Project 47 Copyright © 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.
Table of Contents Basic Troubleshooting Parts List How to Use Snap Circuits® About Your Snap Circuits® SOUND Parts Introduction to Electricity Sound in Our World 1 2, 3 4 5-7 8 9-14 WARNING: SHOCK HAZARD - Never connect Snap Circuits® to the electrical outlets in your home in any way! Basic Troubleshooting 1. Most circuit problems are due to incorrect assembly, always double-check that your circuit exactly matches the drawing for it. 2.
Parts List (Colors and styles may vary) Symbols and Numbers (page 1) Important: If any parts are missing or damaged, DO NOT RETURN TO RETAILER. Call toll-free (800) 533-2441 or e-mail us at: help@elenco.com. Customer Service • 150 Carpenter Ave. • Wheeling, IL 60090 U.S.A. Qty. ID r1 Name Symbol Part # Base Grid (11.0” x 7.
Parts List (Colors and styles may vary) Symbols and Numbers (page 2) Important: If any parts are missing or damaged, DO NOT RETURN TO RETAILER. Call toll-free (800) 533-2441 or e-mail us at: help@elenco.com. Customer Service • 150 Carpenter Ave. • Wheeling, IL 60090 U.S.A. Qty. ID Name r1 Q2 r1 Part # Qty. NPN Transistor 6SCQ2 r1 Tube for Sound Energy Demo Container 6SCSEDCT R1 100W Resistor 6SCR1 r1 Flexible Sheet for Sound Energy Demo Container (may include spare) 6SCSEDCF r1 R3 5.
How to Use Snap Circuits® Snap Circuits® uses building blocks with snaps to build the different electrical and electronic circuits in the projects. Each block has a function: there are switch blocks, light blocks, battery blocks, different length wire blocks, etc. These blocks are different colors and have numbers on them so that you can easily identify them. The blocks you will be using are shown as color symbols with level numbers next to them, allowing you to easily snap them together to form a circuit.
About Your Snap Circuits® SOUND Parts (Part designs are subject to change without notice). BASE GRID The base grid is a platform for mounting parts and wires. It functions like the printed circuit boards used in most electronic products, or like how the walls are used for mounting the electrical wiring in your home. BATTERY HOLDER RESISTORS The batteries (B1) produce an electrical voltage using a chemical reaction.
About Your Snap Circuits® SOUND Parts The photoresistor (RP) is a light-sensitive resistor, its value changes from nearly infinite in total darkness to about 1000W when a bright light shines on it. Photoresistor (RP) SPEAKER The speaker (SP) converts electricity into sound by making mechanical vibrations. These vibrations create variations in air pressure, which travel across the room. You “hear” sound when your ears feel these air pressure variations.
About Your Snap Circuits® SOUND Parts The echo IC (U28) contains resistors, capacitors, and integrated circuits that are needed to add echo effects to a sound. A schematic for it is available at www.snapcircuits.net/faq. OTHER PARTS The egg LED attachment can be used with the color LED (D8) to enhance the light effects. The stereo cable is used to connect the audio jack (JA) to your music device or external speaker.
Introduction to Electricity What is electricity? Nobody really knows. We only know how to produce it, understand its properties, and how to control it. Electricity is the movement of subatomic charged particles (called electrons) through a material due to electrical pressure across the material, such as from a battery. There are two ways of arranging parts in a circuit, in series or in parallel.
Sound in Our World Sound is a variation in air pressure created by a mechanical vibration. See projects 13 & 51 for a demonstration of this. These air pressure variations travel across the room like waves, so we call them sound waves. You “hear” sound when your ears feel these air pressure variations, and convert them to nerve pulses that your brain interprets. Eventually the energy of a sound wave is absorbed, and becomes heat.
Sound in Our World In stereo, sound is produced on several speakers (or earphones) with varying frequencies/loudness on each. This gives the impression that the sound is coming from different directions, and is more pleasing to listen to. Mono sound is the same on all speakers, and is easier to produce. Note that a “stereo speaker” can be several speakers (possibly of different sizes) in one package. Your Snap Circuits® speaker (SP2) is a mono speaker.
Sound in Our World Some of a sound wave’s energy can reflect off walls or objects and come back to you. Normally you don’t notice these reflections when you are speaking because not all of the energy is reflected, and the delay is so short that your ears can’t distinguish it from the original sound, but sometimes (such as in a very large open room) you can hear them these are echoes! You hear an echo when a lot of the energy of your voice is reflected back to you after a noticeable delay.
