Elenco Electronics K-28 User guide

POCKET DICE KIT
MODEL K-28
Assembly and Instruction Manual
Copyright © 2005, 1989 byElenco®Electronics,Inc. All rights reserved. Revised 2005 REV-D 753228
No partof this book shall be reproduced byanymeans; electronic, photocopying, or otherwise without written permission from the publisher.
Elenco®Electronics, Inc.

PARTS LIST
If you are a student, and any parts are missing or damaged, please see instructor or bookstore.
If you purchased this pocket dice kit from a distributor, catalog, etc., please contact Elenco®Electronics
(address/phone/e-mail is at the back of this manual) for additional assistance, if needed. DO NOT contact your
place of purchase as they will not be able to help you.
RESISTORS
Qty. Symbol Value Color Code Part #
r6 R2,4,5,6,8,9 1.2kW5% 1/4W brown-red-red-gold 141200
r2 R3, R7 1.5kW5% 1/4W brown-green-red-gold 141500
r1 R1 100kW5% 1/4W brown-black-yellow-gold 161000
CAPACITORS
Qty. Symbol Value Description Part #
r1 C1 .01mF Discap 241031
SEMICONDUCTORS
Qty. Symbol Value Description Part #
r1 D19 1N4001 Diode 314001
r4 D15 - D18 1N4148 Diode 314148
r1 IC1 4011 Integrated Circuit 334011
r2 IC2, IC3 4018 Integrated Circuit 334018
r14 D1 - D14 LED (red) 350002
MISCELLANEOUS
Qty. Symbol Description Part #
r1 PC Board 518028
r1 S1 Switch push button 540001
r1S2 Switch Slide 541102
r24” Solder 551124
r1 B1 Battery Snap 9V 590098
r1IC1 IC Socket 14-pin 664014
r2IC2, IC3 IC Socket 16-pin 664016
-1-
Resistor
PARTS IDENTIFICATION
Capacitor
Diode
LED
Integrated Circuit
IC Socket
Push Button Switch Slide Switch
Battery Snap

-2-
IDENTIFYING RESISTOR VALUES
Use the following information as a guide in properly identifying the value of resistors.
BAND 1
1st Digit
Color Digit
Black 0
Brown 1
Red 2
Orange 3
Yellow 4
Green 5
Blue 6
Violet 7
Gray 8
White 9
BAND 2
2nd Digit
Color Digit
Black 0
Brown 1
Red 2
Orange 3
Yellow 4
Green 5
Blue 6
Violet 7
Gray 8
White 9
Multiplier
Color Multiplier
Black 1
Brown 10
Red 100
Orange 1,000
Yellow 10,000
Green 100,000
Blue 1,000,000
Silver 0.01
Gold 0.1
Resistance
Tolerance
Color Tolerance
Silver +10%
Gold +5%
Brown +1%
Red +2%
Orange +3%
Green +.5%
Blue +.25%
Violet +.1%
BANDS
12 Multiplier Tolerance
IDENTIFYING CAPACITOR VALUES
Capacitors will be identified by their capacitance value in pF (picofarads), nF (nanofarads), or mF(microfarads). Most
capacitors will have their actual value printed on them. Some capacitors may have their value printed in the following
manner. The maximum operating voltage may also be printed on the capacitor.
Second Digit
First Digit
Multiplier
T
olerance The letter M indicates a tolerance of +20%
The letter K indicates a tolerance of +10%
The letter J indicates a tolerance of +5%
For the No. 01234589
Multiply By 1 10 100 1k 10k 100k .01 0.1
Multiplier
Note: The letter “R” may be used at times
to signify a decimal point; as in 3R3 = 3.3
103K
100V
Maximum Working Voltage
The value is 10 x 1,000 = 10,000pF or .01mF100V
10mF 16V
Abbreviation Means Multiply Unit By Or
p Pico .000000000001 10-12
nnano .000000001 10-9
mmicro .000001 10-6
m milli .001 10-3
– unit 1 100
k kilo 1,000 103
Mmega 1,000,000 106
1. 1,000 pico units =1nano unit
2. 1,000 nano units = 1 micro unit
3. 1,000 micro units = 1 milli unit
4. 1,000 milli units =1unit
5. 1,000 units = 1 kilo unit
6. 1,000 kilo units = 1 mega unit
METRIC UNITS AND CONVERSIONS

