Download pdf - 16Hertz Electronics Starter Kit Guide

16HERTZ GUIDE

ELECTRONICS STARTER KIT

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16Hertz Electronics Project Starter Kit With over 30 items and 200 components, the 16Hertz Electronics Starter Kit is the kit you need to get started with electronics projects. It has all the components you need for beginner to moderately advanced projects. With just the components in the kit, you can build hundreds of projects, learn the basics of electronics and circuit building. It is also a great addition to any micro-controller like the Arduino or the Raspberry Pi. The following guide will introduce you to the key components in the kit and help you get started building electronic devices. There are detailed diagrams and explanations for all the circuits described thorough out this guide.

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3 16 hertz Inventory of Parts Quantity Item 1 400 point breadboard 1 Jumper Wires, assorted lengths 1 AA battery holder 1 DC Motor (3V) 1 RGB LED (common cathode) 1 Thermistor 1 10k Potentiometer 2 Photoresistors 5 PN2222 Transistors 5 BC547 Transistors 5 1N4001 Diodes 1 RGB LED 2 Red LED (5mm) 2 Blue LED (5mm) 2 Green LED (5mm) 2 Yellow LED (5mm) 2 White LED (5mm) 1 Thermister 1 Piezo Buzzer 5 22pF Ceramic Capacitor 5 0.1 F Ceramic Capacitor 2 50V 100F Electrolytic Capacitor 2 50V 10F Electrolytic Capacitor 5 Push-button switches 1 9V Battery Connector 5 10, 100, 200, 330, 1k, 10k, 100k, 1m Resistors


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LED (Light Emitting Diode)

An LED is a semiconductor device that emits light. An LED has 2 leads, an anode (+) and a cathode (-). When a voltage difference is maintained across the two leads, a current begins to flow and depending on the configuration of the LED, it begins to emit light. The larger the current, the more intense the light it emits. Be careful not to send more current that the LED is rated for. Typically 5mm LEDs, like the ones in this kit are rated for around 25 mA of current.

This is the schematic symbol for an LED. The side with the arrows is the (-) side and the other is (+)

Ensure that the polarity of the LED leads match the polarity of your power source. If these leads are mixed up, your LED wont light up. It is a diode after all.

RESISTOR A resistor is a passive electrical component that acts to reduce the current flow while lowering the voltage across a circuit. The current flow through a resistor, or any component for that matter, is given by Ohms law (I=V/R)

Resistors are some of the most common elements in all circuits. In your kit you have resistors in 10 different values.

Description & Applications of Key Components


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Remember, to create values of resistance you can always connect resistors in series, one after another. For instance, if you need 530 of resistance, you can combine a 200 resistor and a 330 resistor.

The color bands on the resistor arent just there to make it look pretty, the resistance value and the tolerance of the resistor are encoded in them.

Each color of each band represents a different value. You can read the resistance value of a resistor shown to the right the following way:

First band Red 2 Second band Black 0 Third band Blue 1M Fourth band Gold 5% tolerance

Value of the resistor 20M +/- 5%

A useful mnemonic to remember the corresponding color for the number is:

Better Be Right Or Your Great Big Venture Goes West

The schematic symbol for a resistor is a line that resembles a triangular wave.

Remember, resistors dont have a polarity, so it doesnt matter which way you connect them to your circuit.


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400 POINT BREADBOARD

The breadboard, sometimes referred to as a solderless breadboard, is an essential tool for quick and easy electronics prototyping. It is equally used by those learning about electronics and circuitry, and the more advanced circuit builders.

The breadboard eliminates the need for soldering components together every time you want to build a circuit by allowing for temporary and easily changeable connections.

Each point on a breadboard is connected by a rail to its neighboring points, either horizontally or vertically, depending on where they are on the board. When a component is pushed into a point, it locks into place.

On the 400 point breadboard, points along the two vertical columns labeled by a + and a on either side are connected by a rail i.e. if a component is inserted into one of the points on this column, it is then connected via the rail to every other point in the vertical column.

Much the same way as the columns, points along each of the horizontal rows in the center of the board (denoted by numbers) are connected by a rail. Mind the there is a gap in the middle; the rails dont extend past it.

LED connected to breadboard

The rail inside a breadboard


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Using the Breadboard

CIRCUIT 1: Let There Be Light!

This circuit should enable you to turn your LED on. LEDs are usually rated for a certain current. Sending anymore current through the LED might cause it to blow.

Given a set voltage (4.8 V in our case) you can control the amount of current by changing the resistance in the circuit.