Sound in Our World Electronically we amplify sound by converting the sound waves into an electrical signal, amplify the electrical signal, and then convert that back to sound waves. Ultrasound waves are above 20 kHz, beyond the range of human hearing. Bats use ultrasound waves to effectively “see” in the dark. Ultrasound waves are also used in medical imaging, to create pictures of muscles and organs in the human body. Ultrasound waves are sometimes used in cleaning items like jewelry.
Sound in Our World unnerving and unpleasant. Most electronic speech processing systems being developed use some form of speech prediction filters. relationships between both of your ears. The same thing applies to stereo sound. You may have heard the term acoustics; this is the science of designing rooms for best sound effects. Take a piece of string or rope roughly 4 feet long and tie one end of it to a chair or other piece of furniture.
Sound in Our World On your U26 keyboard, the blue keys approximate the 5th overtone notes, and the green keys approximate the 6th overtone notes; actual frequency may vary from the musical scale. The tone of the green keys can be adjusted with the tune knob, allowing them to be in tune with the blue keys, or out of tune with them.
DO’s and DON’Ts of Building Circuits After building the circuits given in this booklet, you may wish to experiment on your own. Use the projects in this booklet as a guide, as many important design concepts are introduced throughout them. Every circuit will include a power source (the batteries), a resistance (which might be a resistor, capacitor, speaker, integrated circuit, etc.), and wiring paths between them and back.
Advanced Troubleshooting (Adult supervision recommended) ELENCO® is not responsible for parts damaged due to incorrect wiring. 3. Snap wires: Use this mini-circuit to test each of the snap wires, one at a time. The LED should light. If you suspect you have damaged parts, you can follow this procedure to systematically determine which ones need replacing: (Note: Some of these tests connect an LED directly across the batteries without another component to limit the current.
Advanced Troubleshooting (Adult supervision recommended) 9. Keyboard (U26): Build project 92, but omit the 0.1mF capacitor (C2) and the 5.1kW resistor (R3). You should hear a tone when you press any key. Turning the TUNE knob while pressing any green key should change the tone slightly. Now add R3 to the circuit, and you should hear a continuous tone. If any of this does not work then the keyboard is damaged. 10. 0.
Project Listings Project # Description Page # Project # Description Page # Project # Description Page # 1 Electronic Keyboard 20 32 Low Pitch Optical Keyboard Echo 33 63 Your Music without Echo 46 2 Aligning the Keyboard 20 33 Keyboard Echo with Stereo Effects 34 64 Low Power Your Music without Echo 46 3 Be a Musician 21 34 Optical Echo in Stereo 35 65 Adjustable Music without Echo 46 4 Be a Musician (II) 21 35 Color Short Light 35 66 L/R Music Amplifier 47 5 Opti
Project Listings Project # Description Page # Project # Description Page # Project # Description Page # 94 Oscillator (III) 55 126 Daylight Voice Echo 63 158 Continuity Tester 73 95 Oscillator (IV) 55 127 Dark Voice Echo 64 159 High Low Light 73 96 Oscillator (V) 55 128 Dark Echo Light 64 160 Flicker Clicker 74 97 Oscillator (VI) 55 129 Dark Echo Variants 64 161 Fast Flicker Clicker 74 98 Left Right Bright Light 55 130 Day Echo Light 65 162 Slow Flicker Cl
Project 1 Electronic Keyboard Snap Circuits® uses electronic blocks that snap onto a clear plastic grid to build different circuits. These blocks have different colors and numbers on them so that you can easily identify them. Placement Level Numbers (1-snap wire is placed under the speaker) Placement Level Numbers Project 2 Build the circuit shown on the left by placing all the parts with a black 1 next to them on the board first. Then, assemble parts marked with a 2.
Project 3 Be a Musician To play a song, just press the key corresponding with the letter shown. If there is a “–” after a letter, press the key longer than usual. Mary Had a Little Lamb E D C D E E E– D D D– Rain, rain, E G G– Ma-ry had a lit-tle lamb, ED C D EE E Ma-ry had a lit-tle lamb, Whose fleece was white as F F Lit-tle lamb, lit- tle lamb. E D D Row, Row, Row Your Boat C– C– C D E– E D E F E D Rain, Rain, Go Away G E GGE G G E A C––– snow.