-3-
Dice are the most ancient gambling implement
known to man, and the most universal, having been
known in nearly all parts of the world since earliest
times. Today they are used in some games of skill,
such as backgammon, but are used chiefly in
gambling games. In the United States the most
popular dice game is Craps.
Each die consists of seven light emitting diodes
(LEDs). Since there are two dice, we need 14
LEDs. The trick is to light the right LEDs to give the
six possible dice combinations.
The Pocket Dice kit consists of three main circuits.
They are (1) a clock oscillator, (2) a presettable
counter and (3) a decoder circuit.
Figure 1 shows a block diagram of the functions.
We will study each function and get an
understanding on how the Pocket Dice kit works.
Referring to Figure 1, the clockputs out a series of
pulses at about 60 per second. The counter IC2
receives the clock pulses and outputs 0’s or 1’s on
pins 4, 5 and 6. The outputs can represent anyone
of six combinations 000, 001, 010, 110, 111 or 101.
Each time the clock puts out a pulse, the output of
the counter changes. The 0’sand 1’sare fed to the
decoder circuit which transforms the 0 and 1
combinations into a series of lit LEDs to displaythe
die patterns. Pin 13 of IC2 changes state once
every time the IC passes through the six state
sequence. Thus, it puts out a pulse at a frequency
of one-sixth of the digital clock or 10 pulses per
second. This signal is fed the input of IC3 and
becomes its clock input. IC3 and its decoder work
the same as IC2 except at a slower clock rate.
THE CLOCK FUNCTION
Figure 2 shows the diagram of the clock circuit. It
consists of two NAND gate digital integrated
circuits. In our circuit, the two inputs are tied
together which forms an inverter circuit. When the
input of IC1A is low, the output will be high, thus
when the input of IC1B is high, its output will be low.
This output is fed to the input of IC1A via capacitor
C1 and is called positive feedback, a key element to
make a circuit oscillate. The frequency of oscillation
depends on the value of capacitor C1 and resistor
R1. The value chosen results in a frequency of
approximately 60 cycles per second. The output at
IC1B will be a square wave.
In the Pocket Dice
kit, we want the
oscillator to run for a
short time. As long
as the oscillator is
running, the dice
will be constantly
changing numbers.
The number changes once with every cycle, or 60
times per second. For the dice to come up with a
number, we must stop the clock. This is done by
shorting out the feedback with switch SW1. Once
the switch is closed, the clock will stop and a
random number will appear on the dice.
THE PRESETTABLE COUNTER FUNCTION
IC2 and IC3 are the presettable counters. These
counters convertthe clock pulses in six
combinations of “1” and “0”. These IC’shave a
single input at pin 14 and three outputs on pins 4, 5
and 6. With everypulse change at the input, the
output will change as shown in Figure 3. Note the
corresponding dice number as the result of the 0
and 1 output of pins 4, 5 and 6.
By tying pin 6 to pin
1, we programmed
the counter to put out
only 6 combinations
as shown in Figure 3.
Every time the clock
puts out a pulse, the
counter will change
its output. On the
first pulse, the
counter pins 4 and 5
will be low (0) and pin
6will be high (1).
This results in the die number two. The next clock
pulse will result in the counter output of all lows (0)
and the die will show the number one. Thus, the
sequence continues until all six numbers are shown.
CIRCUIT DESCRIPTION
INTRODUCTION
Figure 1
Figure 2
Figure 3
456
001
000
010
110
111
101
Output Pins
Clock Pulse
1
2
3
4
5
6
First Die Second Die
IC2 IC3
Counter 1 Counter 2Clock
Decoder 1 Decoder 2
4 5 6 4 5 6
IC1
A
IC1
B
R1
C1S1

