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Snapino™ Access Kit Instruction Manual

Instructions and Labels for Blind or Visually Impaired Project Builders
Projects 1-20

American Printing House for the Blind

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UEB compliant

Ages 12-112

A Note About the FCC

The Federal Communications Commission (FCC) regulates use of the radio frequency spectrum in the United States to prevent products from interfering with each other.

Snapino™ has been tested and found to comply with the limits for a Class B digital device, pursuant to part 15 of the FCC Rules. These limits are designed to provide reasonable protection against harmful interference in a residential installation. Snapino generates, uses and can radiate radio frequency energy and, if not installed and used in accordance with the instructions, may cause harmful interference to radio communications. However, there is no guarantee that interference will not occur in a particular installation. If Snapino does cause harmful interference to radio or television reception, which can be determined by turning Snapino off and on, try to correct the interference by:

  1. Moving Snapino away from the receiver.
  2. Contacting Elenco® for help by calling (800) 533-2441, or e-mail us at .

FCC regulations for your Snapino require you to accept any interference from authorized sources and that you shut down if you are causing interference with other authorized products.

You should never modify the electrical circuit components inside your Snapino module (U31) as this may cause malfunctions or violate FCC regulations for this product.

Conforms to all applicable U.S. government requirements and CAN ICES-3 (B)/NMB-3 (B).

Warnings

Hazards

WARNING: This product should ONLY be powered using a USB cable, the 9V battery holder in the set, or an AC adapter with 9V output (not included)! It should NEVER be used with Snap Circuits® battery holders or other power sources!

WARNING: SHOCK HAZARD Never connect Snapino to the electrical outlets in your home in any way other than with an AC adapter with 9V output (not included)!

WARNING: CHOKING HAZARD Small parts. Not for children under 3 years.

Cautions

WARNING: Always check your wiring before turning on a circuit. Never leave a circuit unattended while the batteries are installed. Never connect additional batteries or any other power sources to your circuits. Discard any cracked or broken parts.

Adult Supervision: Because children’s abilities vary so much, even with age groups, adults should exercise discretion as to which experiments are suitable and safe (the instructions should enable supervising adults to establish the experiment’s suitability for the child). Make sure your child reads and follows all of the relevant instructions and safety procedures, and keeps them at hand for reference.

This product is intended for use by adults and children who have attained sufficient maturity to read and follow directions and warnings.

Never modify your parts, as doing so may disable important safety features in them, and could put your child at risk of injury.

Batteries

Parts List

Important: If any parts are missing or damaged, DO NOT RETURN TO RETAILER. Call toll-free (800) 533-2441 or email us at: help@elenco.com. Customer Service, 150 Carpenter Ave., Wheeling, IL, 60090, U.S.A.

You may order additional/replacement parts at our website: www.snapcircuits.net.

Qty. ID Name Part #
1 2 2-Snap Wire 6SC02
1 3 3-Snap Wire 6SC03
1 5 5-Snap Wire 6SC05
1 9V Battery Holder and Switch 6SCB9
1 Base Grid Mini (7.7” x 5.5”) 6SCBGM
1 D1 Red LED 6SCD1
1 D2 Green LED 6SCD2
1 D10 Red/yellow Bi-color LED 6SCD10
1 White Jumper Wire SCJ3F
1 Red Snap-to-pin Wire 6SCJ5RED
1 Q4 Phototransistor 6SCQ4
1 R4 Resistor 10kΩ 6SCR4
1 S2 Press Switch 6SCS2
1 U31 Snapino Module 6SCU31
1 USB Cable (A-male to B-male) 9TLSCUSBAB

About Your Snapino Parts

(Part designs are subject to change without notice.)

Note: There is additional Arduino information at www.arduino.cc, including a schematic for the Arduino UNO.

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 how the walls are used for mounting the electrical wiring in your home.

The Snap Circuits® Snapino base grid is approximately 7.5 x 5.5 inches. It has five rows and seven columns of pegs. Between the rows and columns of pegs are hexagon-shaped holes. The top left snap pin is labeled A1 in braille. The columns are numbered 1-7 from left to right, and the rows are labeled A-E from top to bottom. Because the board is small, and the pegs are easy to count, only the starting peg (A1) is labeled in braille.

Note: We recommend that you take a few minutes to practice the exercises below before you begin building projects. Knowing how to place parts in the right locations ensures that your projects work properly, and saves you from the frustration of misplaced parts.

Most of the projects require building in separate "layers." That is, snapping parts on top of other parts. Your skill in finding coordinates with confidence pays off in finding pegs that are already in use.

Practice Exercise 1

Name a coordinate pair (e.g., F4, A3, or C6) and then point to the peg at that location. Hold your finger on the peg while you double-check your answer. Repeat this numerous times using different coordinates all over the board.

Practice Exercise 2

Reverse the previous procedure by first pointing to a peg anywhere on the board and then naming its coordinates. Repeat this numerous times with different peg locations.

Repeat both exercises with different locations until you are confident and accurate with your answers.

Snap Wires and Jumper Wires

Wires transport electricity, just like pipes are used to transport water. The colorful plastic coating protects them and prevents electricity from getting in or out. The Snap and Jumper wires in this kit are called wires because they are used like flexible wires.

There are three blue snap wires, which are plastic wire connectors used to connect components and to transport electricity, but do not affect circuit performance. They come in different lengths that span two, three, and five snaps to allow orderly arrangement of connections on the base grid.

The white jumper wire with snaps on both ends makes flexible connections for times when using the snap wires would be difficult. If using snap jumper wires from other kits the color does not matter, but colors are used in electronics to visually distinguish different kinds of electrical signals for what each wire does. For example, black wire is usually used for the path to the negative battery terminal.

The red snap-to-pin wire allows for direct connection to the Arduino UNO circuit board.

Battery Holder

Batteries, like that in your 9V battery connector, produce an electrical voltage using a chemical reaction. This “voltage” can be thought of as electrical pressure pushing electricity through a circuit, just like a pump pushes water through pipes. This voltage is much lower and much safer than the voltage used in your house wiring. Using more batteries increases the "pressure" of the electricity pushed through the wire, which in turn, increases the flow of electricity. Snapino circuits can also be powered through the USB.

The Snapino 9V battery holder is a rectangle box. If you place the battery holder on the table with the switch up and the wire to the right, the On position is towards you. On the bottom of the battery holder, directly under the switch, is a small Phillips-head (+) screw that secures the battery cover.

To change the battery, keeping the wire to the right, remove the screw and slide the cover to the right. Press with your thumb on the battery and slide the battery to the left until it disconnects from the battery holder. Put in a new battery, replace the cover, and tighten the screw.