Project 5 Optical Theremin Build the circuit as shown. Turn on both slide switches (S1), and move your hand over the photoresistor (RP). You can adjust the sound just by moving your hand around. See what range of sounds you can produce, then change the amount of light in the room, and see how sound the range of sounds has changed. There may not be any sound if there is too much or too little light on the photoresistor.
Project 7 Voice Changer Build the circuit shown on the left by placing all the parts with a black 1 next to them on the board first. Then, assemble parts marked with a 2. Then, assemble the part marked with a 3. Install two (2) “AA” batteries (not included) into each of the battery holders (B1) if you have not done so already. Be sure to install the microphone (X1) with its “+” side positioned as shown.
Project 10 Echo If the speaker is too close to the microphone, then the speaker’s sound will be picked up by the microphone and be echoed again and again and again, until you can’t hear anything else. The same thing can happen if the room is too noisy, or if you talk too loud. Build the circuit as shown, and place it in a quiet room. Connect the speaker (SP2) using the red & black jumper wires, and then hold it away from the microphone (X1). Turn on the slide switch (S1).
Project 13 Sound Energy Demonstration Assemble the Sound energy demonstration container (as per page 4, or shown on next page) if you have not done so already. Build the circuit as shown. Turn off the left slide switch (S1) and turn on the right slide switch. Lay the speaker (SP2) down on the unused 3-snap and 6-snap wires (to elevate it slightly off the table); be sure it is lying flat, and place the sound energy demonstration container over it. Pour some salt, glitter, small foam or candy balls of 0.
Part B: Optical Version Modify the circuit to be this one, which has the photoresistor (RP) instead of the adjustable resistor (RV). Turn on both slide switches and wave your hand over the photoresistor (RP), to change how much light shines into it. The sound changes as your hand adjusts the light. At some hand positions the salt/glitter/balls will vibrate and bounce or dance around in the container; find the hand position that gives the best effects.
Project 14 Keyboard in Stereo This project requires stereo headphones or a stereo speaker; neither is included with this set, but this set does include a stereo cable to facilitate connection to your stereo speaker. Build the circuit as shown. Connect your own headphones or stereo speaker to the audio jack (JA). Turn on the slide switch (S1). Press keys on the keyboard (U26) and listen to the sound on your headphones or stereo speaker.
Project 16 Light & Sound Build the circuit as shown; note that a 2-snap wire is placed directly under the speaker (SP2). Turn off the left slide switch (S1) and turn on the right slide switch. Press keys on the keyboard (U26) to make sound on the speaker (SP2) and light on the color LED (D8). If you hold a key down then the color LED will change colors. Now turn on the left slide switch.
Project 18 Let’s add motion to the preceding circuit. Modify the circuit to match this one. Turn off the left slide switch (S1) and turn on the right slide switch. Lay the speaker (SP2) down on unused 2-snap and 6-snap wires (to elevate it slightly off the table), be sure it is laying flat, and place the sound energy demonstration container over it (the container should have been assembled as per instructions on page 4). Pour some salt, glitter, small foam or candy balls of 0.
Project 20 Keyboard with Voice Changer Set the 500kW adjustable resistor (RV3) to mid-range, turn OFF the left slide switch (S1), and then turn on the right slide switch. Now turn on the left slide switch, you hear a beep signaling that you are recording. Press keys on the keyboard (U26) until you hear a beep (signaling that recording time is over), then turn off the left slide switch to exit recording mode.
Project 23 Voice Changer with Echo Build the circuit as shown; note that the microphone (X1) is covering a 2-snap wire, and that the 5.1kW resistor (R3) is a tight fit over the adjustable resistor (RV) but does fit. Set the 500kW adjustable resistor (RV3) to mid-range, set the adjustable resistor (RV) lever towards R3, turn OFF the left slide switch (S1), and then turn on the right slide switch. Now turn on the left slide switch, you hear a beep signaling that you are recording.
Project 25 Low Pitch Keyboard Build the circuit as shown. Turn off the left slide switch and turn on the right slide switch (S1), and press some of the green keys. Now turn on the left slide switch to add the 0.1mF capacitor (C2) to the circuit, and press some green keys again. The pitch (frequency) of the sound is lower now. The blue keys will not be affected. Adding the 0.1mF capacitor lowers the frequency (pitch) of the sound produced by the green keys, and makes them similar to the blue keys.
