Sensors, Actuators and controllers

Coffee Maker: An Open-Loop Control Systems

Coffee Maker: An Open-Loop Control Systems For example, consider a coffee maker (the plant) as an open-loop control system. The user provides the right amount of coffee and water, which are the inputs. The plant heats the water and controls the flow of hot water into the filter basket. The output is coffee. Assuming the plant is in proper working order, the quality of the coffee the output is determined by the quality of the inputs

TYPES OF SENSORS

Sensors can be directly or remotely connected to the controllers. They do this either via digital or analogue circuits. Sensors send data to the controllers and they can react by changing actuators settings.

Solenoid

a coil of wire with an electric current in it

Process

Driving a car is an example of a process. Here are examples of the elements.​ Inputs: Examples of inputs include speed, direction, and proximity to other cars.​ ​ Actions: Examples of actions include accelerating, braking, and steering the car. All of these actions create a system, known as driving. Outputs: Examples of outputs would be the correct speed, direction, and proximity to other cars and obstacles.

an electrical circuit

An Electrical Circuit is a physical network (or model of a physical network) of interconnected electrical components including batteries, resistors, capacitors, inductors, and switches

Light Emitting Diode

A Light Emitting Diode is a special purpose diode that emits energy in the form of light when properly forward biased. These devices are used for flashlights, lighting, and as a replacement for incandescent lamps. As current is increased, the brightness of the LED increases until a maximum current is reached.

controlled system

A heater in the thermostat feedback loop can be actuator since it changes the temperature after receiving electrical instructions.

Raspberry Pi (RaPi)

A low budget, pocket sized computer which is easy to program. This is a controller that can work without internet and is used by hobbyist or professionals.

Hexadecimal Number System

A number system consisting of 16 distinct symbols — 0-9 and A-F — which can occur in each place value.

Actuators

An actuator is a type of motor that is responsible for creating movement. Two examples of electrical actuators that are included in the SIK are shown in the figure.​​ An electric actuator converts electrical energy into mechanical torque. In this course, we will be only working with electric actuators, but actuators can also use hydraulic (oil), pneumatic (air), and mechanical power.

Atoms

Atoms are the building blocks of all elements and matter. Electrons carry negative charges and are attracted to the positively charged protons within the nucleus of the atom.

Clothes Dryer: A Close-Loop Control Systems

Clothes Dryer: A Close-Loop Control Systems Another example of a closed-loop control system can be found in newer models of clothes dryers. These dryers contain sensors that detect the relative humidity as clothes are drying. In this example of a closed-loop control system, the error state would be the sum of the desired dryness minus the measured dryness. This error is continually fed into the controller to make the necessary corrections in the plant, which reduces the error on the next iteration. This process continues until the clothes are dry, and the controller stops the plant.

Diode

Diode: The diode is a one-way valve that allows current flow in one direction only.

Ground

Ground: Provides the pathway to close the loop in a circuit.

Actuators

Its a basic motor with special instructions that help control an object.

Lamp

Lamp: Symbol represents a light bulb

positive feedback

Positive Feedback This feedback reinforces the original input. Positive feedback accelerates the transformation of the output in the same direction as the previous result. It tends toward either exponential growth or decline. Example: Population growth follows these tendencies.

Power

Power is the amount of energy consumed over time. Power is measured in Watts. The basic formulation of power is power = voltage x current.

Resistor

Resistor opposes electric current passing through it. Resistance is measured in Ohms (Greek letter omega Ω)Symbol:(R).

Final Words on Actuators

Robotics are used in many industries as part of automation. Robotic ARMs utilize actuators and sensors in many applications. The following video shows how robotics is used in manufacturing. ​

Pneumatic Actuator

Uses air pressure applied to a piston to shift the valve spool. Uses compressed air to perform mechanical operations.

HYDROLIC ACTUATOR

Uses fluid pressure to perform mechanical operations.

Voltage

Voltage is the force that drives current. It can also be referred to as electric pressure. Voltage is measured as the difference in electric potential energy between two points.

Digital Number (DN)

consists of zeros and ones only!