The next pulse will repeat the process with two
showing on the die.
The output of IC2 also drives IC3. This results in
IC3 output changing in step with IC2, but at a slower
rate.
THE DECODER CIRCUIT
The decoder circuit takes the output of the
presettable counter and lights the correct LEDs.
Figure 4 shows the decoder circuit. It consists of a
NAND gate and an OR gate. The OR gate is formed
by two diodes. The purpose of the decoder circuits
is to “decode” the outputs of pins 4, 5 and 6 of IC2
or IC3 to light the correct LEDs. The truth tables for
the NAND and the OR gates are shown in Figure 5.
They show the output C versus the inputs A and B.
Thus, if the inputs of the NAND gate are both low
(0), the output will be high (1).
Figure 6 shows the wiring of the LEDs to the NAND
and OR gates output. Note that when IC pin 10 is
low, LED D2 and D1 will light. Also, when pin 5 or 6
of IC2 are high, LEDs D4 and D5 will light. Figure 7
shows which LEDs are being lit as a result of the
outputs of pin 4, 5 and 6 of IC2 or IC3.
Let’s go through a couple of decodings to see how
it works. Refer to Figures 6 and 7. Remember an
LED will light when the cathode is low and the
anode is high as shown in Figure 8.
When the die displays a one, only LED D3 will light.
For this to happen, output pin 4, 5 and 6 or IC2 will
have to go low (0) and the following will result.
1) D3 turns on as its cathode will be low.
2) The input of the NAND gate is low therefore its
output will be high. D2 and D1 will not light.
3) The input of the OR gate is low, so its output
will be low. Thus, D4 and D5 will not light.
4) Pin 4 of IC2 is low, therefore LED D6 and D7
will not light.
Let’s try another number - 3. Here we must light
LEDs D3, D4 and D5. The output of pin 4 is low, pin
5and pin 6 low (0, 1, 0).
1) Pin 6 is low, therefore LED D3 will light.
2) Pin 5 is high, Therefore the outputs of the OR
gate will be high, lighting LED D4 and D5.
3) Pin 4 is low, therefore LEDs D6 and D7 will not
light.
4) The inputs of the NAND gate are high and low,
therefore the NAND gate output will be high
and LEDs D1 and D2 will not light.
Try to figure out the other four patterns. It actually
can be fun.
-4-
Figure 4 Figure 5
Figure 7
Figure 8
ABC
0 0 1
1 0 1
0 1 1
1 1 0
A B C
0 0 0
1 0 1
0 1 1
1 1 1
NAND OR
4 5 6 LEDs Lit
Die Number
1 1 1 D4, D1, D7, D6, D2, D5 Six
1 1 0 D4, D7, D6, D5, D3 Five
1 0 1 D4, D7, D6, D5 Four
0 1 0 D4, D3, D5 Three
0 0 1 D4, D5 Two
0 0 0 D3 One
Pins on IC2
NAND Gate
OR Gate
Figure 6
IC2
9
8
5
6
4D7 D6
D5 D4
D2 D1
D3
10
D16
D15
+
Current
Limiting
Resistors
Input High
Input Low
0V
9V
Lit
Not Lit

