Elenco Electronics SNAP CIRCUITS SKILL BUILDER User manual

1
PROJECTS
1-57
MANUAL
58-126
ONLINE
INSTRUCTION
MANUAL
AGES
8+
Copyright © 2021 by Elenco®Electronics, Inc. All rights reserved. No part of this book shall be reproduced by any means; electronic,
photocopying, or otherwise without written permission from the publisher. U.S. Patents: 7,144,255; 7,273,377 & patents pending SOURCE CODE: SB-125V1
753124WEB
REV-A

2
TABLE OF CONTENTS
Click through our table of contents to nd
the projects you want to build!
Project 58-59 p. 1
Project 60-69 p. 2
Project 70-79 p. 6
Project 80-89 p. 10
Project 90-99 p. 13
Project 100-109 p.18
Project 110-119 p.21
Project 120-126 p.26
Project Cut Outs p.30
2

1
Project 58 Lift Loss
Build the circuit to the left.
Cover the photoresistor (RP) and turn on the slide switch (S1).
The motor (M1) should spin. If not, give it a push to get it started.
Now uncover the photoresistor or get a ashlight and shine it on
the photoresistor. The motor will slow down as more light reaches
the photoresistor, and will stop spinning if enough light reaches the
photoresistor. This circuit demonstrates how darkness can be used
to control a fan. Try this circuit with and without the fan on the motor.
Project 59 Laser Blaster
This circuit demonstrates
how sounds can be made
for electronic games.
Build the circuit shown on the left.
When you turn on the slide switch (S1), the integrated circuit (U2)
should start sounding a laser gun sound. This integrated circuit is
designed to produce different sounds that can easily be changed. You
can even switch the sound on and off quickly to add sound effects to
your games or recordings.
WARNING: Moving parts. Do not touch the fan
or motor during operation.

2
Mind Reader Game
Build the circuit below. It uses a paper clip and a
3-Snap Wire as “shorting bars”.
Setup: Player 1 sets the target by placing the
3-snap shorting bar under the paper on column
2, 3 or 4. Player 2 must NOT know where the
shorting bar is located under the paper.
The object is for Player 2 to guess the location by
placing one end of the paper clip on the 5-snap
wire as shown, and the other end of the paper clip
at positions X, Y, or Z and then pressing the press
switch (S2). If Player 2 places the paper clip at
the correct position, the sounds played indicates
a “hit”. He keeps guessing until he hits. After each
hit, remove the 3-snap shorting bar and slide the
switch off and on to reset the sound.
Player 2 then sets the 2, 3, 4 side and player 1
tries his luck.
Play multiple rounds and see who gets the best
overall score. The winner will be the player who is
best at reading his opponent’s mind.
Paper Sheet to
hide position of
shorting bar
Project 60

3
Don’t Make a Sound
Use the circuit from Project 60, but now place a 3-snap wire and the
LED (D1) as “shorting bars” under the paper sheet as shown on left.
Setup: Player 1 sets the “Quiet Zone” by placing the 3-snap wire
and the LED (D1) under the paper on columns 2, 3 or 4, leaving only
one open. Player 2 must NOT know where these “shorting bars” are
located under the paper.
Both Player 1 and Player 2 are given 10 points. The object is for
Player 2 to guess the location of the “Quiet Zone” by placing the paper
clip at positions X, Y, or Z and pressing the press switch. If Player 2
places the paper clip on the correct column, and a sound plays when
he presses the press switch, this means he has not found the “Quiet
Zone” and he loses 1 point. He has three (3) tries to nd the zone on
each turn. Each time sounds are made he loses a point.
Player 2 then sets the 2, 3 or 4 side and player 1 starts searching. Play
continues until one player is at zero points and makes sound during
that players turn.
Discover the Diode
Diodes are electronic components that allow current to ow in only one
direction, blocking it in the other. The red LED (D1) is a special diode
that can emit light, and the transistor (Q1) can also be used as a pair
of diodes.
Turn on the slide switch (S1), the lamp (L1) will be bright and the
LED (D1) will be lit. The NPN transistor (Q2) is used here as a diode,
allowing the batteries to charge up the 470 mF capacitor (C5) and light
the LED.
Turn off the slide switch, the lamp will go dark immediately but the LED
will stay lit for a few moments as capacitor C5 discharges through it.
The transistor/diode isolates the capacitor from the lamp.
Project 61
Project 62
Paper sheet
to hide
position of
shorting bar

