure the negative
end is to the left and the positive to the right.
C2
10MF
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STEP 11
Install C3, a 330MF electrolytic capacitor. Make sure the positive
end is to the left and the negative end to the right.
C8
330 MF
STEP 12
Install VR1, the 10K variable resistor offset trimmer, in the
position shown below.
VR1
10K
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STEP 13
Install the three variable resistors VR2, VR3 and VR4 as shown
below.
VR2
100K
VR3
100K
VR4
10K
STEP 14
Install ARRAY 2 as shown below. Make sure pin 1 is to the right
as shown. It might be shown with a stripe, a number or a dot on
the end.
ARRAY 2
10K, 7 RESISTORS, ONE COMMON
PIN 1
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STEP 15
Please note that the device numbers for the ICs are printed on the
board. While they are shown as 74LS devices, others may be used
that have different prefixes. Just look for the generic part of the
number. For example, a 74LS02's generic would be 74xx02,
where xx could be anything, such as LS, AH, etc.
Install IC1, IC2, and IC5 in the positions shown below. You will
probably need to straighten the pins by rolling the ICs over on their
edges. Be sure to use the correct IC and to get the notches to
the left! Not doing so can destroy not only the board, but your
computer as well! Pin 1 will be the bottom left pin. Splay two
diagonal pins slightly on each to keep them from falling out. Now
tack the diagonals (solder them with just a touch of solder). While
pushing in on an IC from the top of the board, heat each of the pins
you just tacked. The idea is to make sure the IC is snug and flat on
the board. Now solder all leads normally.
IC2
74LS02
IC1
TL074
IC5
DAC0832
STEP 16
Install IC4 using the same methods you did above.
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IC4
ADC0809
STEP 17
Now install IC7 and IC8.
IC7
74LS244
IC8
74LS08
STEP 18
Now install the five ICs, IC9, IC10, IC11, IC12 and IC13 near the
bottom edge of the board.
IC9
74LS393
IC10
74LS138
IC11
74LS688
IC12
IC13
74LS245 LM380N-8
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19
STEP 19
Install the selector switch and jumper 1, a 2 pin header with .1"
spacing between the pins. It might be a little snug. If so, press it
in using a flat metal surface of some sort, such as the flat of a
screwdriver blade. Be sure to install the jumper plug over the
jumper pins. Install the selector DIP switch. The printing should
be oriented the same as the ICs.
Jumper 1
Switch 1 (readable same as ICs)
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STEP 20
Install Jack 1 for the microphone and Jack 2 for the speaker.
J2 Speaker Output
J1 Mike Input
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STEP 21
Install IC6, a DAC0832, the second digital to analog converter.
IC6
DACO832
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STEP 22
Install IC3, header 1 and header 2. IC3 is the Programmable
Peripheral Interface. The headers have .1" spacing between pins
and between rows.
IC3
Header 2
Header 1
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STEP 23
The final step is to install ARRAY1, header 3 and header 4. This
completes construction of the hardware.
HEADER 4
HEADER 3
ARRAY 1, PIN 1
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Parts Needed For Digital Experiments
(These will get you started. I priced them at $18.65, mostly from Jameco .)
Capacitors
C9, C10, C11, C12, C13, C14, C15,
C16
.1MF .2", or 5mm spacing, anything above 12 volts OK, ceramic
OK
Resistor Arrays or Networks
ARRAY1
9 resistor, 10 pin 10K SIP with one end of each resistor commoned to pin 1
ARRAY2
7 resistor, 8 pin 10K SIP with one end of each resistor commoned to pin 1
DIP Switch
SW1
Three Position DIP Switch
Headers -- All have two rows .1" apart with pins .1" apart
HEADER 1
2 X 8 pin header
HEADER 2
2 X 5 pin header
HEADER 3 and 4
2 X 13 pin headers
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Integrated Circuits -- 74, 74HCT, 74AHC, etc. prefixes may be substituted for 74LS
IC2
74LS02 quad NOR gate
IC3
8C255 Programmable Peripheral Interface
IC7
74LS244 octal buffer
IC8
74LS08 quad AND gate
IC9
74LS393 counter
IC10
74LS138 1 of 8 decoder
IC11
74LS688 digital comparator
IC12
74LS245 octal transceiver
Additional Parts Needed For Remaining Experiments
(I priced these parts at about $24.00, mostly from Jameco .)
Variable Resistors
VR1
10K OFFSET TRIMMER (25 turn) equal to Bourns type 3296X
VR2
100K BASS TRIMMER equal to Bourns type 3386C
VR3
100K TREBLE TRIMMER equal to Bourns type 3386C
VR4
10K VOLUME TRIMMER equal to Bourns type 3386C
Capacitors
C1, C3