Project 29 Keyboard Echo Build the circuit as shown, and turn on the slide switch (S1). Press keys on the keyboard (U26) and hear the sound with echo on the speaker (SP2). RV adjusts the amount of echo, and RV3 adjusts the volume. Try this at different RV settings, because the effects are very interesting with both high and low echo amounts. Project 31 Optical Keyboard Echo Build the circuit as shown, and turn on both slide switches (S1).
Project 33 Keyboard Echo with Stereo Effects In this project you will listen to the keyboard sound both with and without echo, at the same time (in stereo). This project requires stereo headphones or a stereo speaker; neither is included with this set, but this set does include a stereo cable to help connect to your stereo speaker. Build the circuit as shown; note that the 5.1kW resistor (R3) is a tight fit over the adjustable resistor (RV) but does fit.
Project 34 Optical Echo in Stereo The project is similar to the preceding one, but adds optical control using the photoresistor (RP). Rebuild the preceding circuit to match this one. Follow the preceding circuit’s instructions, except also turn on the slide switch next to the photoresistor, and then wave your hand over the photoresistor to change the sound. The keyboard overhangs the base grid, so be sure the connections to it stay secure as you are pressing keys.
Project 36 Keyboard with Optical Theremin Build the circuit as shown and turn on the slide switch (S1). Press keys on the keyboard (U26), wave your hand over the photoresistor (RP) to adjust the amount of light shining on it, and listen to the sound. Push the press switch (S2) to change the pitch of the green keys. There may not be any sound if there is too much or too little light on the photoresistor. Project 38 Adjustable Dual Range Keyboard Build the circuit as shown and turn on the slide switch (S1).
Project 41 MP3 player Your Music with Echo Build the circuit, and turn on the slide switch (S1). Connect a music device (not included, but this set does include a cable to connect it) to the audio jack (JA) as shown, and start music on it. Set the volume control on your music device for a comfortable sound level, and adjust the amount of echo using the lever on the adjustable resistor (RV); move the lever up for more echo or down for less echo.
Project 43 Your Music Speed Changer Build the circuit as shown. Set the 500kW adjustable resistor (RV3) to mid-range, turn OFF the left slide switch (S1), and then turn on the right slide switch. Connect a music device (not included) to the audio jack (JA) as shown, and start music on it. Now turn on the left slide switch, you hear a beep signaling that recording has started. Wait until you hear a beep (signaling that recording time is over), then turn off the left slide switch to exit recording mode.
Project 47 Super Optical Keyboard Echo Build the circuit as shown. Turn off the left slide switch (S1), and turn on the right slide switch. Press some of the keyboard keys and listen to the echo. Move the lever on the adjustable resistor (RV) to change the amount of echo (up is maximum echo, down is no echo). Try this at different RV settings, because the effects are very interesting with both high and low echo amounts.
Project 50 Super Optical Keyboard Echo for Headphones Build the circuit as shown. This project requires stereo headphones or a stereo speaker (neither is included). Turn off the left slide switch (S1), and turn on the right slide switch. Press some of the keyboard keys and listen to the echo. Set the 500kW adjustable resistor (RV3) for most comfortable sound level (turn to the left for higher volume, most of RV3’s range will be very low volume).
Project 51 Sound is Air Pressure Sound is a variation in air pressure created by a mechanical vibration. For a demonstration of this, take a stereo speaker in your home (the larger the better), lay it on the floor, and start some music. 1. Place your hand on your stereo speaker and turn up the volume. Do you feel the speaker vibrate? 2. Now place a piece of paper on the speaker; if the sound is loud enough, you will see the paper vibrate. Project 52 3.
Project 53 Brightness Adjuster Build the circuit and turn on the slide switch (S1). Move the lever on the adjustable resistor (RV) to vary the brightness of the light from the color LED (D8). If desired, you may place the egg LED attachment on the LED. Resistors are used to control or limit the flow of electricity in a circuit. Higher resistor values reduce the flow of electricity in a circuit.
Project 56 Photo Brightness Adjuster Some materials, such as Cadmium Sulfide, change their resistance when light shines on them. Electronic parts made with these light-sensitive materials are called photoresistors. Their resistance decreases as the light becomes brighter. The resistance of your Snap Circuits® photoresistor changes from nearly infinite in total darkness to about 1kW when bright light shines directly on it. Note that a black plastic case partially shields the Cadmium Sulfide part.