Transducers

A transducer is a device that converts energy from one form to another. A typical light bulb converts electrical energy to optical energy, and a heating coil converts electrical energy to heat. ​​ There are numerous devices we use in our daily life that coverts energy from one form to another. One example would be a cell phone, which has two types of basic transducers. ​​ A microphone: Convert sound to electrical signals​ A speaker: Convert electrical signals to sound ​​ Transducer Types​ Electroacoustic​ Electrochemical​ Electromagnetic​ Electromechanical​ Optical​ Photoelectric

Analog Circuits Versus Digital Circuits

Analog circuits are circuits in which current or voltage may vary continuously with time to correspond to the information being represented. Analog circuits are used in power management circuits, sensors, amplifiers, and filters.​ Digital circuits have electric signals that take on two discrete values corresponding to the level of voltage. These values are binary and are represented as 1/0, on/off, or high/low. ​ ​ In digital circuits, binary encoding is used: one voltage represents a binary 1 and another voltage usually a value near the ground potential, or 0 volts, represents a binary 0, as shown in the figure. ​ ​ Digital circuits can be designed to provide both logic and memory by interconnecting these binary signals, enabling them to perform arbitrary computational functions. ​ Integrated circuits are miniaturized circuits produced on a single piece of semiconductor. Integrated circuits are often referred to as chips and can have hundreds to billions of electronic components embedded into a single chip. PreviousNext

More on Interdependent Systems

Another example is the earth's climate system. Rising global temperatures cause arctic ice to melt faster, thereby increasing the amount of ocean surface. Increased ocean surface means less sunlight is reflected back into space, which increases the temperature of the earth.​ Finally, consider the example of recycling materials back into the supply chain. ​ Learn about how Dell is recycling the plastic from old electronics back into the supply chain, which is used to manufacture new computer systems at http://snippets.energyts.com/snippets/20140605/story7.html

Chemical Elements

Chemical Elements on the periodic table are made up of different types of atoms. The attraction between atoms and their outer electrons is stronger in some elements than in others.

Derivative Controllers (PID)

Derivative Controllers (PID) These proportional, integral, and derivative controllers include data about how quickly the system is approaching the desired output. In an HVAC system, the derivative function of a PID controller looks at the rate of change in temperature. This allows the controller to quickly adjust the output as the system approaches the desired output, as shown in the PID graph.

Dishwasher: An Open-Loop Control Systems

Dishwasher: An Open-Loop Control Systems Another example of an open-loop control system is a home appliance, such as a dishwasher. A dishwasher (the plant) typically runs for a set amount of time using soap and hot water (the inputs). The plant, with its optimally-placed spraying jets and dish racks, produces clean dishes (the output). However, the plant has no ability to determine when or if the dishes are clean. The plant will run its full cycle regardless of the quality of the input. Did the user load exceptionally dirty dishes? Did the user add soap?

Electric Current

Electric Current is created from the movement of electrons. Current flows in a closed loop and is constant everywhere in that loop.

Electrical Insulators

Electrical Insulators are materials made up of elements that strongly attract their electrons and in which the electrons never leave the atom. Examples of materials that are electrical insulators are dried wood, glass, and various rubber materials.

Active non linear circuits

Electronic components that produce energy are active and create nonlinear circuits.In a circuit, an active component is a device that can control electric current with an external source of energy, either electric voltage or electric current. The part of the circuit that provides energy to the active component is called the direct current (DC) part of the circuit.An active circuit is a circuit with at least one active component. Active components provide power gain or amplification that produces voltage signaling that is discontinuous or nonlinear. Active components include diodes, transistors, and silicon controlled rectifiers (SCRs).Examples of nonlinear circuits are mixers, modulators, and digital logic circuits.

HVAC: A Close-Loop Control Systems

HVAC: A Close-Loop Control Systems Initially, the digital thermostat is programmed with the desired temperature. This input is fed into the HVAC plant. If necessary, the plant engages the HVAC equipment, to generate the desired output. The resulting output is measured against the desired input. The error, or difference, between the desired and measured temperatures is determined and the thermostat adjusts the control to the HVAC plant.