-5-
Introduction
The most important factor in assembling your K-28 Pocket Dice Kit is good soldering techniques. Using the
proper soldering iron is of prime importance. A small pencil type soldering iron of 25 - 40 watts is
recommended. The tip of the iron must be kept clean at all times and well tinned.
Safety Procedures
• Wear eye protection when soldering.
•
Locate soldering iron in an area where you do not have to go around it or reach over it.
•Do not hold solder in your mouth. Solder contains lead and is a toxic substance. Wash your hands
thoroughly after handling solder.
• Be sure that there is adequate ventilation present.
Assemble Components
In all of the following assembly steps, the components must be installed on the top side of the PC board unless
otherwise indicated. The top legend shows where each component goes. The leads pass through the
corresponding holes in the board and are soldered on the foil side.
Use only rosin core solder of 63/37 alloy.
DO NOT USE ACID CORE SOLDER!
CONSTRUCTION
Solder Soldering Iron
Foil
Solder
Soldering Iron
Foil
Component Lead
Soldering Iron
Circuit Board
Foil
Rosin
Soldering iron positioned
incorrectly.
Solder
Gap
Component Lead
Solder
Soldering Iron
Drag
Foil
1. Solder all components from
the copper foil side only.
Push the soldering iron tip
against both the lead and
the circuit board foil.
2. Apply a small amount of
solder to the iron tip. This
allows the heat to leave the
iron and onto the foil.
Immediately apply solder to
the opposite side of the
connection, away from the
iron. Allow the heated
component and the circuit
foil to melt the solder.
1. Insufficient heat -the
solder will not flow onto the
lead as shown.
3. Allow the solder to flow
around the connection.
Then, remove the solder
and the iron and let the
connection cool. The
solder should have flowed
smoothly and not lump
around the wire lead.
4. Here is what a good solder
connection looks like.
2. Insufficient solder -let the
solder flow over the
connection until it is
covered. Use just enough
solder to cover the
connection.
3. Excessive solder -could
make connections that you
did not intend to between
adjacent foil areas or
terminals.
4. Solder bridges -occur
when solder runs between
circuit paths and creates a
short circuit. This is usually
caused by using too much
solder. To correct this,
simply drag your soldering
iron across the solder
bridge as shown.
What Good Soldering Looks Like
Agood solder connection should be bright, shiny,
smooth, and uniformly flowed over all surfaces.
Types of Poor Soldering Connections

ASSEMBLE COMPONENTS TO THE PC BOARD
Figure C
Mount the diode with
the band in the same
direction shown on PC
board.
Band
S2 - Slide Switch
B1 - Battery Snap 9V
(see Figure D)
J3 - Jumper Wire
(see Figure A)
D19 - 1N4001 Diode
(see Figure C)
IC2 - 16-pin Socket
IC2 - 4018 Integrated Circuit
(see Figure B)
R3 - 1.5kW5% 1/4W Resistor
(brown-green-red-gold)
J4 - Jumper Wire
(see Figure A)
R2 - 1.2kW5% 1/4W Resistor
(brown-red-red-gold)
D16 - 1N4148 Diode
D15 - 1N4148 Diode
(see Figure C)
R5 - 1.2kW5% 1/4W Resistor
(brown-red-red-gold)
R4 - 1.2kW5% 1/4W Resistor
(brown-red-red-gold)
S1 - Push Button Switch
J5 - Jumper Wire
J6 - Jumper Wire
(see Figure A)
C1 - .01mF(103) Capacitor
IC3 - 16-pin Socket
IC3 - 4018 Integrated Circuit
(see Figure B)
R7 - 1.5kW5% 1/4W Resistor
(brown-green-red-gold)
J1 - Jumper Wire
(see Figure A)
D17 - 1N4148 Diode
D18 - 1N4148 Diode
(see Figure C)
R6 - 1.2kW5% 1/4W Resistor
(brown-red-red-gold)
R1 - 100kW5% 1/4W Resistor
(brown-black-yellow-gold)
IC1 - 14-pin Socket
IC1 - 4011 Integrated Circuit
(see Figure B)
R8 - 1.2kW5% 1/4W Resistor
(brown-red-red-gold)
R9 - 1.2kW5% 1/4W Resistor
(brown-red-red-gold)
J2 - Jumper Wire
(see Figure A)
-6-
Figure A
Use a discarded resistor lead
for a jumper wire. Bend the
wire to the correct length and
mount it to the PC board.
Figure B
Insert the IC socket into the PC
board with the notch in the
direction shown on the top
legend. Solder the IC socket into
place. Insert the IC into the
socket with the notch in the same
direction as the notch on the
socket. Figure D
Mount the battery snap
to B1 on the PC board
as shown below with
the red wire in the (+)
hole and the black wire
in the (–) hole.
Socket
IC
PC Board
Red Wire
BlackWire