Project 59 Cup & String Communication Sound, radio signals, and light all travel through air like waves travel through water. To help you understand how they are like waves, you can make a cup & string telephone. This common trick requires some household materials (not included with this kit): two large plastic or paper cups, some non-stretchable thread or kite string, and a sharp pencil. Adult supervision is recommended.
Project 60 MP3 player Project 62 Audio Amplifier Build the circuit, and turn on the slide switch (S1). Connect a music device (not included) to the audio jack (JA) as shown, and start music on it. Set the volume using the lever on the adjustable resistor (RV). This is a simple amplifier, so the sound may not be very loud. Project 61 Low Power Audio Amplifier Use the preceding circuit, but replace one of the battery holders (B1) with a 3-snap wire. The circuit works the same but is not as loud now.
Project 63 MP3 player Your Music without Echo Build the circuit, and turn on the slide switch (S1). Connect a music device (not included, but this set does include a cable to connect it) to the audio jack (JA) as shown, and start music on it. Set the volume control on your music device for a comfortable sound level. Here we are using the amplifier inside the echo IC (U28), without adding any echo effects to the music.
Project 66 L/R Music Amplifier Build the circuit, and turn on the slide switch (S1). Connect a music device (not included) to the audio jack (JA) as shown, and start music on it. Use the lever on the adjustable resistor (RV) to adjust the volume for the left and right outputs of your music device; both won’t be loud at the same time. MP3 player The left and right outputs of your music device are intended to control separate speakers, but are combined here because you only have one Snap Circuits® speaker.
Project 68 Microphone Resistance - LED The microphone changes resistance when exposed to changes in air pressure, such as from sound waves or blowing on it. Talking into the microphone or blowing on it will change the LED brightness, but probably not enough for you to notice the difference. Build the circuit, and turn on the slide switch (S1). The color LED (D8) is dimly lit, because the resistance of the microphone (X1) keeps the current low.
Project 70 Time Light Project 71 Time Light (II) Build the circuit, and turn on the slide switch (S1). Push the press switch (S2) and set the 500kW adjustable resistor (RV3) so the color LED (D8) just comes on, then release the press switch. The color LED will be bright for a while and slowly get dim and go out. Push the press switch again to reset the color LED’s timer. Use the preceding circuit, but replace the adjustable resistor (RV) with the 5.1kW resistor (R3).
Project 74 Day Light Build the circuit, and turn on the slide switch (S1). Set the lever on the adjustable resistor (RV) so the color LED (D8) just gets bright. Now when you block the light to the photoresistor (RP), the color LED will turn off. If the color LED cannot be turned on or off at any RV setting, then change your room lighting. Project 76 Dark Light Project 75 Lower Day Light This circuit is like the preceding one, but can be used in darker rooms.
Project 78 Listen to the Light Change The color LED actually contains separate red, green, and blue lights, with a microcircuit controlling them. Each time the LED changes colors, the voltage across it changes. Each time the voltage changes, you hear a “click” from the speaker. Project 79 Adjustable Listen to the Light Change Turn on the slide switch (S1). Set the lever on the adjustable resistor (RV) for different brightness levels on the color LED (D8).
Project 81 LED Keyboard Control Build the circuit, and turn on the slide switch (S1). You hear a sound pattern that is synchronized with the color LED (D8) flashing. You can press keys on the keyboard (U26) to change the sound. The color LED turns off briefly when it changes colors. Here the color LED controls the keyboard through the transistor (Q2), so when the color LED turns off, the keyboard sound is also turned off. This produces the sound effects you hear.
Project 85 Capacitor Keyboard Control Build the circuit, and turn both slide switches (S1). You hear a sound pattern that is synchronized with the color LED (D8) flashing. Move the lever on the adjustable resistor (RV) to change the sound produced. You can also press keys on the keyboard (U26) to change the sound. Adding the capacitor changes the range of tones produced by the keyboard.
Project 88 LED Voice Keyboard Echo Build the circuit as shown. Place the circuit in a quiet room. Connect the speaker (SP2) using the red & black jumper wires, then hold it away from the microphone. Turn on the slide switch (S1). Talk into the microphone or press keys on the keyboard (U26), and listen the echo on the speaker. Adjust the amount of echo using the lever on the adjustable resistor (RV); move the lever up for more echo or down for less echo.