The figure displays a sample IoT topology that highlights how controllers are used in fog computing. ​

Here sensors send information to the controllers who in turn pass information to actuators to see the traffic flow and manage signals to optimize the traffic issues within the LAN. Imagine smart traffic lights that contain sensors and actuators. The sensors detect and report traffic activity to the controller. The controller is able to process this data locally and determine optimal traffic patterns. Using this information, the controller will send signals to the actuators in the traffic lights to adjust traffic flows. This is an example of machine-to-machine (M2M) communication. In this scenario, the sensors, actuators, and the controller all exist within the fog. That means that the information is not sent beyond the local network of end devices.​

A process uses inputs to execute the right actions to achieve the desired output. More formally, a process is a series of steps or actions taken to achieve a desired result by the consumer of the process. A system is a set of rules that govern the series of steps or actions in the process.​

IoT devices can be smaller than a wristwatch or larger than a car. It may be for a simple sensing function that sends raw data back to a control center. It may collect and combine data from many sensors. Performance of local data analysis, decision making, and action may also take place. Devices could be remote, standalone, or distributed within a larger system. Regardless of the arrangement, location, function, or environment, an IoT device requires two components—a controller or brain and connectivity or pathway to distribute information. The "brain" allows local control (or decision making). The size and capabilities of the brain component will depend on its function. Connectivity, that is, a network is needed to communicate with external inputs and or outputs. The environment and location of a device will determine how it connects.​

Open Loop Control System

Open-Loop Control Systems Open-loop control systems do not use feedback. The controller instructs the plant to perform a predetermined action without any verification of the desired results. A logic diagram of an open-loop control system is displayed in the figure.​ ​ Open-loop control systems are often used for simple processes where the relationships between the input and the plant are well-defined. The job of the engineer is to determine how to manipulate the inputs so that the plant will generate the desired outputs.​ ​ontrol System

More Actuators

There are electronic components that can be used to provide greater amounts of electric current to run large motors and machinery. The magnetic field produced by current running through a coil of wire can be used to exert a mechanical force on any magnetic object. The magnetic force can be turned on or off by switching the current on or off through the coil.​​ If you place a magnetic object near the coil for the purpose of making the object move when you energize the coil, you have a solenoid. ​​ The movable magnetic object is called an armature. Solenoids can be used to electrically open door latches, open or shut valves, move robotic limbs, and even actuate electric switch mechanisms. ​​ If a solenoid is used to actuate a set of switch contacts, this is called a relay.

Sensors

These devices can measure physical properties of light, motion, pressure, temperature moisture, or any other environmental condition from the physical world. For example, in figure right, the coffee farm displayed could use sensors to collect a variety of information, such as sunlight, temperature, and soil moisture. This data can then be analyzed to help maximize the yield and quality of coffee beans.​​

Sensors can act as a gateway to IP networks

They help data to be analyzed or stored in fog or cloud. This can in turn help people, machine and various system to use this for any other action. For example analysis of birthrates in a country may encourage government to a open a new school in a different location.

Controllers

They receive data from sensors and provide internet or network connectivity. They can directly make decisions or follow up with a larger computer for analysis. This computer may be in LAN or could be connected via internet connection. In this picture router is setting up the communication between controller and the computer.

Electronic Components and Circuits - Transistor II

Transistor as a switch is used in digital applications​. ON represents a High ( Binary "1") and OFF represents a Low (Binary "0"). The two states in binary logic are the foundation for digital logic.​ ​ Several logic gates are developed based on the use of transistors as switches. ​ ​ Figure 1 shows the picture of a transistor configured to work as a switch. One example would be an Inverter (Not gate). The digital logic symbol for an inverter is shown below.​

Voltmeter:

Voltmeter: Measures voltage where voltage is the electrical pressure that causes a current flow (movement of electrons/time) through a completed electrical circuit; that is, the energy per unit of charge. Voltage is measured in volts. Symbol:(V).

Sensors can detect Gas

for example: Oxygen, monoxide, methane, Carbon dioxide, hydrogen, hydrogen sulfide, ammonia

Electrical Actuator

powered by motor that converts electrical energy to mechanical operations

Interdependent Systems

Closed-loop control systems are simple to understand; however, there can be considerable complexity in the real world. Many factors can impact systems, and the extent of their impact is not always easily measured. Most systems have many interdependent pieces contributing to and affecting the output.​ For example, consider a healthy lifestyle system. A person embarks on a program of diet and exercise. After a short time, they become stronger and their clothes fit more loosely. They begin to receive compliments (feedback) from others. This results in good feelings that motivate them to continue their diet and exercise.​

DC voltage source

DC voltage source: Symbol is used to represent a battery or a dc voltage source.