-7-
TROUBLESHOOTING
Contact Elenco®Electronics if you have any problems. DO NOT contact your place of purchase as they will not
be able to help you.
D1 - LED (red)
D2 - LED (red)
D3 - LED (red)
D4 - LED (red)
D5 - LED (red)
D6 - LED (red)
D7 - LED (red)
(see Figure E)
D8 - LED (red)
D9 - LED (red)
D10 - LED (red)
D11 - LED (red)
D12 - LED (red)
D13 - LED (red)
D14 - LED (red)
(see Figure E)
ASSEMBLY CONTINUED
Figure E
Mount the LED with the flat
side in the same direction as
marked on the PC board.
1. One of the most frequently occurring problems is
poor solder connections.
a) Tug slightly on all parts to make sure that
they are indeed soldered.
b) All solder connections should be shiny.
Resolder any that are not.
c) Solder should flow into a smooth puddle
rather than a round ball. Resolder any
connection that has formed into a ball.
d) Have any solder bridges formed? A solder
bridge may occur if you accidentally touch
an adjacent foil by using too much solder or
by dragging the soldering iron across
adjacent foils.Break the bridge with your
soldering iron.
2. Be sure that all components have been mounted
in their correct places.
a) Be sure that diodes D15-D19 have not been
installed backwards. The band on the
diodes should be in the same direction as
shown on the top legend.
b) Be sure that LEDs D1-D14 have not been
installed backwards. The flat side on the
LEDs should be in the same direction as
shown on the top legend.
c) Have the ICs been inserted into their
sockets correctly? The notch or dot on the
ICs should be in the same direction as
shown on the top legend.
d) Be sure to use a fresh 9-volt battery.
Flat
Mount flush
with PC board
Foil Side of PC Board

CRAPS
Players: Any number from two and up. The
players bet amongst themselves. In gambling
houses, the players are grouped around a large
table resembling a billiard table, stenciled with a
layout shown where bets should be placed and what
odds are paid.
The Play: The player who starts the game places
in the center whatever he wishes to bet and
announces its amount. Any other player or players
may fade such portions of the bet as they wish, by
placing that amount in the center with the shooters
bet. Any part of the bet not faded is withdrawn by
the shooter. No more than the amount offered may
be faded.
The shooter rolls the dice. The shooter wins if his
first roll is a 7 or 11 (a natural). He loses if it is a 2,
3or 12 (craps); he has a point to make if it is a 4, 5,
6, 8, 9 or 10. When he gets a point, the result is not
yet decided. He must roll them again and again, as
often as necessary, and he will win if his point
appears before a 7, but he will lose if a 7 appears
first. All intervening rolls are meaningless.
When the shooter loses, those who faded him take
such part of the center bets as belong to them
(always exactly double the amount they bet, for all
center bets are at even money). When the shooter
wins (passes) all of the money in the center belongs
to him and he may make another center bet if he
wishes, increasing or decreasing his previous bet as
he sees fit, but no one is ever forced to bet, and he
may give up the dice if he prefers.
The shooter loses the dice when he gets a point and
fails to make it. In this case, or when he voluntarily
passes the dice, the player at his left becomes the
next shooter.
-8-
QUIZ
1. How many pulses per second does the clock circuit
output?
rA. 10
rB. 25
rC. 60
rD. 2
2. The output of the counter can be one of _________
combinations.
rA. 100
rB. 6
rC.30
rD. 200
3. What type of logic gate is IC1?
rA. OR
rB. AND
rC. XNOR
rD.NAND
4. The frequency of the clock circuit depends on the value
of capacitor C1 and _________.
rA. diode D1.
rB. IC2.
rC. resistor R1.
rD. LED D3.
5. How many of IC2 outputs pins are used.
rA. 3
rB.5
rC. 1
rD. 4
6. By tying pin 6 to pin _____, we program the counter to
output only _____ combinations.
rA. 14,8
rB. 2, 5
rC. 13, 7
rD. 1,6
7. The OR gate in the circuit is formed by two _________.
rA. resistors.
rB. LED’s.
rC. diodes.
rD. capacitors.
8. What die number lights up if pins 4 and 5 are high and
6is low on IC2?
rA. two
rB. nine
rC. five
rD.one
9. Each die consists of how many LED’s?
rA. 10
rB. 7
rC. 12
rD. 10
10. The output of the clock circuit produces a _________
wave.
rA. triangle
rB.ramp
rC. saw
rD. square
Answers: 1) C; 2) B; 3) D; 4) C; 5) A; 6) D; 7) C; 8) C; 9) B; 10) D