Project 92 Oscillator Build the circuit, and turn the slide switch (S1). You hear a tone. You can also press keys on the keyboard (U26) to change the sound. This circuit is an oscillator, because it produces a repetitive electrical signal on its own. You hear it as sound waves from the speaker. The signal is produced by a circuit inside the keyboard module, but may be controlled using your Snap Circuits® resistors and capacitors, and the keys on the keyboard.
Project 99 Adjustable Oscillator Build the circuit, and turn the slide switch (S1). Turn the knob on the 500kW adjustable resistor (RV3) to see the range of sounds that can be produced; there will only be sound for a small part of RV3’s range. You can also press keys on the keyboard (U26) to change the sound. RV’s 500kW adjustment range is wide, and the oscillator circuit inside the keyboard (U26) won’t function over RV’s full range.
Project 104 Clicker Build the circuit, and turn the slide switch (S1). The color LED (D8) is flashing, and you hear a clicking sound. The color LED turns off briefly when it changes colors. What you hear in the speaker is the change in current as the LED turns on or off. Project 105 Clicker with Echo Modify the preceding circuit to be this one, which adds echo effects. Turn on the slide switch (S1) and push the press switch (S2) to see the color LED (D8) flashing and hear a clicking sound.
Project 106 3V Audio Amplifier Build the circuit, and turn on the slide switch (S1). Connect a music device (not included) to the audio jack (JA) as shown, and start music on it. Turn the knob on the 500kW adjustable resistor (RV3) to adjust the volume. The transistor (Q2) amplifies the current from your music device, to make the sound louder. The resistors (R1 & RV3) and capacitors (C5 & C7) condition the signal to minimize distortion.
Project 109 Color Sound Normally the color LED changes colors, but here it doesn’t, why? The U26 keyboard produces a changing voltage, intended to produce sound on the speaker. The color LED is designed for use with a stable voltage (like the batteries); when used with the changing voltage from the keyboard, it gets confused and blurs its pattern. Red is the easiest color for the color LED to produce, and blue is the hardest. So when the voltage to it is weak, the more difficult colors get dim first.
Project 113 White Light Build the circuit and turn the slide switch (S1). Press any key on the keyboard (U26), but just one key at a time. The color LED appears white, and isn’t changing colors like it normally does. If you look closely at the color LED you can see separate red, green, and blue lights on it, which combine to produce white. This is best seen in a dark room. You can also view it with the egg attachment on the color LED, which helps to blend the LED colors together.
Project 116 Super Voice Echo with Light Project 117 Press Echo Build the circuit as shown, and turn on the slide switch (S1). Talk into the microphone, and listen the echo on the speaker, and see it on the color LED (D8). Set the sound volume using the knob on the 500kW adjustable resistor (RV3). Adjust the amount of echo using the lever on the adjustable resistor (RV). Note: There will only be sound if RV3 is set towards the left (most of its range will have no sound).
Project 121 Echo Light Headphone Build the circuit as shown, and connect your own headphones (not included) to the audio jack (JA). Turn on the slide switch (S1). Talk into the microphone, and listen the echo on your headphones, and see it on the color LED (D8). Set the 500kW adjustable resistor (RV3) for most comfortable sound level (turn to the left for higher volume, most of RV3’s range will be very low volume); then adjust the amount of echo using the lever on the adjustable resistor (RV).
Project 125 Another Voice Echo Light Build the circuit as shown, and turn on the slide switch (S1). Talk into the microphone (X1) to light the color LED (D8) and hear your voice on the speaker (SP2). Adjust the amount of echo using the lever on the adjustable resistor (RV). Next, replace the microphone with the press switch (S2). Push the press switch to see light on the color LED, and hear a clicking sound from the speaker.
Project 127 Dark Voice Echo The photoresistor controls power to the echo IC (U28), and acts as an on/off switch. If the photoresistor is not dark enough, it may only partially turn on the echo IC, causing the echo IC to malfunction. Also, you must hold the speaker away from the microphone or the circuit may selfoscillate due to feedback. You also need a quiet room, with low background noise. Build the circuit as shown, and place it in a quiet room.