Switches

The press switch (S2) and the switch in the 9V battery holder connect (pressed or ON) or disconnect (not pressed or OFF) the wires in a circuit. When ON, they have no effect on circuit performance. Switches turn on electricity just like a faucet turns on water from a pipe.

LEDs

The red and green LEDs (D1, D2) are light emitting diodes and may be thought of as a special one-way light bulb. In the “forward” direction (indicated by the arrow in the symbol), electricity flows when the voltage exceeds a turn-on threshold (red and yellow ≈ 1.5V, green ≈ 2.0V, and blue ≈ 3.0V); brightness then increases. Too high of a current burns out an LED, so your Snap Circuits® LEDs have internal resistors to protect them. LEDs block electricity in the “reverse” direction. The braille label is placed on the positive side of the diode, which helps you align the diode in the circuit. Place the side with the label on the side of the circuit coming from the positive terminal of the power source. For a Snapino piece, that is the snap labeled with a plus sign.

The red/yellow LED (D10) is similar to the others but has red and yellow LEDs connected in opposite directions. This special LED is labeled with a 'Y' on the side that connects to positive to forward bios the Yellow light; and an'R' on the side that connects to the positive to forward bios the Red light.

Resistors

Resistors “resist” the flow of electricity, and are used to control or limit the current in a circuit. This set includes a 10kΩ resistor (R4) (“k” symbolizes 1,000, so R4 = 10,000Ω). Materials like metal have very low resistance (<1Ω), while materials like paper, plastic, and air have near infinite resistance. Increasing circuit resistance reduces the flow of electricity. There is only resistor in Snapino, and it has a braille label of R4.

Phototransistor

The phototransistor (Q4) is a transistor that uses light to control electric current. The phototransistor has a braille label of Q4.

Cable

The USB cable is used to program and communicate with the Snapino module (U31).

Snapino Module

The Snapino module (U31) is an Arduino UNO microcontroller mounted on a Snap Circuits® base. This is a mini computer you program to perform different tasks, including monitoring and making things happen.

The module is rectangle shaped, with a smaller plastic-covered raised rectangle (circuit board) on top. Place the module flat on the table with the USB and power ports away from you. The ports are located at one end of the circuit board. With the module oriented like this, there are seven snap connectors to the right and bottom of the circuit board that make a backward L shape. There are two vertical slots in the plastic cover on top of the circuit board. These are the Arduino UNO headers and where you connect the Pin side of the snap-to-pin wire.

Arduino Snap and Header Connections

Front three-snap connections (from left to right)

Right four-snap connections (from front to back)

The header connections are two vertical slots located in the plastic cover on top of the circuit board of the module. These slots contain small holes where you connect the pin side of the snap-to-pin wire. It is very difficult to feel the holes with your fingers, as they are recessed below the plastic cover. However, you may be able to run a fingernail or thumbnail over them to feel where they are located.

Note: If you cannot see the individual pin holes, you can count to the location using the pin on the wire.

Left-side slot header

With the module flat on the table and the ports side away from you, the Analog Section is the lower, left section of 6 pin holes. In order, from closest to furthest away, the sockets are: A5, A4, A3, A2, A1, and A0. There is a slight separation between the lower 6 header pin holes and the upper 8 pins.

The top section of 8 pin holes is mostly related to the power supply. From bottom to top, these sockets are: voltage in, ground pin, another ground pin, 5V pin, 3V pin, reset pin, I/O reference pin, and an unused pin (for future boards).

Right-side slot header

With the module flat on the table and the ports side away from you, the digital pins begin in lower, right header section of 8 pin holes. From closest to furthest away, these are: D0, D1, D2, D3, D4, D5, D6, and D7.

The digital pins continue in the top header section of 10 pin holes. From closest to furthest away, the sockets are: D8, D9, D10, D11, D12, D13, ground pin, analog ref pin, I2C SDA, and I2C SCL.

Note: Snapino does not have an on/off switch when powered using the USB cable. To turn it off, disconnect the USB cable from your computer.

Using the Snapino Module in Other Applications

Power source: Snapino should ONLY be powered using a USB cable, the 9V battery holder included in the set, or an AC adapter with 9V output (not included). Snapino should NEVER be used with Snap Circuits® battery holders from other sets or other power sources.

Analog inputs: (snap A0, or pins A0-A5 on the circuit board) These measure voltage within 10-bit accuracy (1024 levels). They also act as additional digital inputs/outputs when properly configured.

Digital inputs/outputs: (snaps D9-D11 or pins 0-13 on the circuit board) When configured as inputs, the voltages are considered high when above 80% of the power source voltage, and considered low when below 20% of the power source voltage. When configured as outputs, each can supply or receive up to 20 mA; enough to light an LED, but an interface transistor may be needed for controlling a motor or speaker. Some voltages (3, 5, 6, 9, 10, and 11) can be configured to simulate analog outputs using Pulse Width Modulation (PWM).

Other pins on the circuit board can be accessed using snap-to-pin wires; see the orientation description of the Arduino UNO.

How to Use Snapino

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, and so on. These blocks are different colors and are labelled so that you can easily identify them. Each step of the accessible instructions has the name of the block and the braille label if applicable, followed by a position on the board to place the block. If the piece cannot be uniquely distinguished by touch, a braille label has been added. If the part needs to be placed with the positive side facing the positive terminal, the braille label is on the positive side.

For Example:
If the green press switch is needed for the circuit, the following is the instruction to place it spanning from A1 to A3:

Press switch S2 A1 - A3

If you are to place one of the wire blocks, the instructions indicate how many snaps are on the wire block. In this kit there are only the 2, 3, and 5 connector wire blocks. The wire block can be located without a label by counting the number of snaps. The wire blocks are blue and do not have braille labels. The following is the instruction to place a 3 wire snap circuit piece spanning from A1 to A3:

3 wire connector A1 - A3

You need a power source to run your circuits. You can use the USB cable or 9V battery holder (9V battery not included).

A clear plastic base grid is included with this kit to help keep the circuit blocks properly spaced. There are evenly spaced posts that the different blocks snap into. The base has rows labeled A-E and columns labeled 1-7. The A1 position has a braille label as an easy starting point for counting.

Each circuit instruction has a place where you put the part and a description of the part to be added.

Some circuits use jumper wires to make unusual connections. Just clip them to the metal snaps or as indicated.

There is a snap-to-pin wire that allows you to make connections directly to the Arduino UNO circuit board on the Snapino module (U31).

Cautionary Note: While building the projects, be careful not to accidentally make a direct connection across the positive and negative terminal (a “short circuit”), as this may damage and/or quickly drain the batteries.

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 sub-atomic charged particles (called electrons) through a material due to electrical pressure across the material, such as from a battery.