4
Mixed Up Music
Snappy says there sure are a lot of
different sounds that can be made
with the music and alarm ICs.
In the circuit, the outputs from the alarm and
music ICs are connected together. Build the
circuit shown and then place the alarm IC (U2)
directly over the music IC (U1), resting on two
1-snaps and a 2-snap. Turn on the switch (S1)
and you will hear a siren and music together
while the lamp (L1) varies in brightness.
Modify the last circuit by connecting points Y & Z with a 2-snap (on
level 5). The circuit works the same way but now it sounds like a
machine gun with music.
Project 64 Blaster Disaster
Now remove the 2-snap connection between Y & Z and then make
a 2-snap connection between X & Y (on level 5). The circuit works
the same way but now it sounds like a re engine with music.
Project 65 Siren & Song
Now remove the 2-snap connection between X & Y and then make
a 2-snap connection between W & X (on level 5). The circuit works
the same way but now it sounds like an ambulance with music.
Project 66 Ambulance Song
Project 63

5
Fuse or Lose
When you close the slide switch (S1), current ows from the batteries
through the slide switch (S1), the lamp (L1), motor (M1), and back to
the battery (B1). Pretend the 2-snap wire marked fuse in the drawing
on the left is a device that will open the circuit if too much current is
taken from the battery. When press switch (S2) is closed, the light is
shorted and motor speed increases due to an increase in current to the
motor. While still holding press switch (S2) down, remove the 2-snap
wire marked fuse and notice how everything stops. Until the fuse is
replaced, the open circuit path protects the electronic parts. If fuses did
not exist, many parts could get hot and even start res. Replace the
2-snap wire and the circuit should return to normal.
Many electronic products in
your home have a fuse that will
open when too much current is
drawn. Can you name some?
Space Battle
Build the circuit shown on the left. Turn on the switch (S1) and you will
hear exciting sounds, as if a space battle is raging!
The motor (M1) is used here as a 3-snap wire, and will not spin.
The preceding circuit is loud and may bother people around you,
so replace the speaker (SP) with the LED (D1). Make sure you
connect the LED with the positive (+) side on A6, not U3. Now you
have a silent space battle.
Project 68 Bizzare Blinker
Project 69
Project 67
WARNING: Moving parts. Do not touch the fan
or motor during operation.

6
People that are deaf need lights to tell them
when a doorbell is ringing. They also use
circuits like this to tell them if an alarm has
been triggered or an oven is ready.
Can you think of other uses?
Different sounds that can easily be
changed are very important when
designing games and toys.
Wave & Watch
This circuit does not use the noisy speaker (SP) but instead uses a
nice quiet LED (D1). Turn on the slide switch (S1), the LED ickers.
Wait a few seconds, and then cover the photoresistor (RP), and the
icker stops. The icker is controlled by the photoresistor; uncover it
and the icker resumes.
Switching Sounds
Build the circuit shown on the left. When you close the slide switch (S1),
the integrated circuit (U2) should start sounding an up-down siren. This
is just one more sound effect that this integrated circuit is designed to
produce. Switch the sound on and off quickly and see if you can create
even different effects. This mode will create many robotic sounds if
switched quickly.
Project 70
Project 71

