Elenco Pocket Dice User Manual

POCKET DICE KIT

MODEL K-28

Assembly and Instruction Manual

Copyright © 2014, 1989 by Elenco®Electronics, Inc. All rights reserved. Revised 2014 REV-H 753228

No part of this book shall be reproduced by any means; electronic, photocopying, or otherwise without written permission from the publisher.

ELENCO

®

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

®

(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 #

! 6 R2,4,5,6,8,9 1.2kΩ 5% 1/4W brown-red-red-gold 141200
! 2 R3, R7 1.5kΩ 5% 1/4W brown-green-red-gold 141500
! 1 R1 100kΩ 5% 1/4W brown-black-yellow-gold 161000

CAPACITORS

Qty. Symbol Value Description Part #

! 1 C1 .01µF Discap 241031

SEMICONDUCTORS

Qty. Symbol Value Description Part #

! 1 D19 1N4001 Diode 314001
! 4 D15 - D18 1N4148 Diode 314148
! 1 IC1 4011 Integrated Circuit 334011
! 2 IC2, IC3 4018 Integrated Circuit 334018
! 14 D1 - D14 LED (red) 350002

MISCELLANEOUS

-1-

Resistor

PARTS IDENTIFICATION

Capacitor

Diode

LED

Integrated Circuit

IC Socket

Push Button Switch

Slide Switch

Battery Snap

● Do not short circuit the battery terminals.

● Never throw the battery in a fire or attempt to

open its outer casing.

●

Use only 9V alkaline battery (not included).

● Insert battery with correct polarity.

● Non-rechargeable batteries should not be

recharged. Rechargeable batteries should
only be charged under adult supervision, and
should not be recharged while in the product.

● Remove battery when it is used up.

● Batteries are harmful if swallowed, so keep

away from small children.

Batteries:

Qty. Symbol Description Part #

! 1 PC Board 518028
! 1 S1 Switch push button 540001
! 1 S2 Switch Slide 541102

Qty. Symbol Description Part #

! 1 B1 Battery Snap 9V 590098
! 1 IC1 IC Socket 14-pin 664014
! 2 IC2, IC3 IC Socket 16-pin 664016

-2-

Warning:

If the capacitor is
connected with
incorrect polarity, it
may heat up and
either leak, or
cause the capacitor
to explode.

IDENTIFYING RESISTOR VALUES

Use the following information as a guide in properly identifying the value of resistors.

BANDS

METRIC UNITS AND CONVERSIONS

Abbreviation Means Multiply Unit By Or

p Pico .000000000001 10

-12

n nano .000000001 10

-9

µ micro .000001 10

-6

m milli .001 10

-3

– unit 1 10

0

k kilo 1,000 10

3

M mega 1,000,000 10

6

1. 1,000 pico units = 1 nano unit

2. 1,000 nano units = 1 micro unit

3. 1,000 micro units = 1 milli unit

4. 1,000 milli units = 1 unit

5. 1,000 units = 1 kilo unit

6. 1,000 kilo units = 1 mega unit

IDENTIFYING CAPACITOR VALUES

Capacitors will be identified by their capacitance value in pF (picofarads), nF (nanofarads), or µF (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.

Electrolytic capacitors have a positive
and a negative electrode. The
negative lead is indicated on the
packaging by a stripe with minus
signs and possibly arrowheads. Also,
the negative lead of a radial
electrolytic is shorter than the positive
one.

Polarity
marking

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

Tole rance

Color Tol eran ce

Silver ±10%
Gold ±5%
Brown ±1%
Red ±2%
Orange ±3%
Green ±0.5%
Blue ±0.25%
Violet ±0.1%

1

2 Multiplier Tolerance

Multiplier

For the No. 0 1 2 3 4 5 8 9

Multiply By 1 10 100 1k 10k 100k .01 0.1

(+)

(–)

(+)

(–)

Axial

Radial

Second digit

First digit

Multiplier

Tolerance*

Note: The letter “R” may be used at times
to signify a decimal point; as in 3R3 = 3.3

The letter M indicates a tolerance of +20%
The letter K indicates a tolerance of +10%
The letter J indicates a tolerance of +5%

Maximum working voltage

(may or may not appear
on the cap)

The value is 10 x 10 =
100pF, +10%, 50V

*

CERAMIC DISC MYLAR

First digit

Second digit

Multiplier

Tolerance*

2A222J

100V

The value is 22 x 100 =
2,200pF or .0022µF, +5%, 100V

101K

50V

-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 clock puts 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 any one
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’s and 1’s are fed to the
decoder circuit which transforms the 0 and 1
combinations into a series of lit LEDs to display the
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 convert the clock pulses in six
combinations of “1” and “0”. These IC’s have a
single input at pin 14 and three outputs on pins 4, 5
and 6. With every pulse 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
6 will 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. The next pulse will

CIRCUIT DESCRIPTION

INTRODUCTION

Figure 1

Figure 2

Figure 3

4 5 6
0 0 1
0 0 0
0 1 0
1 1 0
1 1 1
1 0 1

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