The relationship between current (I), voltage (V) & resistance (R) is given by Ohms law, I=V/R

Adding a 330 ohm resistor to our circuit means that the current in our circuit will be about 15 mA, and our LED can handle that.


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You can vary the brightness of the LED by increasing the resistance in the circuit. Now that you know how to get one LED to turn on, lets try getting a whole lot of them on! There are many different ways to connect components in a circuit. Lets explore a few of them and note their differences. The two of the simplest and most frequently occurring ways are connecting components in series or in parallel.

CIRCUIT 2: Series Circuit

Youve just built a series circuit. Components connected in series are all connected in a single path.


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CURRENT

Since there is one closed circuit, the same current flows through all the components. All 3 LEDs should light up, but notice the difference between the brightness between the LEDs in this circuit and the LED you lit up in Circuit 1.

Since the same current is flowing throughout the entire circuit, the brightness of all the LEDs should be the same. However, the current flowing

through the circuit is lower than what it was in Circuit 1. Ohms law (I=V/R) tells us that since the resistance in this circuit is larger than the resistance in Circuit 1, the current that flows must be lower. Since the overall current is lower, the brightness of each LED is also lower.

VOLTAGE

The voltage varies across each element. The voltage drop across each component can be calculated by Ohms law (V=IR).

CIRCUIT 3: Parallel Circuit

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A parallel circuit is another way to build a circuit. In a parallel circuit, there is more than one way to form a closed loop, for instance, the battery R1 & LED1 form a closed circuit on their own. This configuration leads to the voltage across the parallel circuit being the same, while the resistance in each of the individual closed circuits determines the current flow through each component.

PROS AND CONS

In a series circuit, every device must function for the circuit to be complete. One component malfunctioning in a series circuit breaks the circuit. However, in parallel circuits, there are many independent circuits, so all but one could be burned out, and the last one would still function.

RGB LED

In your kit, you shouldve gotten an RGB LED. The RGB LED is essentially 3 LEDs in one. It is a blue LED, green LED and a blue LED in one package. With the RGB LED you can create almost any color by varying the intensity of each each of the primary colors. Remember, you can vary the intensity of an LED by limiting the current that is sent to it.

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RGB LEDs come in two common flavors, common cathode and common anode. Cathodes are normally (-) and anodes are (+).

The RGB LED in the kit is a common cathode LED. This means that each of the 3 LEDs that make up the RGB LED have a common cathode i.e. you can ground the long lead (the cathode) and a positive voltage to each of the other 3 leads.

CIRCUIT 4: The Colors of the Rainbow

If you connect all the 3 colors with the same resistance, the same amount of current will

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flow through each of them and each color will glow with about the same intensity. We all know what happens when you combine the three primary colors, red, green and blue you get white!

So the RGB led in this circuit, with the same resistors connected to each color will glow white.

TO TRY

Try sending a different amount of current to each lead by changing the resistors around to see what other colors you can create.

QUESTION

Is this a series circuit or a parallel circuit?

POTENTIOMETER

A potentiometer or pot, is a variable resistor. Your kit comes with a rotary potentiometer with a range of about 10k.

As you turn the knob of the potentiometer, a sliding wiper inside moves along a track. This mechanism allows for varying resistances that depend on where the wiper is along the track at any given time.

Instead of changing resistors each time we want a new resistance in the circuit, we can use a potentiometer. Lets try using a potentiometer to control the intensity of one of the

colors in the RGB LED to see what colors we can create.

Potentiometers are used often in many devices from volume controls to scroll wheels on mice

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CIRCUIT 5: A Pot at the End of the Rainbow

Lets go one step beyond Circuit 4 where we left having to change resistors every time we wanted to control the intensity of a color.

This circuit will allow you to control the amount of current going into one of the leads of the RGB LED by changing the resistance in that circuit by turning the knob.

TO TRY

Try connecting the potentiometer to different leads of the RGB LED to see all the different colors you can make by turning the knob.

TROUBLESHOOTING

Make sure to connect the middle lead of the potentiometer to the desired circuit to control. The other two leads go the (+) and (-) terminals of the battery pack.

PHOTORESISTOR

Photoresistors, sometimes called photocells or light dependent resistors (LDR), are variable resistors that change their resistance based on how much light is incident upon it.

The resistance of a photoresistor decreases as the intensity of the incident light increases. In other

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words, the brighter the light, the lower the resistance and vice-versa.

Photoresistors are very versatile and easy to use. They are ideal for projects needing light sensitivity and dependency.

It is good practice to incorporate the photoresistor in a voltage divider circuit when using it.