Power sources, such as batteries, push electricity through a circuit, like a pump pushes water through pipes. Wires carry electricity, like pipes carry water. Devices like LEDs, motors, and speakers use the energy in electricity to do things. Switches and transistors control the flow of electricity like valves and faucets control water. Resistors limit the flow of electricity.

The electrical pressure exerted by a battery or other power source is called voltage and is measured in volts (V). Notice the “+” and “–” signs on the battery; these indicate which direction the battery “pumps” the electricity.

The electric current is a measure of how fast electricity is flowing in a wire, just as the water current describes how fast water is flowing in a pipe. It is expressed in amperes (A) or milliamps (mA, 1/1000 of an ampere).

The “*power*” of electricity is a measure of how fast energy is moving through a wire. It is a combination of the voltage and current (Power = Voltage x Current). It is expressed in watts (W).

The resistance of a component or circuit represents how much it resists the electrical pressure (voltage) and limits the flow of electric current. The relationship is Voltage = Current x Resistance. When the resistance increases, less current flows. Resistance is measured in ohms (Ω), or kilo ohms (kΩ, 1000 ohms).

Nearly all of the electricity used in our world is produced at enormous generators driven by steam or water pressure. Wires are used to efficiently transport this energy to homes and businesses where it is used. Motors convert the electricity back into mechanical form to drive machinery and appliances. The most important aspect of electricity in our society is that it allows energy to be easily transported over
distances.

Note that “distances” includes not just large distances but also tiny distances. Try to imagine a plumbing structure of the same complexity as the circuitry inside a portable radio - it would have to be large because we can’t make water pipes so small. Electricity allows complex designs to be made very small.

There are three ways of arranging parts in a circuit: in series, parallel, or a combination of the two. Here are examples:

Series Circuit

A Series circuit is one with all the loads in a row. There is only ONE path for the electricity to flow. If this circuit was a string of light bulbs and one blew out, the remaining bulbs would turn off. If your house was wired in series and your stove blew out, your lights would go out.

Try the following example to build an easy series circuit:

Example Project: Series Circuit

Parts Needed

First Layer
 
  1. Snapino module 5V on A3 and GND on C3
  2. 3-Snap wire A1 - C1

Second Layer

  1. Red LED D1 A1 - A3 with positive on A3
  2. Green LED D2 C1 - C3 with positive on C1

Try removing a light. If you remove either light, the path is broken and the other light goes out.

Parallel Circuit

A Parallel circuit is one that has two or more paths for the electricity to flow; the loads are parallel to each other. If the loads in this circuit were light bulbs and one blew out, there is still current flowing to the rest of the circuit, because there is still a direct path from the negative to positive terminals of the battery.

A Parallel circuit is one with several different paths for the electricity to travel. It's like a river that has been divided into smaller streams; however, all the streams come back together at the same point to form the river once again.

Example Project: Parallel Circuit

Parts Needed

First Layer

  1. Snapino module 5V on A6 and GND on C6
  2. 3-Snap wire A2 - A4
  3. 5-Snap wire C1 - C5

Second Layer

  1. 2-Snap wire C5 - C6
  2. Press switch S2 A4 - A6
  3. Red LED D1 A2 - C3 with positive on A2
  4. Green LED D2 A3 - C3 with positive on A3

Try removing one of the LEDs. The other one continues to work, because they both have a pathway to power.

Combination Series and Parallel Circuit

A Combination circuit is one that has a combination of series and parallel paths for the electricity to flow. Its properties are a combination of the two. In this example, the parallel section of the circuit is like a sub-circuit and actually is part of an over-all series circuit. The parallel part of the circuit is the two lights. If you pull either of the two lights in parallel, the rest of the circuit continues to work. If you pull the light that is not in parallel with the other two, it breaks the whole circuit, because it is in series with the two lights in parallel.

Example Project: Combination Series Parallel Circuit

Parts Needed

First Layer

  1. Snapino module 5V on A7 and GND on C7
  2. 3-Snap wire A3 - A5
  3. 5-Snap wire C1 - C5

Second Layer

  1. Red and Yellow LED D10 C5 C7 (orientation does not matter)
  2. Press switch S2 A5 - A7
  3. Red LED D1 A3 - C3 with positive on A3
  4. Green LED D2 A4 - C4 with positive on A4

In this circuit the red LED D1 and the green LED D2 are in parallel with each other, and the red and yellow LED D10 is in series with the rest of the circuit. If you remove either of the red or green LED's, the circuit continues to work. If you remove the red and yellow LED, the circuit stops working.

DOs and DON'Ts of Building Circuits

After building the circuits given in user guide, you may wish to experiment on your own. Use the projects as a guide, as many important design concepts are introduced throughout them. Every circuit includes a power source (the 9V battery holder or USB cable), a resistance (which might be a resistor, LED (which has an internal protection resistor), etc.), and wiring paths between them and back.

You must be careful not to create “short circuits” (very low-resistance paths across the power source, see examples below) as this damages components and/or quickly drains your batteries. ELENCO® is not responsible for parts damaged due to incorrect wiring.

You are encouraged to tell us about new programs and circuits you create. If they are unique, we will post them with your name and state on our website at: www.snapcircuits.net/learning_center/kids_creation. Send your suggestions to ELENCO: elenco@elenco.com.

ELENCO provides a circuit designer so that you can make your own Snap Circuits® drawings. This Microsoft® Word document can be downloaded from: www.snapcircuits.net/learning_center/kids_creation or through the www.snapcircuits.net website.

Some Important Guidelines

ALWAYS USE EYE PROTECTION WHEN EXPERIMENTING ON YOUR OWN.
ALWAYS include at least one component that limits the current through a circuit, such as a resistor, an LED (which has an internal protection resistor), etc.
ALWAYS use switches in conjunction with other components that limit the current through them. Failure to do so creates a short circuit and/or damages those parts.
ALWAYS disconnect your power source immediately and check your wiring if something appears to be getting hot.
ALWAYS check your wiring before turning on a circuit.
ALWAYS connect the Snapino module (U31) using configurations given in the projects, as per the About Your Parts section [link], or as per the Arduino website [link].
NEVER connect to an electrical outlet in your home in any way.
NEVER leave a circuit unattended when it is turned on.
NEVER connect battery holders from other Snap Circuits® sets to the Snapino (U31) module.

Warning about power sources: Snapino should ONLY be powered using a USB cable, the 9V battery holder included in the set, or an AC adapter with 9V output (not included). Snapino should NEVER be used with Snap Circuits battery holders from other sets or other power sources.

Examples of Short Circuits - NEVER DO THESE!!!

Placing a 3-snap wire directly across the 5V OUT and GND snaps is a SHORT CIRCUIT.

Placing any number of snap wire connectors or wires in a series without resistance from 5V OUT to GND snaps is a SHORT CIRCUIT.