Basic Circuit

Electronic devices all share a fine level of control of electrical energy. This control happens through the electronic circuit. A circuit is a closed conductive path that allows electrons to flow and create an electric current. To create an electric current the circuit also needs an electrical energy source, such as a battery, to start the flow of electricity. ​ A closed circuit allows current to flow. An open circuit has a break in the pathway that stops the current from flowing. An open circuit can be created by placing a switch along the circuit pathway. Any electrical device with an on/off switch creates a circuit that can be closed or opened.

Series and Parallel Circuits

In a series circuit, the components are interconnected one after another in a path between the positive and negative terminals of the power source, as shown in the figure. The electric current travels through each component in a linear fashion.An example of a series circuit can be seen in a string of decorative holiday lights with each light connected to the next, one right after another.Although the decision between series or parallel circuits depends on the application, the power supply must be powerful enough to provide power to the entire circuit in both cases.

Sensors

Sensors are devices that detect an event from the physical environment and respond with electrical or optical signals as output. There are sensors that measure light, moisture, motion, pressure, temperature, or other environmental properties.

More on Controllers integration

Some controllers can take more tasks other then passing information from M2M. They can be a part of much larger IP networks to perform much complex operations. Some can take information from more then one sensor and analyze data before sending actuator those instructions.

Electronic Components and Circuits - Variable Resistor (Potentiometer)

To determine resistance a potentiometer can be used. A potentiometer is a variable resistor with three terminals. The resistance between any two terminals can be varied within the limits of the resistor. ​ ​ Looking at the diagram, if we move the arrow, or wiper, to change the resistance values, the potentiometer resistance from A to B = Rconstant​ RAB + RBC = RAC, RAB can vary from 0 to RAC​ Variable resistor (Potentiometer) The variable resistor or potentiometer is drawn in several different ways. The symbol is often drawn as a resistor with an arrow across it or pointing down on it as the one below.​ ​

Transformer

Transformer: The transformer converts the 120VAC to a lower AC voltage.

Controller Area Network

A bus standard for use in vehicles to connect micro-controllers. So most of the time cars have microcontrollers in them that can directly communicate with sensors and help perform the task without a outside or host intervention. For example Backup camera's or anti-collision sensors. These camera's and there sensors can alert the microcontrollers if an object is on its way and they can react buy alerting the car by emitting a warning signal or automatically applying brakes.

Capacitors

A capacitor consists of nothing more than two conductive plates separated by an insulator material, which is called the dielectric. Figure A shows a dielectric. Figure B shows capacitors that can come in different forms, which are the following.​ A fixed capacitor does not vary in its capacitance value. ​ A variable capacitor may be adjusted within a specified range of capacitance.​ A polarized capacitor is referred to as an electrolytic capacitor. Special attention needs to be given to the polarity of the leads when placing an electrolytic capacitor in a circuit since one lead will have a positive polarity and the other lead will have a negative polarity.​ ​ When a capacitor stores a high volume of charges (High Voltage), then it has the potential to be dangerous. It is important to remember that even if a capacitor is not connected to a circuit, it can still retain a charge.

Electronic Components and Circuits - Microcontroller (Complex Ics)

A computer can be programmed to detect an event that was triggered by a sensor and then perform an action based on that event. Microcontrollers are a great platform for performing these tasks due to their miniature size and meager power requirements. ​​ A microcontroller unit (MCU) is a simple computer designed and built in a small form factor. When paired with sensors or actuators, microcontrollers can be programmed to act based on triggers. The Arduino, shown in Figure 1, is a popular microcontroller for prototyping. ​​ Arduino boards are able to read inputs, such as light on a sensor, a finger on a button, or a Twitter message. They can then turn the input into an output, such as activating a motor, turning on an LED, or publishing something online. All of this is defined by a set of instructions programmed through the Arduino integrated development environment (IDE). ​​ Notice how everything is integrated on a printed circuit board.​ ​

A control system

A control system includes a controller that uses inputs and outputs to manage and regulate the behavior of the system in an attempt to achieve a desired state. ​ The input specifies what the output should be for the whole process. The controller indicates what specific changes are needed to achieve the desired output based on the input. The Plant: The controlled portion of the system, the process and the actuator, is often called the plant. The input is used by the plant to produce the desired output. Control Theory: Choosing the adjustments to apply to a plant to achieve a desired output is called control theory.​

numbering system

A way of representing numbers Decimal 0-9(Has base 10 and you can create infinite numbers) binary= 0 and 1 only(Has base 2) octal(Has base 8) 0-7 hexadecimal(Has base 16)0-9 and A-F

Ammeter:

Ammeter: Measures current where the current is the flow of electrons through a circuit. It is also defined as the amount of electric charge (measured in Coulombs) through a surface over time, or the rate of flow of charge. Current is measured in amperes or amps(A).