7
Transistors use a small current to
control a large current, and have three
connection points (the small current,
the larger current, and the combined
current). But they are actually
constructed using two diodes that are
connected together. These diodes
are similar to your LED (light emitting
diode) except that they don’t emit light.
Turn on the switch (S1), the LED
(D1) and lamp (L1) are bright.
This is an unusual circuit which
uses the NPN transistor (Q2) as
two connected diodes to split the
current from the batteries into the
paths with the LED and lamp. If
the LED (D1) does not light, you
may have weak batteries in need
of replacement.
This circuit has four different
types of output. Flip the switch
(S1) several times. The LED (D1)
and lamp (L1) light up, the motor
(M1) spins, and the speaker
(SP) makes a siren sound. If
the LED does not light, you may
have weak batteries that need
replacement.
This is an unusual circuit which
uses the NPN transistor (Q2) as
two connected diodes, to split
the current from the batteries
(B1) into the paths with the LED
and lamp.
The speaker uses electromagnetism to create
changes in air pressure, which your ears feel
and interpret as sound. Think of the speaker
as creating pressure waves in the air just
like waves in a pool. You only see waves in
the pool when you disturb the water, so the
speaker only makes sound when the voltage
changes.
Pop On, Pop Off
Turn the slide switch (S1) on and off several times. You hear static
from the speaker (SP) when you turn off the switch.
Project 72 Project 73
Project 74
WARNING: Moving parts. Do not touch the fan
or motor during operation.
Current Splitter Light Up & Listen

8
Project 76
Little to Big
Place the fan on the motor (M1) and turn on the slide switch (S1), then compare
this circuit to Project #31. Push the press switch (S2), the lamp doesn’t light now
but the motor still spins.
The lamp is dark because the 100Wresistor (R1) limits the current through it. The
NPN transistor (Q2) uses the small lamp current to create a large current that spins
the motor.
Now replace the 100Wresistor (R1) with the larger 1KWresistor (R2). The motor
spins more slowly now, because the transistor cannot create as large of a motor
current from such a small controlling current.
The lamp is dark because the
photoresistor limits the current
through it. The NPN transistor uses
the small lamp current to create a
large current that spins the motor.
If you tried to control the motor speed
by placing the photoresistor in series
with the motor, the motor would not
spin because the photoresistor would
limit the current. But the photoresistor
can control the motor speed with help
from the transistor. You may need to
shine a light on the photoresistor (RP)
if the motor does not spin.
Compare this circuit to Project 75. It uses the
photoresistor (RP) to control the current to
the NPN transistor (Q2), instead of the press
switch (S2). You can adjust the speed of
the motor (M1) by changing how much light
shines on the photoresistor.
The motor doesn’t spin because the
100Wresistor (R1) limits the current
through it. The NPN transistor (Q2)
uses the small motor current to create
a large current that lights the lamp.
Now replace the 100Wresistor (R1)
with the larger 1KWresistor (R2). The
lamp is only slightly less bright even
though the motor current is much
lower.
Now place the 100Wresistor back in
the circuit and replace the press switch
with the photoresistor (RP). A bright
light on the photoresistor will turn the
lamp on. But if the light is dim, then
the photoresistor has high resistance,
so little current ows through the
transistor and the lamp is off.
Compare this circuit to Project 23. Push the
press switch (S2), the motor (M1) doesn’t
spin now but the lamp (L1) still lights.
Project 75
Project 77
WARNING: Moving parts.
Do not touch the fan or
motor during operation.
WARNING: Moving parts. Do not touch the fan or
motor during operation. Do not lean over motor.
Fan may not rise until switch is released.
Transistors, such as the NPN transistor (Q2), can amplify
electric currents. In this circuit, the small current through the
resistor is used to control a larger current through the motor. A
large resistor value limits the current through the lamp, making
it very dim, but the transistor amplied current is large enough
to still spin the motor.
Light to LightLuminate & Rotate