It is important that when you press a switch you do not cause a series circuit with no resistance to be formed between 5V OUT to GND snaps, which would be a short dependent on pressing the switch.

Troubleshooting (Adult supervision recommended)

Elenco and APH are not responsible for parts damaged due to incorrect wiring.

Basic Troubleshooting

  1. Most circuit problems are due to incorrect assembly; always double check that your circuit exactly matches the instructions.
  2. Be sure that parts with braille markings are correctly placed with the braille connected to the wires that connect to the 5V out.
  3. Be sure that all connections are securely snapped.
  4. Try replacing the batteries.

Advanced Troubleshooting

If you suspect you have damaged parts, follow these procedures to systematically determine which parts need replacing:

Snapino module (U31 - partial test, see step 6 for full test), 9V battery holder, and USB cable:

  1. Install a 9V battery into the battery holder
  2. Turn on the battery holder switch.
  3. Plug the holder into the Snapino module. A green ON light and another light on the Snapino module should be on.
  4. Remove the 9V battery holder.
  5. Connect the USB cable. The same lights on the Snapino module should be on.

If the Snapino lights do not come on in either case, the Snapino is damaged. If they only come on for one power source, the other power source is damaged.

Red LED (D1), Green LED (D2), and Red/yellow LED (D10):

  1. Place the Red LED across the 5V OUT and GND snaps on the Snapino module (U31), with LED “+” to 5V OUT. The Red LED should light.
  2. Repeat for the Green LED.
  3. Repeat for the Red/yellow LED, but test it in both directions.

If some LEDs work but others do not, the ones that did not work are damaged. If no LEDs work, the Snapino module is damaged.

White jumper wire and Red snap-to-pin wire:

Use this mini circuit to test the White jumper wire; the LED should light.

  1. Replace the White jumper wire with the Red snap-to-pin wire
  2. Snap it on the LED.
  3. Touch the pin end to the GND snap on the Snapino module (U31) to test it.

Snap wires: Use this mini circuit to test each of the snap wires, one at a time. The LED should light.

Press switch (S2), 10kΩ resistor (R4), and phototransistor (Q4):

  1. Build Project #1 - Red Light
  2. Push the Press switch. If the Red LED (D1) doesn’t light, the Press switch is bad.
  3. Replace the Press switch with the 10kΩ resistor; the LED should be much dimmer now, but still lit.
  4. Replace the 10kΩ resistor with the phototransistor (“+” on right), and vary the amount of light shining on it; more light should make the LED brighter.
  5. To do a full test on the Snapino module (U31) do the previous steps first to test all other parts needed for Project 15. Then build and run Project 15.

Project Listings

Project 1 - Red Light
Project 2 - Lights
Project 3 - Blinking Light - Programming Snapino
Project 4 - Alternating Lights
Project 5 - Stoplight
Project 6 - Button
Project 7 - Bicolor Light
Project 8 - Night Light
Project 9 - Blink Rate
Project 10 - Copy Cat Light
Project 11 - Light Monitor
Project 12 - Distance Sensor
Project 13 - Photo Stop
Project 14 - Button Stoplight
Project 15 - Snapino Test
Project 16 - Varying LED Brightness
Project 17 - Light Controlled LED
Project 18 - LED Brightness Button
Project 19 - Sloppy Switches
Project 20 - Click Counter

Project 1 - Red Light

Parts Needed

Optional: USB cable to USB device may be used as alternate power source in place of 9V battery.

Accessibility Note: When placing LEDs, the braille label is on the positive side of the diode snap piece. (As found in step 5.)

First Layer

  1. Snapino module 5V on A3, GND on C3, and D11 on C6
  2. 3-snap wire A1 - C1

Second Layer

  1. Press Switch S2 A1 - A3
  2. Red LED D1 C1 - C3 with Positive on C1

A. After building the circuit, install a 9V battery into the 9V battery holder, plug it into the connector on the Snapino module (U31), and turn on the switch on the battery holder. A small green light (usually labeled “ON”) on the Snapino module should be on, indicating that it has power. Alternately you may power the circuit using the USB cable instead of the 9V battery.

Push the Press switch S2, and the red LED (D1) lights.

Educational Note: When you press the Press switch, electricity flows from the Snapino module, through the switch and back to the Snapino module through the red LED. If the switch is not pressed, the flow of electricity is blocked, and the red LED won’t light.

For this and the next few circuits, the Snapino module is used only to provide power to the rest of the circuit. Snapino is powered using a 9V battery or through the USB, and produces a 5V output to operate other Snap Circuits® components.

NOTE: This circuit (and many others in this book) have an LED being used without a resistor or other component to limit the electric current through it. Normally this could damage an LED, but your Snap Circuits LEDs include internal protection resistors and will not be damaged. Be careful if you later use other electrical sets with unprotected LEDs.

B. Use the preceding circuit but replace the 3-snap wire with the red/yellow LED (D10 labeled in braille with 'r' and 'y' in either orientation). The red LED is a little dimmer now.

Educational Note: The voltage from the Snapino module (U31) is now split between the two LEDs, making the red one dimmer.

C. Use the preceding circuit but replace the red/yellow LED (D10 labeled with 'r' and 'y' in braille) with the 10kΩ resistor (R4). The red LED (D1) is much dimmer now.

Educational Note: Resistors “resist” the flow of electricity, so the LED is much dimmer now.

D. Use the preceding circuit but replace the 10kΩ resistor R4 with the phototransistor (Q4, “+” towards S2). Vary the brightness of light on the phototransistor to change the red LED brightness.

Educational Note: The resistance of the phototransistor varies depending on how much light is shining on it.

E. Replace the red LED (D1) with the green LED (D2) in any of the preceding four circuits.

Educational Note: The green LED needs a little more voltage to turn on than the red LED, so it is a little dimmer.

Project 2 - Lights

Parts Needed

Optional: USB cable to USB device may be used as alternate power source in place of 9V battery.

First Layer

  1. Snapino module 5V on A6 and GND on C6
  2. 3-Snap wire A2 - A4
  3. 5-Snap wire C1 - C5

Second Layer

  1. Red LED D1 A2 - C2 with positive on A2
  2. Green LED D2 A3 - C3 with positive on A3
  3. Press switch S2 A4 - A6
  4. 2-Snap wire C5 - C6
  5. One end of the white snap-jumper cable C4

Third Layer

  1. One end of the white snap-jumper cable C5
  2. Red/yellow LED D10 (labeled 'y' and 'r' in braille) on C4 and A4

A. Build the circuit, turn on the switch in the 9V battery holder, and push the Press switch (S2). The red, green, and yellow LEDs (D1, D2, & D10) light.

Note: The white jumper wire is used only as a spacer (so both snaps on the yellow LED are on level 3); its right snap need not be connected.