Amperes (Amps)

Amperes (Amps) measure the strength of electric current. Amperes are a measure of the number of electrons in an electric current. One ampere per second is equivalent to one coulomb traveling through a circuit in one second. This is roughly equivalent to the flow of 6.241509×10^18 electrons per second.

Inductors

An Inductor is an electronic component that stores electric energy and opposes a change in current.​ If we wrap a very long piece of thin wire around a nonconductive cylinder, what we have made is called an inductor. It is also known as a coil, a choke, or a winding. When an inductor is connected to a voltage source and current flows through the coil windings, a magnetic field is generated composed of imaginary lines called magnetic flux. The magnetic field changes as a response to a change in current. As current is increased through the inductor, the magnetic field expands outward, and as current is decreased, the magnetic field collapses inward. Identifying the Inductance Value of an Inductor The inductance value of large inductors is often printed on the body of the inductor. However, smaller inductors use a color-coded identification scheme that is similar to the resistor color code. Most inductors use four-color bands and the unit of inductance is typically in mH. When measuring the resistance of an inductor with a DMM, it will be low resistance.​

Closed-Loop Controllers Continued II

As mentioned earlier, the acronym PID stands for proportional, integral, and derivative. Each of these terms describes how an error is handled. Although the math is beyond the scope of this course, the meaning of these terms can be explained using the figures right.​​ Note that proportional control can be implemented with pneumatic, analog, or electronic controllers.

Capacitor

Capacitor: An electronic component which stores electric charges and opposes a change in voltage.

Closed-loop control systems

Closed-loop control systems uses feedback to determine whether the collected output is the desired output.​ A closed-loop system measures output using a sensor. Using control theory, this measurement is compared to a reference that represents the desired state (input). The result is then fed back into a controller. This feedback is used by the controller to adjust the controls into the plant for the next iteration of output, and the process repeats. ​ ​ A closed-loop control system can continually adjust the output based on the desired state (the input) and measured state from the previous loop through the system. There are many examples of closed-loop control systems, such as home heating, ventilation, and air conditioning (HVAC) control system and a clothes dryer.​

Passive non Linear

Components that store or maintain energy are passive and create linear circuits. Components that are incapable of controlling current by means of another electrical signal are called passive devices. An electronic circuit consisting entirely of passive components is called a passive circuit.Resistors, capacitors, inductors, and transformers are all considered passive devices. Passive components cannot introduce energy into a circuit. They also cannot rely on a source of power, except for what is available to them from the circuit they are connected to. Passive components cannot amplify the power of a signal, although they may increase the voltage or current. The signal processing in a passive circuit is continuous or analog.Analog circuits are circuits where the signal is contiguous; it can assume any value between no power to full power.Digital circuits present a discrete signaling, assuming either no power or full power values ("all or nothing"), with no intermediate steps.A linear circuit is one in which the values of the electronic components (resistors, capacitors, inductors, etc.) do not change with the level of voltage or current in the circuit. Linear circuits are important because they can amplify and process electronic signals without distortion.An electronic device that uses linear circuits is a sound system. A linear circuit is one that has no nonlinear electronic components in it.Examples of linear circuits include amplifiers, differentiators, integrators, and linear electronic filters.

More on Control System

Control theory is applied in all types of devices. Consider how control theory is applied when driving a car. ​ The driver of the car is the controller, managing and regulating the car (the plant). ​ Based on the input, the driver determines how to use each control (e.g., accelerator, brake, steering wheel) to achieve the intended output. Many of the processes in a car also depend on control systems designed by the automobile manufacturer. In these control systems, the output is measured using some type of sensor to inform what changes a controller needs to make. ​ The goal is to design a system with an error rate of 0. This means that the output of the plant is exactly what you want it to be. Therefore, if a driver wants to travel at 65 mph, then setting the cruise control to 65 mph should achieve exactly that result.​