.22MF .2" or 5mm spacing film similar to Panasonic
ECQ-V1H224JL
C2
10MF 25v axial electrolytic similar to Panasonic
ECE-B1EU100S
C4, C5, C6, C7
.01MF .2" or 5mm spacing film similar to Panasonic
ECQ-V1H103JL
C8
330MF 6.3v axial electrolytic similar to Panasonic
ECE-B0JU331
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Jumper
JP1
.1" Header Type Jumper
Diodes
D1, D2
1N4148 switching diode
IN/OUT CONNECTORS
J1, J2
Switchraft 1/8" phone jack -- Mouser Electronics # 16PJ528
Resistors -- All Are 1/8 Watt
R1
3.9K
R2
4.7M
R3, R4
15K
R5,R6
470
R7,R8,R9
10K
R10
3.3K
R11
150K
Integrated Circuits
IC1
TL074 or LF347A quad op amp
IC4
ADC0809 8 input, 8-bit AD converter
IC5, IC6
DAC0832 8-bit DA converter
IC13
LM380N-8 power amp (8 pin DIP version)
PARTS SOURCES
A
AAA The Bottom Line Surplus
Alltronics
All Electronics Corp
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Allied Electronics
Avnet Electronics
Alpha & Omega Electronics Surplus Electronics
ATMEL
B
Byers Chassis Kits
C
Chip directory
Circuit Specialists
Capital Electronics
Complete Computer Solutions, Inc
Computer & Computer Engineering Resources, by Category, Ramey Corporation
Computer Liquidations, LTD
D
Digi Key
E
EIO Electronics Surplus
Electrical Engineering Vendors
electroBASE
listing of distributors, representatives, services, and component manufacturers
Electronet
Electronic Parts Data Base
Electronic Component Distributors
Electronic Surplus Electronics Components
Electronics Bookmark -- Some Resources
Electronics PARTS SUPPLIERS List
Electronics Surplus -- DW Elect
Electronix Express
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Excess, Surplus Electronics Directory
F
FaradNet Home Page
Futurlec Electronic Components
G
Gray's Brief Semiconductor URL Page
H
Harry Krantz Company
HSC Electronic Supply
I
J
Jameco Electronics
JDR Micro Electronics
K
Kelvin Electronics
MECI Electronics
M.C. Howard Electronics
Maxim
Mitel Semiconductor
MX-COM
Miscellaneous links
Mondo-tronics' Robot Store
Mouser Electronics
Mushroom Components
N
National Semiconuctor
Nerd World Electronic Components
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Newark
New, used, and surplus computer equipment
Norm's Industrial Electronics Component Manufacturers
Now! Components Ltd
Provides an eCommerce service for buyers and sellers of electronic components.
Nuts & Volts Magazine
O
Oatley Electronics - Links To Other Sites
Q
Quality Kits On-Line Catalog
"We offer a wide selection of electronic kits for the beginner or more advanced projects
for the electronics expert. Quality Electronic kits from Maplin Electronics, Velleman - kit
and DIY Electronics."
R
R & D Electronics
RadioShack
Ramsey Electronics
Rich's Surplus Electronics Warehouse
S
Semicon Internet Information System
Surplus Al's
Surplus - clearance sales - liquidations
Surplus Direct
Surplus Electronic Parts G-G Enterprises
Surplus Electronic Parts -- Telepath
Surplus Electronic Source List
Surplus Electronics Market
Surplus Traders - 750 Page Computer and Surplus
Switchcraft
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T
Tandy Corporation Home Page
Tanner Electronics
Tech America
TI Logic Home Page
COMPILER, ASSEMBLER AND DEBUGGER
MIX Software
1132 Commerce Drive
Richardson TX 75081
(800) 333-0330 (orders only)
(214) 783-6001 (other)
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Printed Circuit Boards
Lower quantities of bare, silk-screened, solder-masked boards with gold-plated
edge-board connectors can be purchased from me for $20 each, postage paid. I'll
even sell you a complete board with the expanded capabilities for $75 if that's
what you want, although I'd rather hear of people (especially youth)making their
own. A kit consisting of a board and parts is $50. Texas residents, please don't
worry about the tax -- I'll pay it -- how many times have you seen that?
Joe Reeder
1455 N. Perry #1205
Carrollton TX 75006
You can save if you need greater quantities of bare boards:
QUANTITY
1 to 4
5 to 14
15 to 24
25 to 49
50 to 99
100 to 249
250 to 499
500 to 999
1000 Up
PRICE EACH
$20.00
$18.90
$18.65
$18.45
$18.35
$18.30
$17.50
$17.15
$16.75
One way to pay is through PayPal on the site. As a bonus, they offer $5 just to sign up.
That means a single bare board only costs you $15!
Shipping:

within 24 hours for 20 or fewer boards if paid with PayPal, money order or cashier's check

2 to 3 weeks for quantities between 20 and 100 if paid with PayPal, money order or cashier's
check

3 to 4 weeks for kits if paid with PayPal, money order or cashier's check

4 to 6 weeks for quantities greater than 100, for assembled boards or if payment is made with a
check
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