Educational Note: LEDs are light emitting diodes, which convert electrical energy into light. The color of the light depends on the characteristics of the material used in them.

B. Use the preceding circuit but reverse the position of the Press switch (S2), 3-snap wire, 5-snap wire, and each of the LEDs (D1, D2, & D10), separately.

Educational Note: Reversing the switch and snap wires has no effect. LEDs only work in one direction, so the red & green LEDs do not work in reverse, but the yellow LED (D10) is a bi-color LED, with separate red &
yellow LEDs in opposite directions, as shown in its symbol.

C. Use the project 2A circuit, but replace the Press switch (S2) with the phototransistor (Q4, “+” on right). Vary the brightness of light shining on the phototransistor, and see how it changes the brightness of the LEDs.

Educational Note: The resistance of the phototransistor varies depending on how much light is shining on it, brighter light lowers its resistance. In this circuit the phototransistor restricts the flow of electricity to all three LEDs at once, so it takes very bright light to make all three LEDs light. Some LEDs need less electricity to turn on than others, so they may turn on sooner.

D. Use the project 2A circuit, but remove the Press switch (S2) and move one of the LEDs (D1, D2, or D10) to where the switch was (place the LED “+” on the right). The LEDs may be a little dimmer now.

Educational Note: All the electricity flows through the LED that replaced the switch, then divides between the remaining two LEDs. The LEDs are a little dimmer because the battery voltage is split between them now.

Introduction to Microcontrollers

The Snapino module (U31) is an Arduino UNO microcontroller mounted on a Snap Circuits base. Arduino is an electronics platform for prototyping with easy-to-use hardware and software. Usually Arduino is used with a prototyping breadboard, but combining it with Snap Circuits—which has electronic parts and modules mounted on snaps—makes an even better prototyping platform.

This set is only intended as an introduction to Arduino. Users who want to learn more about it should visit the Arduino website (www.arduino.cc) after finishing the projects in this set.

What Is a Microcontroller?

A microcontroller is a mini computer. It’s a miniaturized circuit that contains memory, logic, processing, and input/output circuitry. Microcontrollers are programmed with specific instructions to control many different devices. Once programmed, the microcontroller is built into a product to make the product more intelligent and easier to use.

A microcontroller receives input from sources (e.g., a switch, phototransistor, or computer keyboard), processes it, and makes decisions. Then it controls outputs (e.g., an LED, speaker, motor, or computer display) based on the decisions.

For example, a microwave oven uses a single microcontroller to process information from the keypad, display use information on a display, and control the turntable motor, light, bell, and cooking time.

One microcontroller can often replace a number of separate parts or even a number of complete electronic circuits. Microcontrollers are used in household appliances, alarm systems, medical equipment, vehicle
subsystems, musical instruments, and electronic instrumentation. Most cars contain many microcontrollers, using them for engine management, remote locking, and other functions.

Programs are stored in memory as a series of numbers. A program is executed by moving information (stored as numbers) between places, such as activity registers, input/output ports, and memory. Computers cannot do complex mathematics, but they can perform simple math very quickly, and programming tricks allow complex calculations to be performed as a series of simple ones.

Installing Software and Programming Cable

Install the Arduino software—called the Integrated Development Environment (IDE) from the Arduino website (www.arduino.cc/en/main/software). Choose the appropriate version for your computer’s operating system (most users pick “Windows installer” or “Mac OS X”), then follow the installation instructions there. Depending on your operating system, you may be asked to agree to a
license agreement, or to give permission to install drivers.

When the IDE installation is complete, build the circuit shown here (which includes the red snap-to-pin wire, which is plugged into slot 13 of the black connector on the circuit board on the Snapino module (U31)), and connect the USB cable to your computer. The green LED (marked ON) on the circuit board should be on, and other lights may be on if the board had previously been programmed. Your computer should automatically find the drivers it needs. Run the Arduino IDE.

Select the Arduino UNO board if it is not selected under tools/boards in the Arduino IDE.

Now select the port for communicating with Snapino. In the Tools menu in the Arduino IDE, select Port, then pick the one that shows an Arduino UNO (Windows users) or either of the following: /dev/tty/usbmodem or /dev/cu.usbmodem5dll (Mac users).

The Arduino IDE is a Java program. If you are using a screen reader it needs to be a screen reader that supports the Java Access Bridge. Follow the instructions for your screen reader to setup the Java Access Bridge.

Project 3 - Blinking Light - Programming Snapino

Parts Needed

First Layer

  1. Snapino module 5V on A1, GND on C1, and D11 on C4
  2. Snap-to-pin cable E1 - U31 Digital socket 13

Second Layer

  1. Green LED D2 C1 - E1 positive side on E1

This project explains the procedure for programming the Snapino module (U31). The microcontroller can be reprogrammed in ANY circuit that uses it, by attaching the programming cable to it. When you initiate a new program download, any program currently running in the microcontroller is interrupted. When a new program download is complete, the new program begins running.

The USB cable is needed to download new programs to the microcontroller and to allow some programs to transfer information to/from the computer’s display. The USB also provides power to your circuits, so the 9V battery connector is ignored while you are connected to a USB device. Once Snapino has been programmed, you may disconnect the USB cable and run the circuit using the 9V battery connector.

Go to the Snapino product page (www.snapcircuits.net/scsnapino) and download the Snapino program files from the website to your computer. In the File menu in the Arduino IDE, pick Open, then go to where you downloaded the Snapino program files and pick the Blinking_Light program or “sketch” (Arduino users refer to a program as a sketch). The sketch should appear in the IDE window.

Now, download the program into the Snapino module. Click on the Upload button in the IDE.

The blue status bar near the bottom should indicate that the upload is occurring and when it is done. Two LEDs should now be blinking—a small yellow LED on the UNO board (usually marked “L”) and the green LED (D2) in Snap Circuits.

You can now disconnect the USB cable and connect the 9V battery holder. Turn on the switch on the 9V battery holder, and the sketch begins running.

Note: Snapino does not have an On/Off switch when powered using the USB cable. To turn it OFF, disconnect the USB cable from your computer.

Troubleshooting: If there is a problem with the upload, the status bar is orange, indicating a problem. If you unplug the USB cable and it does not recognize the module when USB is connected again, you may need to reselect the port. In Tools, select Port and pick the one that shows an Arduino UNO (Windows users) or either of the following: /dev/tty/usbmodem or /dev/cu.usbmodem5dll (Mac users).

Educational Note: Any time a task needs to be performed over and over again, a microcontroller should be considered to help perform the task.

Learn About Programming

You can edit the sketch to change parameters or commands if desired. The editing procedure is similar to other word processors. You may also type in a completely new sketch.

To save sketches you have created or modified, go to Save As under the File menu.