9
Music Reflection Detector
How good of a reector is a black piece of
paper? Tin foil? How about your hand?
Reflection Detector
Build the circuit to the left. Place it where there won’t be any room light
hitting the photoresistor (RP) (such as in a dark room or under a table),
and then turn it on. The 2.5V lamp (L1) will be bright, but there should
be no sound.
Take a small mirror and hold it over the lamp and photoresistor. You
should hear sound now. You have a reection detector! You can also
use a white piece of paper instead of a mirror, since white surfaces
reect light.
Build the circuit to the left. Place it where there won’t be any room light
hitting the photoresistor (RP) (such as in a dark room or under a table),
and then turn it on. The 2.5V lamp (L1) will be bright, and one song
may play, but then there should be no sound.
Take a small mirror and hold it over the lamp and photoresistor. You
should hear sound now. You have a music reection detector! You
can also use a white piece of paper instead of a mirror, since white
surfaces reect light.
Project 78
Project 79

10
This circuit demonstrates how
toy laser guns can be designed.
Laser Flasher
When you press the press switch (S2), the integrated circuit should
start sounding a very loud laser gun sound. The red LED will ash
simulating a burst of laser light. You can shoot long repeating laser
burst, or short zaps by tapping the press switch.
Flash & Flicker
Build the circuit shown on the left, which uses the Space War integrated
circuit.
Set the switch on and the speaker makes exciting sounds. The output
of the IC can control lights, speakers, and other low power devices.
You may replace the speaker (SP) with the 2.5V lamp (L1), and the
bulb will icker. You can also use the LED (D1) in place of the lamp
(position it with the “+” side towards the 6-snap).
Project 80
Project 81
This circuit demonstrates how
continuous laser gun sounds
can be generated.

11
Spinning Rings
Setup: Cut out the disc on page 29 that looks like the one shown here.
Using Scotch tape, attach the disc with the printed side up on the top
of the fan blade. Place the blade on the motor as shown to the left
and below.
When the press switch (S2) is pressed, the arcs will turn into colored
rings with a black background. Notice how the color drops in brightness
when it is stretched to make a complete circle.
Use the circuit from Project 82.
Setup: Place the spinning rings under a uorescent light that runs
on normal house current. Start the disc spinning and release the
press switch (S2). As the speed changes you will notice the white
lines rst seem to move in one direction then they start moving in
another direction. This effect is because the lights are blinking 60
times a second and the changing speed of the motor is acting like a
strobe light to catch the motion at certain speeds. To prove this, try
the same test with a ashlight. The light from a ashlight is constant
and if all other lights are out, you will not see the effect that looks
like a helicopter blade in a movie. Some uorescent lights use an
electronic ballast and they also produce a constant light.
Project 83 Strobe the House Lights
Project 82
WARNING: Moving parts. Do not touch the fan
or motor during operation.

12
This circuit would make a good night light.
It would allow you to get into bed, and
then it would go out. No further current is
taken from the battery so it will not drain
the batteries even if left on all night.
Project 84
Modify Project 82 by adding the pointer as shown on the left. The paper should be
cut from page 30 and taped high enough on the speaker so the pointer will stick
over the fan with paper. Bend the pointer at a right angle as shown on the left.
Setup: Cut out the grid with four (4) colors from page 30 and place it under the
base as shown on the left. Each player picks a color (or two colors if only 2 people
are playing) and places a single snap on row G. The purple player in column 1,
the blue player in column 2, the green player in column 3, and the yellow player
in column 4. Spin the wheel by closing the press switch (S2). The rst single color
wedge that the pointer points to is the rst player to start. In some models you only
have three 1-snaps, so use a 2-snap if you have four players.
The Play: Each player gets a turn to press the press switch. They release the
press switch and when the pointer points to a wedge, the players that match the
colors on the wedge get to move up one space. If a liner comes up like the one
shown on the left then the players on each side of the line get to move up two (2)
spaces. The rst player to reach the top row (A) wins. If two players reach the top
row at the same time they must both drop down to row “D” and play continues.
Race Game
Project 85
Build the circuit to the left. When you turn on the slide switch (S1) the rst
time the LED (D1) will come on and very slowly get dimmer and dimmer.
If you turn the slide switch (S1) off and back on after the LED goes out it
will NOT come on again. The 470mF capacitor (C5) has charged up and
the NPN transistor amplier (Q2) can get no current at its input to turn
it on. To discharge the capacitor (C5) and reset the circuit, press and
release the switch (S2).
Auto-Off Night Light
WARNING: Moving parts. Do not touch the fan
or motor during operation.

