Creation Crate classroom: lesson 1
Congratulations, you have taken the first step to learning how to create electrical circuits and control them using an Arduino Microcontroller. Creation Crate projects have been designed and tested by our developers and provide teachers with hands-on learning activities for students which reinforce core competencies and help them acquire a basic understanding of computer programming and hardware construction. These activities can be used as a starting point for younger students, or as supplemental material to existing lesson plans. Each kit contains all the components needed to build the electronic circuitry (hardware) and the basic code for students to input into the Arduino programming platform. Students will need access to a computer with Internet capabilities to download the Arduino software.
Each lesson can be used as a stand-alone activity, or as a complete unit providing exciting challenges for students to build a knowledge base of computer coding, and apply understanding of the construction and programming process to additional learning opportunities. Creation Crate activities are suited for both independent learning and collaborative groups depending upon your classroom configuration or student needs.
Arduino is a microcontroller that allows a person to connect input and output devices to the board and write programs that can make the output device(s) perform certain tasks or functions based on the input(s). Anyone - children, hobbyists, artists, programmers - can start tinkering just following the step by step instructions of a kit, like Creation Crate, or sharing ideas online with other members of the Arduino community.
Students will learn how a basic circuit works.
In this lesson students will learn the following:
- How to be safe around low-voltage electrical currents.
- The names, definitions, symbols, and usage of basic electrical components.
- How to power an electrical circuit.
- How to use a breadboard for prototyping circuits.
- How to build a basic electrical circuit.
A basic circuit consists of a power source and a load. The load is something that is utilizing the power, like a light bulb or a motor. Before creating a circuit, it is a good idea to draw it first. This is called a circuit diagram or electronic schematic. The circuit diagram uses symbols to represent the different electrical components. Let’s light up an LED.
In the example above we have a 9V power source that is providing a Direct Current (DC) to a Light Emitting Diode (LED). This is a closed circuit, meaning that there is nothing interrupting it along the way and there is full continuity.
Note that the triangle of the LED symbol is pointing in the direction of the current flow. Many electrical components are designed to only handle current flowing in one direction. Sometimes, if the polarity is reversed, the component will just not work and other times it will damage or destroy it. The positive side of the LED is called the Anode and the negative side is called the Cathode.
Also, when creating a circuit, it is important to understand the power needs of the load. Providing too much current may destroy the component; not enough current and it will not work properly. In this case, our LED cannot handle 9 Volts and will burn out instantly when the circuit is complete. One way to control the current traveling through the circuit is to use a resistor, which does exactly as the name implies and resists the flow of electricity. Let’s add one to our circuit.
You’ll notice that the resistor is on the negative side of the current flow in this diagram. The resistor can be placed on either side and will perform the same function. Furthermore, unlike the LED, the resistors we are using are axial-lead resistors which are non-bias, meaning it does not matter which direction you orient the leads to the flow of electricity.
Since we may not want the LED light to remain on all of the time, for the last component of our simple circuit we are going to add a switch. The switch is also non-bias and can be placed on either side of the current flow. It’s job is just to break the continuity of the circuit so the current cannot flow through it.
This completes our simple circuit and provides you with a starting point from which to build your Creation Crate projects. The projects will range in complexity. As you receive new projects throughout the year, you will be introduced to new components and concepts and build on this basic knowledge.
Alternating Current (AC) – An electric current that reverses direction in a circuit at regular intervals. This type of current is used to deliver electricity over long distances because it is more efficient and loses less energy as heat. The outlets in your home deliver AC power.
Direct Current (DC) – Electric current flowing in one direction only. This type of current is produced by sources such as batteries, solar cells, and dynamos.
Power (Electrical Power) – The rate, per unit time, at which electrical energy is transferred by an electric circuit. Power is measured in Watts. A Watt is a unit of power which equals one Joule per second and is represented by the letter W.
(Power) = (Voltage) x (Current)
P = V x I
Current (Electric Current) – The amount of electric charge flowing past a specified circuit point per unit time. Current is measured in Amperes which is represented by the letter I.
Voltage – The force, or pressure, of electricity. Also known as potential. Voltage is measured in Volts and represented by the letter V.
Load (Electrical Load) – An electrical component or portion of a circuit that consumes electric power. Examples of an electrical loads in your house would be the lights, television, washing machine, etc.
Resistance – A measurement of the difficulty encountered by a power source in forcing electric current through an electrical circuit, and hence the amount of power dissipated in the circuit. Resistance is measured in Ohms (Ω) and represented by the letter R.
Ohms Law – The equation used to calculate voltage, current, resistance or power. The law states that the direct current flowing in a conductor is directly proportional to the potential difference between its ends.
(Power) = (Current) x (Resistance)
V = I x R
Circuit – A configuration of electrically or electro magnetically connected components or devices.
Polarity (Electrical polarity) – The direction of current flow in an electrical circuit. Current flows from the positive pole to the negative pole.
Schematic – A procedural diagram of an electronic circuit or project.
Conductor – Conductors are materials that readily conduct electric current through electrical conduction. Wires made from copper, or other metals, are used to conduct electricity.
Insulator – A material that does not easily transmit energy, such as electric current. Different types of plastic are usually used to coat wires in order to prevent electricity from flowing in unintended directions.
Continuity – Occurs when the flow of current in a circuit is uninterrupted. The level of continuity is determined by the amount of resistance in the circuit. For example, when the light switch is in the OFF position, the circuit is broken and there is no continuity (infinite resistance). On the other hand, when it is in the ON position the current can flow and there is continuity (no resistance).
Multimeter – An instrument that measures electrical quantities such as voltage, resistance and amperage.
Breadboard (aka: prototyping board) – A thin plastic board full of holes used to hold components that are wired together. It is commonly used for prototyping and experimenting with circuit designs.
Jumper Wire – An electrical wire with a connector or pin at each, which is normally used to interconnect the components of a breadboard or other prototype or test circuit, internally or with other equipment or components, without soldering.
Stranded Wire – A group of wires (or combinations of groups of wires) usually twisted together wrapped under insulation.
Solid Core Wire – A single strand of wire under an insulated coating. These are generally stiffer than stranded wire and are used in jumper wires.
Diode – A two-terminal electronic component that conducts electricity primarily in one direction.
LED (Light Emitting Diode) – A diode that emits light when activated. When a suitable voltage is applied to the leads, electrons are able to recombine with electron holes within the device, releasing energy in the form of photons. This effect is called electroluminescence.
Switch – Device that is used to turn a circuit ON or OFF (complete or interrupt).
Momentary Switch – A switch that is only active when pressure is applied to it and then returns to its original state as soon as the pressure is released.
Capacitor – A device used in electrical circuits. The capacitor stores an electrical charge for a short period of time, and then returns it to the circuit. They are similar to a battery, but usually don’t store the charge for long periods of time.
Resistor – A component that resists an electric current by producing a voltage drop between its terminals in accordance with Ohm's law.
Variable Resistors (aka: potentiometer) – A potentiometer is a three-terminal resistor with a sliding or rotating contact that forms an adjustable voltage divider. Potentiometers are often used as volume controls on audio equipment or dimmer switches for lights.
LDR or Light Dependent Resistor (aka: Photoresistor) – A light-controlled variable resistor. The resistance of a photoresistor decreases with increasing incident light intensity; in other words, it exhibits photoconductivity.
Pulse – A short duration of current flow which rapidly alternates between HIGH and LOW.
Pulse Width Modulation – A method to control the speed of a motor by turning voltage on and off in rapid pulses. The longer the intervals, the faster the speed of the motor.
Accelerometer – Devices designed to detect and respond to changes in acceleration.