CIRCUIT 6: Voltage Divider

A voltage divider circuit is one you will see a lot as you delve deeper into electronics. Lets say that we have a 9V signal that we want lowered to a 5V signal for simple and rudimentary purposes, where we dont mind energy loss and have a low current draw situation, voltage dividers are perfect.

Voltage divider circuits can spit out any fraction of the input voltage that you desire, as long as you have the components with the needed resistance values.

To calculate the needed resistance values, after applying Ohms law, you get the expression

You can see from this expression that when R1 decreases, Vout increases and when R2 increases, Vout also increases.

Voltage dividers might seem like a cure for everything, but be careful all that energy from reducing 9V to 5V has to go somewhere, this turns into heat. If you application is stepping down a large voltage or is drawing a considerable amount of current you will end up destroy resistors.

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CIRCUIT 7: Night-Light #1

This is our first attempt at a night-light. Try turning the lights on and off, or covering the photoresistor with your hand. What do you see?

After learning about the photoresistor as a resistor that changes its resistance depending on the light in the room, one might think that connecting it to an LED (Circuit 1) would suffice to create a night-light.

What do you think the issue is?

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PROBLEMS WITH DESIGN

First of all, we know that the resistance of the photoresister goes down as the incident light gets brighter. This translates to the LED glowing brighter. Therefore, its really a night-light in reverse.

Secondly, the resistance range of the photoresistor in our kit is about 10k and at this much resistance, our power supply wont supply enough current for our LED to glow very brightly.

POSSIBLE FIXES

We will be able to remedy the first problem of the inverted response to light intensity by the photoresister by making it R1 in a voltage divider circuit. Recall that in a voltage divider circuit, as the resistance of R1 decreases, the voltage that comes out increases. Therefore, we can get the desired effect of the LED getting dimmer as the room is brighter and vice-versa.

For the second problem, this can be remedied by changing the value of R2 in the voltage divider circuit such that the right voltage is given out of Vout.

CIRCUIT 8: Night-Light #2

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R1 330 ohm | R2 1k ohm

TO DO

Experiment with different values for R2 and see how this affects the circuit.

SWITCH

CIRCUIT 9: Breaking the Circuit

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Switches are a key part of any circuit. They allow for control by enabling you to break a circuit when you dont want any current flowing.

TRANSISTORS

Transistors are semiconductor devices. They are the sole reason why most of the modern electronics devices that we use today are possible. Their invention in 1947 lead to the modern electronics revolution of microchips and other semiconductor devices.

Transistors are essentially variable resistors. They vary their resistance based on another electric signal applied to its base (one of the three leads). In other words, a voltage or current applied t o the base affects the current that flows through the other two pins (emitter and the collector) of the transistor.

There are many kinds of transistors, but in your kit you will find NPN transistors (in later kits we include PNP transistors as well). In an NPN transistor you have to apply a positive voltage to the base to have current flowing from the collector to the emitter. On a PNP transistor a negative voltage has to be

Transistor 1 NPN

Transistor 2 PNP

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applied to the base to have current flow through the other two leads.

CIRCUIT 10: Touch Switch

Hold onto probe one with your left hand and probe 1 with your right, and see what happens to the LED.

Our bodies have a tremendous amount of resistance. When dry, our bodies have over 100k of resistance. So, one would think the amount of current that can flow thorough our bodies when connected to a 9V battery for would be too miniscule to do anything significant, but using a transistor, we can have that tiny bit of current to control the amount of current that flows through the collector and the emitter of the transistor.

The LED in this circuit is connected in an independent circuit (parallel) with the battery and the emitter and collector of the transistor. The small current that flows through the second independent (parallel) circuit which connects the battery with the base of the transistor and our body, causes enough current to flow through the LED circuit which lights it up.

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CIRCUIT 11: Night Light #3

This night light design builds on the previous two that we tried. It works out the kinks and should work best of all three.

THERMISTOR

The thermistor is a variable resistor like the photoresistor and the potentiometer, but unlike those two, it changes its resistance based on the temperature around it. The thermistor in our kit has a resistance range of about 10k ohm.

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CIRCUIT 12: Hot Light

A circuit similar to Circuit 8 or Circuit 11 can be made with the thermistor replacing the photoresistor. This circuit would essentially turn the light on and off based on the temperature around the thermistor.

PIEZO BUZZER

The word piezo comes from the phenomenon of piezoelectricity, electricity generated from the pressure inside of solid materials.