-9-
DEFINITION OF TERMS
Capacitor An electrical component that can store electrical pressure (voltage) for periods of time.
Color Code Amethod for marking resistors using colored bands.
Digital Circuit Awide range of circuits in which all inputs and outputs have only two states, such as
high/low.
Diode An electronic device that allows current to flow in only one direction.
Disc Capacitor
Atype of capacitor that has low capacitance and is used mostly in high frequency circuits.
Farad, (F) The unit of measure for capacitance.
Feedback To adjust the input to something based on what its output is doing.
Frequency The rate at which something repeats.
Ground Acommon term for the 0V or “–” side of a battery or generator.
Integrated Circuit Atype of circuit in which transistors, diodes, resistors, and capacitors are all
constructed on a semiconductor base.
Kilo- (K) A prefix used in the metric system. It means a thousand of something.
LED Common abbreviation for light emitting diode.
Leads The wires sticking out of an electronic component, used to connect it to the circuit.
Light Emitting Diode Adiode made from gallium arsenide that has a turn-on energy so high that light is
generated when current flows through it.
Meg- (M) A prefix used in the metric system. It means a million of something.
Micro- (m
m)A prefix used in the metric system. It means one millionth (0.000001) of something.
Milli- (m) A prefix used in the metric system. It means one thousandth (0.001) of something.
NAND Gate A type of digital circuit which gives a HIGH output if some of its inputs are LOW.
NOR Gate A type of digital circuit which gives a HIGH output if none of its inputs are HIGH.
Ohm, (W
W)The unit of measure for resistance.
OR Gate A type of digital circuit which gives a HIGH output if any of its inputs are HIGH.
Oscillator A circuit that uses feedback to generate an AC output.
Printed Circuit Board A board used for mounting electrical components. Components are connected using
metal traces “printed” on the board instead of wires.
Resistance
The electrical friction between an electric current and the material it is flowing through;
the loss of energy from electrons as they move between atoms of the material.
Resistor Components used to control the flow of electricity in a circuit. They are made of carbon.
Schematic A drawing of an electrical circuit that uses symbols for all the components.
Semiconductor A material that has more resistance than conductors but less than insulators. It is
used to construct diodes, transistors, and integrated circuits.
Series When electrical components are connected one after the other.
Short Circuit When wires from different parts of a circuit (or different circuits) connect accidentally.
Solder A tin-lead metal that becomes a liquid when heated to above 360 degrees. In addition
to having low resistance like other metals, solder also provides a strong mounting that
can withstand shocks.
Switch A device to connect (“closed” or “on”) or disconnect (“open” or “off”) wires in an
electric circuit.
Voltage A measure of how strong an electric charge across a material is.
Voltage Divider A resistor configuration to create a lower voltage.
Volts (V) The unit of measure for voltage.

SCHEMATIC DIAGRAM
-10-

Elenco®Electronics, Inc.
150 Carpenter Avenue
Wheeling, IL 60090
[phone]
Fax: [phone]
Website: www.elenco.com
e-mail: [e-mail]