13
The photoresistor contains material that
changes its resistance when it is exposed to
light. As it gets more light, the resistance of
the photoresistor decreases. Parts like this
are used in a number of ways that affect our
lives. For example, you may have streetlights
in your neighborhood that turn on when it
starts getting dark and turn off in the morning.
Visual Volume
Build the circuit shown on the left.
Turn on the slide switch (S1), a police siren is heard. The loudness of the
sound depends on how much light reaches the photoresistor (RP). Try
partially shielding it or placing near a very bright light, and compare the
sound.
Modify the last circuit by connecting the photoresistor to points
A & X. The circuit works the same way but now it sounds link an
ambulance when enough light reaches the photoresistor.
Project 87 Daylight Alarm
Now remove the photoresistor from points A & X and connect it to
points C & Z. The circuit works the same way but now it sounds
like a machine gun when enough light reaches the photoresistor.
Project 88 Bang-Bang Bright
Now connect a 3-snap to make a connection between A & X. Keep
the photoresistor connected between points C & Z. Now depending
on how much light reaches the photoresistor, you will hear either
an ambulance or machine gun sound.
Project 89 Daylight Danger
Now remove the connection between A & X and then make a
connection between B & Y. The circuit works the same way but
now depending on how much light reaches the photoresistor you
will hear either a police siren or machine gun sound.
Project 90 Crooks & Cars
Project 86

14
Although this circuit seems simple,
inverters or NOT gates are very
important in digital logic circuits.
Same or “NOT”
Build the circuit shown. Notice that when the press switch (S2) is
pressed, the LED (D1) goes off. This is an example of an inverter
circuit, or NOT gate. Whenever the input is high (switch is on), the
output is low (LED is off) and whenever the input is low (switch is off)
the output is high (LED is on). Disassemble the circuit when nished to
avoid draining your batteries.
Two-way Light Switch
Build the circuit on the left. Note that two of the 2-snaps are left
unconnected on one end because they will be used as switches in this
project. If you connect the free ends of each of these 2-snaps both to
the “high bar” or positions B in the gure or both to the “low bar” or
positions A in the gure, the LED (D1) lights up. But if you connect the
free end of one of the 2-snaps to the “high bar” and the free end of the
other 2-snap to the “low bar”, then the LED does not light up.
Project 91
Project 92

15
This circuit is commonly called an OR gate.
OR gates are used in digital logic circuits to
perform logical additions. When one of the
inputs is high (one of the switches is on) the
output is high (LED on). The output will only
be low (LED off) if both inputs are low (both
switches are off).
This circuit is commonly called an AND gate. AND
gates are used in digital logic circuits to perform
logical multiplies. When one of the inputs is low (one
of the switches is off) the output is low (LED off). The
output will only be high (LED on) if both inputs are high
(both switches are on). Combinations of AND and OR
circuits are used to add and multiply numbers together
in modern computers. These circuits are made of tiny
transistors in massive integrated circuits.
This OR That
Build the circuit shown. Notice that if you turn on the slide switch (S1)
OR press the press switch (S2) the LED (D1) lights up. There is no
partially lit state here, the diode is either totally on or totally off. While this
may seem very simple and boring, it represents an important concept in
electronics. Two switches like this may be used to turn on a light in your
house, or they might be two sensors at a railroad crossing used to start
the ding-ding sound and lower the gate. You could also have more than
two switches and the circuit would function the same way.
This AND That
Build the circuit shown. Notice that if you turn on the slide switch (S1)
AND press the press switch (S2) the LED (D1) lights up. Once again,
there is no partially lit state here, the LED is either totally on or totally
off. Two switches like this may be used to turn on the same light in your
house, the room switch and the master switch in the electrical box. You
could also have more than two switches and the circuit would function
the same way.
Project 93
Project 94