Only valid sketches (without errors) may be downloaded, or a downloading error results. You can check for errors by clicking the Verify box. Verify also tells you how much memory the sketch uses.

Explanations for all Arduino commands, and some basic information about programming, can be found under the Help menu or on the Arduino website (www.arduino.cc).

Here is how the sketch works:

void: sets up a function
setup: a function that initializes variables, pin modes, etc.
pinMode(13, OUTPUT): configures digital pin 13 to act as an output
loop: a function for executing commands in a continuous loop
digitalWrite(13, HIGH): tells Snapino to put an electrical voltage at digital pin 13 (where the Snap Circuits® green LED (D2) is connected). This voltage lights the LED. A small yellow LED on the UNO circuit board also lights; this LED is permanently connected to digital pin 13.
delay(500): tells Snapino to pause for 500 milliseconds, or 0.5 second, before performing the next instruction
digitalWrite(13, LOW): tells Snapino to turn off or remove any voltage at digital pin 13. This turns off the green LED (and the yellow LED on the UNO board).

Comments: All information after // is Comments. Comments are a description of what the sketch is doing, to help you understand and remember it. Comments are automatically removed before the sketch is downloaded to Snapino.

You can change the blink rate by changing the delay value from 500 to something else. Try 200 (faster blinking) or 2000 (slower blinking). Change the value at both locations in the sketch, then upload the sketch into Snapino.

Project 4 - Alternating Lights

Parts Needed

Accessibility note The braille labels on light-emitting diodes D1 and D2, mentioned in steps 4 and 5, are located on the positive side of the part.

First Layer

  1. Snapino module 5V on A1, GND on C1, and D11 on C4
  2. 5-Snap wire E1 - E5

Second Layer

  1. 3-Snap wire C1 - E1
  2. Green LED D2 C2 - E2 with positive on C2
  3. Red LED D1 C3 - E3 with positive on C3

Build this circuit: Load the sketch Alternating_Lights into Snapino using the programming instructions in Project 3. Arduino controls the two Snap Circuits LEDs (red and green), and alternates turning them on and off.

Programming Note: This sketch uses the int command (int is short for integer) to assign a constant value that is used within the sketch. You can change the blink rate by editing the delay value, then reloading it into Snapino.

The microcontroller on the Arduino UNO board lets you control the LEDs in ways that would be difficult to do using switches or other devices.

Project 5 - Stoplight

Parts Needed

First Layer

  1. Snapino module 5V on A1, GND on C1 and D11 on C4
  2. 5-Snap wire E1 - E5

Second Layer

  1. 3 Snap wire C1 - E1
  2. Green LED D2 C2 - E2 with positive on C2
  3. Red/yellow LED D10 C3 - E3 with braille label 'r' on C3
  4. Red LED D1 C4 - E4 with positive on C4

Build this circuit: Load the sketch Stoplight into Snapino using the programming instructions in Project 3. Snapino controls the three Snap Circuits LEDs (green, yellow, and red), and turns them on and off like a stoplight. The yellow light is only on for half as long, just like a normal stoplight.

Programming Note: This sketch uses the int command (int is short for integer) to assign constant values for the delay and LED connection pins. Doing this makes them easy to change later, because you only need to change them in one place, instead of throughout the sketch. You can change the blink rate by editing the delay value, then reloading it into Snapino.

Project 6 - Button

Parts Needed

First Layer

  1. Snapino module 5V on A2, GND on C2, and D11 on C5
  2. 5-Snap wire E1 - E5
  3. Resistor R4 A1 - C1

Second Layer

  1. 2-Snap wire A1 - A2
  2. 3-Snap wire C2 - E2
  3. Red light C4 - E4 with positive c4 /li>
  4. Press switch C1 - E1
  5. One side of the white jumper cable C3

Third Layer

  1. One end of the white jumper cable C1

Build this circuit: Load the sketch Button into Snapino using the programming instructions in Project 3. The red LED (D1) should be on; push the Press switch (S2) to turn it off.

Swap the locations of the Press switch and 10kΩ resistor (R4). Now the red LED turns on when the press switch is pushed.

Programming Note: This sketch monitors the voltage between the 10kΩ resistor and the Press switch; normally the resistor pulls the voltage high, but pushing the switch pulls it low. Snapino monitors the voltage and
turns off the red LED when it receives a low signal from the button. If the button is released, the monitored voltage goes back to high, and Snapino turns on the red LED.

digitalRead(button): command that tells Snapino to read the voltage at the button (which had been assigned as digital pin 9), and assign it to a variable-button state.

Project 7 - Bicolor Light

Parts Needed

First Layer

  1. Snapino module 5V on A2, GND on C2, and D11 on C5
  2. 2-Snap wire E2 - E3

Second Layer

  1. Red/yellow LED D10 C3 - E3 (orientation does not matter)
  2. Snap wire C2 - E2

Build the circuit. Load the sketch Bicolor_Light into Snapino using the programming instructions in Project 3. The red/yellow bicolor LED (D10) alternates between red and yellow.

Programming Note: The red/yellow bicolor LED (D10) has red and yellow LEDs connected in opposite directions. The sketch instructions alternate between turning digital pins 9 and 10 HIGH or LOW, so that electricity flows out of one and into the other.

Try reducing the delay to 100 to make it change colors faster. Next, reduce the delay to 10 to make it change colors really fast - so fast that red and yellow blend into orange.

Project 8 - Night Light

Parts Needed

First Layer

  1. Snapino module 5V on A2, GND on C2, and D11 on C5
  2. Phototransistor Q4 A1 - C1
  3. 5-Snap wire on E1 - E5

Second Layer

  1. Resistor R4 C1 - E1
  2. Red LED D1 C3 - E3 with positive on C3
  3. One end of the white jumper cable B2
  4. Snap wire on A1 - A2
  5. 3-Snap wire on C2 - E2

Third Layer

  1. One end of the white jumper cable on C1

Build this circuit. Load the sketch Night_Light into Snapino using the programming instructions in Project 3. Cover the phototransistor (Q4) to turn on the red LED (D1).

Once programmed, you can use the 9V battery connector to power the circuit instead of the USB cable, then take the circuit with you into a dark room.

Programming Note: analogRead(0) - command that measures the voltage at analog pin A0 using a 10-bit analog-to-digital converter, and outputs a value from 0 to 1023 (representing a voltage of 0V to 5V).

You can adjust the sensitivity by changing 200 to be higher or lower.

Project 9 - Blink Rate

Build the circuit in Project 8, but load the sketch Blink_Rate into Snapino. The red LED (D1) is blinking; the darker the room, the faster it blinks. If the room is very dark then the red LED may appear to be on continuously.

Swap the locations of the 10kΩ (R4) resistor and phototransistor (Q4). Now brighter light makes the LED blink faster and darkness makes it slower.