Piezo buzzers are set up so that when a voltage is applied to its leads it gives off a particular tone. Varying voltages give off varying tones. Though you would be able to connect it with a battery pack and various resistors to see all the different types of tones you can make, it is most effective connecting it to a microcontroller like the Arduino UNO, or the 16Hz UNO (an Arduino compatible microcontroller)

CIRCUIT 12: BUZZ AWAY

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To learn more about Arduinos and how to program them, please consult our Arduino Starter Guide.

The above circuit will get allow us to program the Arduino UNO to send different PWM (average voltage) signals to the buzzer. This will allow us to play any tone we want with the click of a few buttons instead of switching around resistors every time we want a different tone.

The following code will have the buzzer cycle through 10 tones. You can change

Arduino code:

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DC MOTOR (3V)

DC (direct current) motors are the simplest of electric motors. Though there are various kinds of DC motors (brushed, brushless, stepper, servo etc.) usually when a component is simply referred to as a DC motor it tends to imply a brushed DC motor.

DC motors are simple two-lead, electrically controlled devices that come with a rotary shaft on which wheels, gears, propellers, etc., can be mounted. DC motors can generate a considerable amount of revolutions per minute (rpms) for their size and can be made to rotate clockwise or counterclockwise by reversing the polarity applied to the leads. At low speeds, dc motors provide little torque and minimal position control, making them not ideal for

precision, position-control applications.

To really understand how motors work and how to use them effectively, we need to explore the intimate relationship electricity and magnetism share in nature. For starters, theyre essentially one and the same thing. What might appear to one observer as an electrical interaction between charged particles will appear to another observer in another inertial reference frame as a magnetic one. In other words, changing magnetic fields produce currents and currents produce magnetic fields.

In essence, motors have coils of wires surrounded by permanent magnets. When a current is sent through the coils, a magnetic field is produced. This magnetic field interacts with the magnetic field from the permanent magnets and causes the motor shaft to spin around. If the current is flipped around, the polarity of the magnetic field induced is also flipped around, causing the motor to spin the other way around.

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Each motor is build to spin at a certain rate (rpm) for a given voltage. If for the motor is caused to spin slower than it is rated for, due to a load, for example, then, the slower it spins the more current it draws. If there is a voltage supplied to the motor and the load on it is such that the motor does not spin, then the motor is drawing a tremendous amount of current as the resistance in the circuit is very little.

To remedy this, circuits with motors have whats called a motor driver and motors are either geared up or down depending on the typical load on them to prevent this stall from happening. Motor drivers are circuits that allow for both current limiting and allow us to reverse the direction of rotation by reversing the current (this part of the motor driver is called an H-Bridge).

The easiest way to fully control your motor is with a microcontroller like the Arduino or the 16Hertz Arduino compatible microcontroller and an H-Bridge. Microcontrollers allow us to send different signals to a transistor, which in turn controls the amount of current sent to the motor.

CIRCUIT 13: Motorin

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We can control the speed of the motor by changing the signal that goes into the base of the transistor. Recall that transistors are like variable resistors that change the resistance in the circuit that passes through the collector and the emitter. The motor is connected in the circuit that passes through the collector and emitter of the transistor. As the signal applied to the base of the transistor is changed by the microcontroller (16Hertz Arduino UNO compatible board), the transistor changed the amount of current that is supplied to the motor.

Okay, so you might ask, why not control the motor directly with signals from the digital PWM pin on the microcontroller, the same signals that are being sent to the transistor?

Well, there are a few reasons. Firstly, motors can very easily draw lots of current and microcontrollers like Arduino UNO cant supply more than 200mA reliably. To be absolutely safe and ensure reliability, we should really use a battery pack to power the motor instead of drawing current from the Arduino. Secondly, we can supply a smooth varying signal to the motor from the transistor that we cannot from the Arduino digital pins.

Arduino Code:

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H-Bridge

The H-Bridge is a circuit that can drive a DC motor in both directions. Recall that simply flipping the direction of the current does the same to the direction of motor. You can try this out yourself by connecting the motor to the battery pack and then trying it again with the polarities reversed.

The H-Bridge circuit enables us to do this without having to manually switch the polarities of the motor every time we want to change its direction.

The H-Bridge consists of four transistors, which essentially function like switches that complete the circuit when applied in pairs. When one pair is chosen the current flows in one direction and when the other is chosen the direction of the current is reversed.

NOTE: both connections should not be chosen at the same time, as this will cause a short circuit by connecting the + & - terminals of the battery together without much resistance in the circuit leading to a very high current draw.

You might ask, why not just use physical switches instead of transistors. Well, would you want to sit there flipping switches in pairs every time you want your motor to move forward or backwards. I think not.

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