16
Neither This NOR That
Build the circuit at left and test the combinations of the slide switch (S1)
and press switch (S2). If you compare it to the OR circuit in Project
93, you can see the LED (D1) lights in the opposite combinations of
that circuit. Hence, we refer to it as a NOR circuit (short for “NOT this
OR that”). Like the OR and AND, it is an important building block in
computers.
This circuit is commonly called a NAND gate.
NAND gates are used in digital logic circuits to
perform an inverted logical multiply. When one
of the inputs is low (one of the switches is off)
the output is high (LED on). The output will only
be low (LED off) if both inputs are high (both
switches are on).
NOT This AND That
Build the circuit at left and test the combinations of the slide switch (S1)
and press switch (S2). If you compare it to the AND circuit in Project
94, you can see the LED (D1) lights in the opposite combinations of
that circuit. Hence, we refer to it as a NAND circuit (short for “NOT this
AND that”). This circuit can also have more or less than two inputs,
though when it only has one input it is referred to as a NOT circuit.
Like the OR, AND, and NOR, NAND and NOT are important building
blocks in computers.
Project 95
Project 96
This circuit is commonly called a NOR gate. NOR
gates are used in digital logic circuits to perform
an inverted logical add. When one of the inputs
is high (one of the switches is on) the output is
low (LED off). The output will only be high (LED
on) if both inputs are low (both switches are off).

17
Power Pitch
In the circuit, the outputs from the alarm (U2) and music ICs are
connected together. Build the circuit shown and then place the alarm
IC (U2) directly over the music IC (U1), resting on three 1-snaps. Turn
on the slide switch (S1) and you will hear a siren and music together.
Push the press switch (S2) and the fan spins, while the sound may not
be as loud. The fan may rise into the air when you release the switch.
This circuit is similar to Project #47, but the fan will y a little higher
since the sound circuit no longer drives the lamp (L1) and therefore
uses less battery power.
Light Makes Light
Build the circuit to the left. Cover the photoresistor, turn the switch on, and
notice that the LED is on for several seconds and then goes off. Uncover
the photoresistor and place the unit near a light and the LED will light. Cover
the photoresistor (RP) again and the LED will turn off. The resistance of
the photoresistor decreases as the light increases activating the U1 IC that
varies the voltage to the LED making it light.
Use the preceding circuit. Connect the motor (M1) across points A1
and C1 on the base grid, and remove the photoresistor (RP). Turn the
switch on and the LED (D1) lights for several seconds then goes out.
Turn the shaft of the motor and the LED will light again. As the motor
turns, it produce a voltage. There is a magnet and a coil inside the
motor. When the axis turns the magnetic eld will change and generate
a small current through its terminals. This voltage then activates the
music IC.
Project 98 Go & Glow
Project 97
Project 99
WARNING: Moving parts. Do not touch the fan or
motor during operation. Do not lean over motor.

18
Project 101
Build the circuit shown
on the left. The circuit
uses the Alarm and
Space War ICs to ash
the LED (D1). Turn the
switch on and the LED
starts ashing.
Connecting the output of the Alarm
or Music ICs to multiple devices
(such as the LED, speaker and
lamp) enables these devices
operations to be synchronized.
Wet your ngers with some
water or saliva and touch them
across points A and B several
times to hear some space war
sounds. Push the press switch
(S2) to hear more sounds at
the same time.
This circuit uses your body to
conduct electricity, and turn on
the circuit.
Wetting your ngers improves
the connection between the
metal and your nger.
Two-Tone Twinkler
Turn the switch (S1) on and the lamp (L1) and LED (D1) start ashing.
You hear two different tones driving the LED and lamp. ICs can be
connected to control many different devices at the same time.
Project 100
Project 102
Touch & Go
Flashing Flare