Project 10 - Copy Cat Light

Build the circuit in Project 8, with the R4 and Q4 locations swapped (so Q4 connects to the 5-snap wire). Load the sketch Copy_Cat_Light into Snapino. Place the circuit in a bright room, so there is light on the phototransistor (Q4). Block the light to the phototransistor with your hand; when you uncover it, the red LED (D1) stays on for as long as the phototransistor was covered. Try this several times.

Programming Note: This program uses a counter to keep track of how long you cover the phototransistor. The longer you cover it, the higher the counter gets. Once the phototransistor is uncovered, the LED turns on, and the program starts subtracting from the counter. This can count backwards until the counter is equal to zero, where it would then turn the LED off.

Project 11 - Light Monitor

Parts Needed

First Layer

  1. Snapino module 5V on A2, GND on C2, and D11 on C5
  2. Phototransistor Q4 on A1 - C1
  3. 5-Snap wire on E1 - E5

Second Layer

  1. Resistor on C1 - E1
  2. One side of white jumper cable B2
  3. 2-Snap wire on A1 - A2
  4. 3-Snap wire on C2 - E2

Third Layer

  1. One side of white jumper cable C1

This project opens a window on your computer to display measured data in real time.

Build the circuit shown. Load the sketch Light_Monitor into Snapino using the programming instructions in Project 3. When the upload is finished, click on the Tools menu, then pick Serial Monitor from the list. A window opens on your computer screen, displaying the measured light value. Vary the amount of light shining on the phototransistor (Q4) and see how the number displayed changes.

Programming Note: The Serial commands open the window, then display some text with the light measurement.

Changing the amount of light shining on the phototransistor changes its resistance, and so changes the voltage measured at the A0 input. The analogRead command has 10-bit accuracy, so the measured number is from 0 (darkest) to 1023 (brightest).

The 10kΩ resistor (R4) allows the voltage at the A0 input to fall when it is dark and rise when there is light on the phototransistor. The voltage measured depends on the ratio of the phototransistor resistance to the 10kΩ resistor (R4). The measured value is about 512 when the phototransistor resistance equals R4. Replacing R4 with another resistor would shift the measured light value.

Project 12 - Distance Sensor

Parts Needed

First Layer

  1. Snapino module 5V on A2, GND on C2, and D11 on C5
  2. Resistor R4 A1 - C1
  3. 5-Snap wire E1 - E5

Second Layer

  1. Phototransistor C1 - E1
  2. Green LED C3 E3 - E3 with positive C3
  3. Red/yellow LED D10 C4 - E4 with 'y' C4
  4. Red LED C5 E5 with positive C5
  5. 2-Snap wire A1 - A2
  6. 3-Snap wire C2 - E2
  7. One end of the white jumper cable B2

Third Layer

  1. One end of the white jumper cable on C1

This sketch changes which LED is ON depending on the amount of light the phototransistor is getting. Build the circuit and load the sketch Distance_Sensor into Snapino using the programming instructions in Project 3.

Vary the amount of light shining on the phototransistor (Q4) - if the light is bright, the green LED (D2) is ON; if there is less light, the yellow LED (D10) is ON; and if there is low light or no light, the red LED (D1) is ON. This can be used to determine the distance something is above it, since the object slowly blocks out more light the closer it gets to the phototransistor.

Once programmed, you can use the 9V battery connector to power the circuit instead of the USB cable, then walk around with it.

Programming Note: This sketch works by measuring how much light the phototransistor is getting, and assigning that value to a variable, in this case the variable is “Val”. The Arduino then uses this value to
determine which light to turn on. If the variable is above a certain value, the Arduino switches the LED from green to yellow, and if the value still gets too high, the Arduino switches the yellow LED to the red LED.

You can adjust the sensitivity by changing values 750 and 150 to be higher or lower.

Project 13 - Photo Stop

Build circuit in Project 12, but load the sketch Photo_Stop into Snapino. The LEDs change colors in a stoplight pattern, with the rate of change controlled by the phototransistor (Q4). Vary the amount of light shining on the phototransistor; the brighter the light, the faster the LEDs change.

Programming Note: This sketch reads the value from the phototransistor, and uses that value to change the time delay, causing the stoplight to switch the LEDs faster or slower.

Project 14 - Button Stoplight

Parts Needed

First Layer

  1. Snapino module 5V on A2, GND on C2, and D11 on C5
  2. Resistor R4 A1 - C1
  3. 5-Snap wire E1 - E5

Second Layer

  1. Press Switch S2 C1 - E1
  2. Green LED D2 C3 - E3 with positive on C3
  3. Red/yellow LED D10 C4 - E4 with 'y' on C4
  4. Red LED D1 on C5 - E5 with positive on C5
  5. 2-Snap wire A1 - A2
  6. 3-Snap wire on C2 - E2
  7. One end of the white jumper cable B2

Third Layer

  1. One end of the white jumper cable C1

Build this circuit. Load the sketch Button_Stoplight into Snapino using the programming instructions in Project 3. The red LED (D1) should be on; push the Press switch (S2) to change which LED is on, the order is red-yellow-green like a stoplight.

Programming Note: This sketch uses a counter to switch between different LEDs. When the button is pressed, it increases the counter by 1. Each LED is activated when the counter reaches a certain number. When the counter reaches 4, it is reset to back to 1.

Project 15 - Snapino Test

Parts Needed

First Layer

  1. Snapino module 5V on A3, GND on C3, and D11 on C6
  2. 2-Snap wire on E3 - E4
  3. 5-Snap wire on A1 - E1
  4. One end of the white jumper cable E6

Second Layer

  1. Red LED D1 E1 - E3
  2. Green LED D2 A1 - A3
  3. 3-Snap wire C1 and C3
  4. One end of the white jumper cable E4

This circuit tests the snap connections on the Snapino module (U31), and is referenced by the Advanced Troubleshooting procedure.

Build the circuit as shown, leaving one end of the white jumper wire unconnected for now. Load the sketch Snapino_Test into Snapino using the programming instructions in Project 3.

The green LED (D2) should be on. Connect the loose end of the white jumper wire to each of the unused snaps on the Snapino module (U31), one at a time; the red LED (D1) should be blinking each time. Remove the USB cable, then connect the 9V battery holder and turn on its switch; the circuit should work the same as with the USB cable.

Programming Note: This sketch sets each connection on Snapino to be an output, then toggles each on and off.

Project 16 - Varying LED Brightness

Parts Needed

First Layer

  1. Snapino module 5V on A1, GND on C1, and D11 on 4
  2. 5-Snap wire on E1 - E5

Second Layer

  1. Red LED D1 C4 - E4
  2. Green LED D2 C3 - E3
  3. Red/yellow LED D10 C2 - E2
  4. 3 Snap wire on C1 - E1

Build the circuit and load the sketch Varying_LED_Brightness into Snapino using the programming instructions in Project 3. The three LEDs (D1, D2, & D10) continuously vary in brightness.