Direct Current Versus Alternating Current

Direct current (DC) is a type of current in which the flow of electrons goes one way only. Direct current is produced by sources such as batteries, power supplies, thermocouples, solar cells, or dynamos. ​Direct current is used to charge batteries and as power supply for electronic systems. Direct current can be obtained from alternating current by using a rectifier to convert AC into DC. Rectifiers force current to flow in one direction only and are commonly found in an AC to DC power supply. ​ Alternating current (AC) is an electric current in which the flow of electric current periodically reverses direction. AC is the form in which electric power is delivered to businesses and residences. The usual waveform of alternating current in most electric power circuits is a sine wave. In certain applications, different waveforms are used, such as triangular or square waves. ​Alternate current is produced in the electrical power plant by taking advantage of various forms of mechanical energy (water flowing from a dam or the spin of a wind turbine) to move large scale alternators. The alternators then transform the mechanical energy into electricity. Direct current produced by a solar plant may be converted into alternating current with an inverter or a motor-generator set​.

Electrical Conductors

Electrical Conductors are materials with elements that have a weak attraction between atoms and their electrons. In conductive elements, electrons tend to move from atom to atom. Examples of electrically conductive materials are metals like copper, gold, and silver.

Three types of Actuators

Electrical, pneumatic and Hydraulic

Survey of Components

Electronic components are specialized devices used in a circuit to control current. Some examples of electronic components are wires, switches, resistors, capacitors, diodes, transistors, inductors, and integrated circuits, as shown in the figure. ​ Electronic components have two or more electrical terminals or leads. The leads connect to create an electronic circuit with a particular function, such as an amplifier, radio receiver, or oscillator. Electronic components can be individual items, arrays or networks of like components, or integrated inside of packages such as integrated circuits.​ As a reminder, these are the most common components. Resistors​ Capacitors​ ​ ​ LEDs Transistors Inductors Integrated Circuits (simple to complex circuits all in one package (such as a microprocessor chip)​ These components can be reduced to very small sizes for use in devices, such as a smartphone, or can be increased in size for industrial use, such as an HVAC system.​

Electrons

Electrons along with protons and neutrons are what make up atoms. The basic charge on an electron is measured in terms of coulombs. One coulomb of charge is equal to the amount of charge carried by one ampere in one second.

Types of Feedbacks

Feedback is often referred to as a feedback loop. This is because the input results in output that is continually resampled and used as new input. The feedback loop represents the idea of a cause-and-effect cycle, or circuit, where results continually adjust actions. ​ Many system processes normally have some type of feedback loop mechanism. Systems usually have a way of looping or feeding back information about the quality of the output. ​ Feedback loops can be positive or negative.

Feedback

Feedback is when the output of a system, or process, affects the input. ​ Consider how feedback was used to safely land on the moon. The computer continually received altitude and speed feedback measurements.​ This information was displayed to the astronaut through the onboard systems. The astronaut used the feedback to control the spacecraft and adjust altitude, engine, and thrust levels to successfully land on the moon.​

Basic Definitions and Concepts/ State Diagram

State Diagram: A state diagram graphically shows the following.​ The sequence of states (like on or off) ​ The conditions for each state (is it on or off right now) ​ The requirement for transition from one state to the next state (what is the rule to turn from on to off or vice versa)

parallel circuit

In a parallel circuit, current flows from the battery terminal, but splits at a junction which leads to parallel pathways through the circuit. Components connected along each pathway each get their own share of current, as shown in the figure.In a parallel circuit you can power multiple components such as LEDs; however, because each component gets its own supply of current. If any one component or LED were to fail, it would not stop the current from flowing to the other pathways and powering the other components or LEDs.For example, a parallel circuit could solve the common problem of a holiday string of lights, that when one light fails.Although the decision between series or parallel circuits depends on the application, the power supply must be powerful enough to provide power to the entire circuit in both cases.

short circuit

In contrast to closed circuits and open circuits, a short circuit is usually not created by design. A short circuit happens when an unintended connection between two points in the circuit bypass the normal pathway. Because electrical current normally takes the path of least resistance, short circuits can cause too much current to overload components. This causes overheating and results in unsafe scenarios such as melting wires, component failure, and the possibility of electrical fire.

Inductor

Inductor: An electronic component which stores electric energy and opposes a change in current.

