Prototyping with Microcontrollers and Sensors
Objectives
The objective of this lab is to utilize the basics of electronics, the Arduino board, and the Arduino IDE (Integrated Development Environment). The Arduino IDE will be used to program the Arduino board. These skills will be used for several hands-on tasks including programming the Arduino to control an LED with a button, take readings with a temperature sensor, and design a basic prototype for a product.
Overview
Electricity
To put simply, electricity is the movement of electrons. Electrons flow through a conductive wire when there is a difference in charge between two points in the wire. This flow of electrons is called electrical current and it is measured in Amperes (A). Due to convention, electrical current flows opposite of the electrons. The difference in charge is called electrical voltage and it is measured in Volts (V). Another way to think about electrical voltage is to picture it as “electrical pressure,” analogous to water pressure. If there is a tank full of water (electrons) and a hole is poked in it, water will flow (electrical current flowing), due to the water pressure (electrical voltage) inside the tank. Finally, there are certain materials that resist that flow of electrons. This property is called electrical resistance and it is measured in Ohms (Ω). Resistors are electronic devices that are specifically designed to resist the flow of electrical current.
There exists a mathematical relationship between current, voltage and resistance which is characterized by Ohm’s Law. This relationship is detailed below, where V is the voltage across a resistor, I is the current flowing through a resistor and R is the resistance of the resistor.
Electronic Components
There are several basic electronic components used to build simple circuits. Some of these components are polarized which means the way they are connected matters! Another way of thinking about it is that some components are symmetrical while others are not.
DC (Direct Current) Voltage Sources
DC Voltage Sources are used to power circuits because they have a voltage difference across their terminals. DC Power Sources are usually batteries (AA, AAA, etc). Arduino boards can be powered by a battery, a USB cable, or an AC adapter. When the Arduino is powered, it can be used as a 5V DC voltage source. They ARE polarized.
Resistors
Resistors are components that reduce the amount of current flowing through a circuit. Resistors convert the excess current to thermal energy. Resistors can be used to control the voltages and currents of circuits. Resistors are color coded with what resistance they are. They are NOT polarized.
Capacitors
Capacitors are components that can store energy in an electrical field and then dissipate it at a later time. Capacitance is a measure of how much charge a capacitor can store and it is measured in Farads (F). Capacitors resist voltage changes by supplying or drawing current. They are SOMETIMES polarized.
Inductors
Inductors are components that can store energy in a magnetic field and then dissipate it at a later time. Inductance is a measure of how much energy an inductor can store and it is measured in Henrys (H). Inductors resist current changes by dropping or increasing the voltage across itself. They are NOT polarized.
Push-buttons and Switches
Push-buttons and switches are mechanical devices that interrupt or divert current running through them. Basic push-buttons and are polarized while basic switches are not.