Programming Note: This sketch uses a counter to increase the brightness of the LEDs. Once the LED nears full brightness, the counter decreases to make the LEDs dimmer.

Some of the digital pins (including D9, D10, and D11, which are connect-to snaps and used here) may be controlled using the analogWrite() command. The analogWrite() command simulates an analog voltage using pulse width modulation, which varies the duration of a digital pulse. Here the LEDs are made brighter by increasing the duration of the pulse (making the LEDs on for a longer amount of time), or made dimmer by decreasing the duration of the pulse.

The value for analogWrite() can be from 0 (LED off) to 255 (LED always on). This sketch uses a maximum value of 30 for analogWrite(), because the LED brightness would change very slowly for higher values. Try increasing this value from 30 to 255, upload the sketch to Snapino, and see how it affects the LED brightness. You can also adjust the delay value (currently 30) to make the LED brightness change faster or slower.

Why do analogWrite() values of 30 or more make the LEDs appear at full brightness? Because the light is changing faster than your eyes can adjust, and your eyes continue seeing what they have just seen. This is often called “persistence of vision”. This concept is used in movie theaters.

Project 17 - Light Controlled LED

Parts Needed

First Layer

  1. Snapino module 5V on A2, GND on C2, and D11 on C5
  2. Resistor R4 A1 - C1
  3. 5-Snap wire E1 - E5

Second Layer

  1. Phototransistor C1 - E1
  2. Red LED D1 C3 - E3 with positive on C3
  3. 2-Snap wire A1 - A2
  4. 3-Snap wire C2 - E2
  5. One end of the white jumper cable B2

Third Layer

  1. One end of the white jumper cable C1

Build the circuit and load the sketch Light_Controlled_LED into Snapino using the programming instructions in Project 3. Vary the brightness of light on the phototransistor (Q4) to change the brightness of the red LED (D1). The red LED gets brighter as the phototransistor gets darker. The circuit acts as a night light, making the red LED brighter as the room gets darker.

Programming Note: The light on the phototransistor is measured with the analogRead() command, then 1/16 of that value is used for the red LED brightness with the analogWrite() command. The value is divided by 16
because analogRead() returns a number between 0 and 1023, while the analogWrite() value must be between 0 and 255, and because the red LED appears to be near full brightness for values >30.

Project 18 - LED Brightness Button

Parts Needed

First Layer

  1. Snapino module 5V on A2, GND on C2, and D11 on C5
  2. Resistor R4 A1 - C1
  3. 5-Snap wire E1 - E5

Second Layer

  1. Press switch S2 C1 - E1
  2. Red LED D1 C3 - E3 with positive on C3
  3. 2-Snap wire A1 - A2
  4. 3-Snap wire C2 - E2
  5. One end of the white jumper cable C1

Third Layer

  1. One end of the white jumper cable on C3

Build the circuit and load the sketch LED_Brightness_Button into Snapino using the programming instructions in Project 3. Push the Press switch (S2) repeatedly; the red LED (D1) gets brighter each time. After the red LED reaches full brightness, it resets and starts over.

Programming Note: The red LED brightness is set using the analogWrite() command, which uses values from 0 to 255; but incremental increases are much more noticeable between low numbers than between high numbers. Because of this, this sketch uses an array to set the red LED brightness in multiples of 2, then resets back to minimum.

Project 19 - Sloppy Switches

Build the circuit in Project 18 and load the sketch Sloppy Switches into Snapino using the programming instructions in Project 3. Slowly push the Press switch (S2) many times, watching the red LED (D1) as you do. Usually the LED turns on or off when you push the switch, but sometimes it stays the same. Do you know why the LED sometimes stays the same?

Programming Note: When you push the switch, its contacts may bounce, sometimes making equipment monitoring the switch think it was pressed more than once. This effect is called “switch bounce.” To prevent this, a small delay is normally added to ensure the switch contacts have settled before the sketch checks the switch again.

In this sketch the delay(10); command has // in front of it, making it a comment that is ignored by the sketch. Remove the //, upload the revised sketch, and see if the red LED always changes when you push the switch.

Project 20 - Click Counter

Build the circuit in Project 18 but upload the sketch Click_Counter into Snapino. When the upload is finished, click on the Tools menu, then pick Serial Monitor from the list. A window opens on your computer screen. Push the Press switch (S2) as many times as you like; the program displays the current count on your computer screen. The red LED D1 is not used, and may be removed.

Programming Note: Remove the delay(10); command from the sketch (or add // in front to make it a comment that is ignored), upload the revised sketch, and watch the display as you are pushing the Press switch. Notice that sometimes the display shows you pushed the switch several times when you only push it once.

To Go Further

Snap Circuits is an ideal environment for working with Arduino due to the ease of building circuits with it. The modules available in your Snapino set comprise only a small fraction of those available. For a full listing, go to www.snapcircuits.net. Additional Snapino sketches for use with other Snap Circuits sets are available at the Snapino product page (www.snapcircuits.net/scsnapino).

Only 9 of the Arduino UNO connection points are accessible by snaps on the Snapino module and some of those (A1 & A2) are not used in any Snapino projects; they are available for future experimenting on your own. The UNO connection points that are not accessible by snaps may be accessed using snap-to-pin wires, which may be purchased from Elenco in 10-packs as SCJW-10.

This set is only intended as an introduction to Arduino. Users who want to learn more about it should visit the Arduino website (www.arduino.cc) after finishing the projects in this set. Explanations for all Arduino commands, and some basic information about programming, can be found under the Help menu in the Arduino software IDE, or on the Arduino website (www.arduino.cc).

WARNING: This product should ONLY be powered using a USB cable, the 9V battery holder included in the set, or an AC adapter with 9V output (not included). It should NEVER be used with Snap Circuits battery holders
or other power sources!*

Some graphical programming languages have been developed to make Arduino programming easier by picking command blocks from a list instead of typing in a program; these may be helpful to new Arduino users. One is Ardublock; see www.ardublock.com to learn more about it.

Trademarks Attributions and Credits

Arduino™ is the trademark of Arduino, LLC and is used here in full compliance with Arduino, LLC's open source policy.

The Snapino™ PC Board Assembly is fully Arduino™ compatible.

This manual for Snapino Access Kit was prepared by APH using the instructions taken from the manual of Snapino™ Model 6SCU31 (Copyright © 2017 by ELENCO® Electronics, Inc. U.S. Patents: 7,144,255; 7,273,377; & patents pending). Used with permission.

Notice: Accessibility of APH Websites