Integral Controllers (PI)

Integral Controllers (PI) These proportional and integral controllers use historical data to measure how long the system has deviated from the set temperature. The longer the system has deviated from the set temperature, the larger the response from the controller. In an HVAC system, the controller would account for historical data and time when adjusting the system. Although integral controllers will also overshoot the set temperature, the variation will decrease overtime, as shown in the PI graph.

Integrated Circuits

Integrated circuits come in many varieties. These are simple circuits to complex circuits packaged in a single chip. Transistors, resistors, and capacitators in a circuit can be integrated into one single IC chip. In IOT, various drivers and controllers are very often integrated into a single IC chip. IC chips come in various varieties and configurations and they fall into two categories: through hole (PTH) or surface mount (SMD/SMT). DIP (Dual in-line packages) are the most common through-hole IC packages used. Surface-mount packages are used in custom-printed circuit boards and comes in different types such as. Small-Outline Package (SOP) Shrink-Small Outline Package (SSOP) Quad flat package

Negative Feddback

Negative Feedback This feedback cancels out or counteracts the original input. Negative feedback diminishes the effect of the previous result. It tends towards stabilization, reaching some level of equilibrium or homeostasis. An example of this is how a rooms temperature is controlled.

How Computing Devices, that is, Digital Devices Work​

Modern digital devices are revolutionizing our lives and performing tasks unimaginable only decades ago. They all rely on the integration of all these electronic parts discussed previously, with the transistor being the most important element! So how does it all come together? Watch this video and find out.

Motor

Motor: Symbol represents a motor.

Light Emitting Diode (LED)

Now let's learn about light emitting diodes (LED). You probably commonly hear this referred to by the acronym spelled out as L-E-D.​ A diode is a one-way valve that allows current flow in one direction only. The schematic symbol is shown in the figure. ​

Ohm's Law

Ohm's Law Digital devices are electronic, so they need a variety electronics devices arranged in circuits and electric power to work. If your goal is to design, create, and analyze electrical circuits, then it is important to understand the relationship between voltage, current, and resistance within a circuit. ​ In the 1800s, George Ohm discovered that voltage is constantly proportional to current in a circuit with a fixed source of resistance. Ohm published his theory, which has become a fundamental concept in electronics, known as Ohm's Law. The world of IoT is based on several technologies, one of which is increasing availability of low cost electronics sensors.​ According to Ohm's Law, voltage is directly proportional to the strength of current multiplied by resistance within a circuit. Simply stated, voltage equals current multiplied by resistance (V = I x R), as shown in the figure.

Proportional Controllers (P)

Proportional Controllers (P) These controllers look specifically at the difference between the measured output and the desired output. The amount of change sent to the plant by the controller is proportional to the size of the error from the last iteration. For example, in an HVAC system the controller would activate 50% of the chillers if the sensor detected a one degree deviation from the set temperature. At 2 degrees deviation, 100% capacity would be activated. Proportional controls will usually overshoot the set temperature, as shown in the P graph because they are only looking at the deviation from the set point at any given time.

Even More Actuators

Relays are extremely useful when you have a need to control a large amount of current and/or voltage with a small electrical signal. The relay coil that produces the magnetic field may only consume fractions of a watt of power, and the contacts closed or opened by that magnetic field may be able to conduct hundreds of times that amount of power to a load.​​ The relay's coil is energized by the low-voltage (12 VDC) source, and the single-pole, single-throw (SPST) contact interrupts the high-voltage (480 VAC) circuit. It is quite likely that the current required to energize the relay coil will be hundreds of times less than the current rating of the contact. ​​ Typical relay coil currents are well below 1A (1 ampere), and typical contact ratings for industrial relays are at least 10A (10 amperes).​ A relay is an electrically controlled mechanical switch. The image shows a relay that is included in the SIK. Inside that plastic box is an electromagnet that causes a switch to trip when it receives a current.