Project 130 Day Echo Light Build the circuit as shown, and place it where there is bright light shining into the photoresistor (RP). Turn on the slide switch (S1). If the color LED never turns off, then you need brighter light on the photoresistor. Talk into the microphone, and see the color LED (D8) flash. Now block the light to the photoresistor to turn off the circuit; slowly wave your hand over it to turn the echo on and off while talking.
Project 134 Tone Stoppers Build the circuit and turn the slide switch (S1). Press any key on the keyboard (U26). You hear a tone from the speaker (SP2), though it may not be very loud. Now push the press switch (S2) while pressing the same key. The sound is louder now, because the press switch bypassed the 0.1mF capacitor. Capacitors can store electricity in small amounts.
Project 138 Tone Stoppers (V) In project 137, there is only sound for a small part of RV3’s range, which can be difficult to tune. To help, modify the circuit to add the adjustable resistor (RV) in series with RV3, as shown. Slowly adjust RV and RV3 to vary the tone from lowest to highest possible, while pressing S2 on and off, to see how the capacitors (C7, or C2 or C5) change the sound. You can also replace RV3 with the photoresistor (RP).
Project 141 Day Keyboard Build the circuit (note that there is a 4-snap wire under Q2, partially hidden) and turn the slide switch (S1). Press keys on the keyboard (U26). This keyboard only works during the day, so you have to have light on the photoresistor or there won’t be any sound. If you cover the photoresistor or place the circuit in a dark room then it won’t work. If the light is dim then the sound may be abnormal.
Project 143 Color Keyboard Build the circuit and turn the slide switch (S1). Press and hold down any green key on the keyboard (U26), and see what happens. Project 144 Color Keyboard (II) Modify the preceding circuit by adding the adjustable resistor (RV) as shown here. Turn the slide switch (S1). Move the lever on the adjustable resistor around; best effects are when it is to the left. Press keys on the keyboard (U26) at the same time. You will see some cool effects.
Project 147 Color Keyboard (V) Turn on the slide switch (S1). Move the lever on the adjustable resistor (RV) around near the left (not the middle or right). Press any of the blue keys for more effects. Pressing the green keys may not do anything. Project 148 Color Keyboard (VI) Use the preceding circuit, but replace the 1mF capacitor (C7) with the 0.1mF capacitor (C2). The sound is a little different now, and the green keys can change it.
Project 151 Play Fast Build the circuit and turn the slide switch (S1). Push the press switch (S2) and play keys on the keyboard (U26). Play fast, because this keyboard will only work for a few seconds! Push S2 again to restart the keyboard and its timer. Project 152 Red First The voltage needed to turn on an LED depends on the light color. Red needs the least voltage, and blue needs the most.
Project 153 Adjustable Timer Tone Note that there is a 3-snap wire under Q2, partially hidden. Turn on both slide switches (S1) and push the press switch (S2). You hear a tone, which turns off after a while. Push S2 again to restart the keyboard and its timer. Use the adjustable resistor (RV) to set how long the timer keeps the sound on for, it can be set for a few seconds or very long. You can change the tone that plays by pressing keys on the keyboard (U26).
Project 157 Water Alarm Build the circuit, and initially leave the loose ends of the red & black jumper wires unconnected. Turn on the slide switch (S1); nothing happens. Now place the loose ends of the red & black jumper wires into a cup of water, without their snaps touching each other. You should hear a tone now, indicating that you have detected water! Don’t drink any water used here.
Project 160 Flicker Clicker Turn on the slide switch (S1). Move the lever on the adjustable resistor (RV) around to make the color LED (D8) flicker and make clicking or buzzing on the speaker (SP2). Press keys on the keyboard (U26) for more fun effects. Try pressing a blue key and a green key at the same time, while moving RV’s lever around. Project 162 Slow Flicker Clicker Use the preceding circuit, but replace the 1mF capacitor (C7) with the larger 470mF capacitor (C5).
Project 164 Little Battery Set the knob on the 500kW adjustable resistor (RV3) to the left. Place the color LED (D8) across the points marked B & C (“+” to B); the LED lights as the capacitor charges. Next, place the color LED across points A & B (“+” to A) instead; now the LED lights as the capacitor discharges. Move the color LED back to B & C and repeat. Use the knob on RV3 to vary the charge / discharge rate, but keep it close to the left (otherwise the LED would be too dim to see).
Project 167 Capacitors in Series Turn on the right slide switch (S1). Press any green key and compare the sound with the left slide switch on or off. With the left switch off, the 0.1mF and 1mF capacitors (C2 & C7) are connected in series. Turning on the left switch bypasses the 0.1mF capacitor. Notice that having the 0.1mF included has a big effect on the tone. Think of capacitors as storage tanks for electricity.
Project 171 Capacitors in Parallel Turn on the right slide switch (S1). Press any green key and compare the sound with the left slide switch on or off. Project 173 Capacitors in Parallel (III) Use the project 171 circuit, but replace the 0.1mF capacitor (C2) with the much larger 470mF capacitor (C5). Press any green key and compare the sound with the left slide switch on or off. (When the switch is on, hold down the key, because you will only hear a click every few seconds.
Project 175 Resistors in Series Inside the keyboard module (U26) is an oscillator circuit that produces separate tones for the blue and green keys. The frequency (pitch) of the tone is set using an internal resistor-capacitor network, with each key representing a different resistor value. The green keys can be adjusted using the tune knob. The tone of the green keys can also be changed using external resistors and capacitors, which is done in many of the projects.
Project 177 These five resistors are all connected in series, so the highest value, will have the most effect. Swapping the locations of any parts in the circuit (without changing the direction of their “+” side) will not change how the circuit works. Try it. Project 178 Lots of Resistors in Series Turn on the slide switch (S1). There are five resistors (R1, R3, RV, RV3, and RP), connected in series, that are controlling the current to the color LED (D8).
Project 179 Be a Loud Musician It’s Raining, It’s Pouring: A G E A G E GG E It’s A G E E rain-ing, it’s pour-ing, Rain-y days aren’t F F D D FF like to jump, we D D bor-ing. We G F E D like to splash, Let’s hope it rains till Jingle Bells EE E E E E EC mor-ning. E G C D E– Jin-gle bells, jin-gle bells, Jin-gle all the way, F F Some songs have been modified to C G F D C– make them easier one horse o-pen sleigh. to play on your keyboard.
Project 181 Morse Code Build the circuit and turn on the right switch (S1). Press one key in a series of long and short bursts with pauses in between, and use Morse Code to send secret messages to your friends. You can use the difference in pitch between keys to send messages to different people. For example, sending Morse Code with the blue C key can mean that the message is for one friend, using the green C key can mean it’s for someone else, the green B key can be someone else.
Project 182 Transistor Audio Amplifier Build the circuit with the speaker (SP2) connected using the red & black jumper wires. Set the adjustable resistor (RV) to mid-range, and turn on the slide switch (S1). Hold the speaker next to your ear and blow into the microphone (X1), or talk directly into it with your mouth close to it. This circuit amplifies your voice and plays it on the speaker.
Project 184 Build the circuit and turn on the switch (S1). Initially set the lever on the adjustable resistor (RV) to the left, then move it later to vary the range of sounds that can be produced. Make your parts using either the water puddles method (A), the drawn parts method (B), or the pencil parts method (C). Touch the metal in the jumper wires to your parts and listen to the sound.
Project 186 Test Your Hearing Project 187 See the Sound This project requires a smart phone with an internet connection, so you can download a free app. Find and download a “function generator” app that can generate sine and square signals. Visit the Snap Circuits® Sound product page at http://www.elenco.com/downloads/scs185/ to find a few suggestions. This project requires a smart phone with an internet connection, so you can download a free app.
Project 188 See the Spectrum This project requires a smart phone with an internet connection, so you can download a free app. Find and download a “spectrum analyzer” app that lets your smart phone view the frequency spectrum of a signal. Visit the Sound product page at Snap Circuits® http://www.elenco.com/downloads/scs185/ to find a few suggestions.
OTHER SNAP CIRCUITS® PRODUCTS! For a listing of local toy retailers who carry Snap Circuits® visit www.elenco.com or call us toll-free at 800-533-2441. For Snap Circuits® upgrade kits, accessories, additional parts, and more information about your parts visit www.snapcircuits.net. Snap Circuits® Jr.
SCS-185 SOUND Block Layout Important: If any parts are missing or damaged, DO NOT RETURN TO RETAILER. Call toll-free (800) 533-2441 or e-mail us at: help@elenco.com. Customer Service • 150 Carpenter Ave. Wheeling, IL 60090 U.S.A. Note: A complete parts list is on pages 2 and 3 in this manual. Base grid (11.0” x 7.