Transistors as an Amplifier​

Transistor circuits are widely used as amplifiers. An amplifier means that the output signal is the amplification (being greater) than the circuit input signal, or when a signal goes into and through the circuit, the power of the signal gets amplified. Generally, this amplification is in terms of AC signals, due to the factor that the BJT circuit is powered by DC power source.​​ BJT Amplifier Types Common Emitter Amplifier​ Common Collector Amplifier​ Common Base Amplifier​ Class A Amplifier​ Class B Amplifier​ Class AB: Push Pull Amplifier​ Class C Amplifier​ Class D Amplifier

Resistors

Resistors, as the name suggests, are components that resist the current. Although very basic, the resistor is actually extremely useful. For example, a resistor can be used to control the voltages and the current in a circuit, which is very important in regulating power consumption or damage to a device. Let's look at a LED device in series with a battery and a resistor. If you connect the battery directly to the LED, lots of current will flow through the LED, but the LED will not last long as this is much more than the LED can handle. It will become very hot and quit working after a short amount of time. You can use Ohm's law to determine just how much current is actually need to the device needed.

Sounds and Sparks!

Sounds and Sparks! A capacitor will release its charge in a short period of time once the two plates are connected directly by shorting the terminals. This can create a loud sound and a spark that can burn skin and cause harm to eyes. However, the capacitors that are used in your experiments will not be connected to high voltages; therefore, they are considered safe.

State Machines

State Machine: A sequence of events that can be implemented in a logic system is called a state machine. The output of a state machine follows a predictable sequence, triggered by a clock (or particular timing that that is desired) and other input conditions.​ State machines are represented using state diagrams. For example, a simple state machine illustration of a traffic light is shown.​ State machines can play a significant role in many fields of study, such as electrical engineering, linguistics, computer science, philosophy, biology, mathematics, and logic. ​They are ideally suited for representing or modeling behavior, software, digital systems, and networks.

Switch

Switch: A switch opens or closes the path of current flow in a circuit.

Thermal sensors

Temperature sensors will detect temperature or heat. One example would be the thermostat, which monitors the ambient temperature in our homes. These sensors measure the amount of heat energy or even coldness that is generated by an object or system, allowing us to "sense" or detect any physical change to that temperature producing either an analogue or digital output.Contact temperature sensors require physical contact with the object being sensed and use conduction to monitor changes in temperature. They can be used to detect solids, liquids, or gases over a wide range of temperatures.Non-contact temperature sensors utilize convection and radiation to monitor changes in temperature. They can be used to detect liquids and gases that emit radiant energy as heat rises and cold settles to the bottom in convection currents or detect the radiant energy being transmitted from an object in the form of infrared radiation (the sun).The thermostat is a contact type electromechanical temperature sensor that basically consists of two different metals that are bonded together to form a bi-metallic strip.

Basic Circuits Continued

The figure also depicts a battery to power a light-emitting diode (LED). In the figure, you see a circuit diagram, or schematic, that shows all the components of the circuit and how they are connected.​ ​ The LED is symbolized by a triangle with a line segment on one end and two arrows pointing outward. The triangular part of the symbol represents a diode, and the two arrows facing out represent the fact that this diode emits light. Diodes are part of a special class of electronic components known​ ​ The battery supplies 6 volts of direct current to the circuit. The plus sign near the battery symbol indicates the positive terminal of the battery. According to an early understanding of electricity known today as conventional current, electric current is positively charged and flows from the positive terminal to the negative terminal. ​ ​ This is indicated in schematics that use conventional current by an arrow and the letter I. This labelling convention is still used today, even though it is now understood that the flow of current is the exact opposite: electric current flows from the negative terminal to the positive terminal and is made up of negatively charged electrons. Most schematics will use conventional current even though the flow of electrons is the opposite of what is shown. In this course, we will use conventional current to describe the flow of current but remember that, in actuality, the electron flow is the exact opposite. ​

Basic Circuits Continued

The lines in the circuit diagram show how the circuit components are connected using wire or other connectors. Electronic components are usually made with leads. Leads are protruding wires that connect to the inside of the component and provide the means to connect the component to other circuit elements. The zigzag symbol at the top of the diagram represents a resistor. The role of the resistor is to limit the amount of current that flows through the circuit. Resistance is measured in ohms (symbolized as Ω) and the resistor in this circuit helps to keep the LED from receiving too much current and being destroyed.

Arduino Microcontroller

This is a controller that can work without internet and is used by hobbyist or professionals. The key difference between Raspberry Pi and this is the size, OS, memory power, available processing power. It depends on application which one is best. They both can be used together. For example data might be collected in Arduino but processed is RaPi.

Electronic Components and Circuits - Transistor

Transistor operation is a cornerstone of electronic theory, and the creation of the transistor ranks as one of the most important inventions of the 20th century. Transistors were developed in the late 1940s by engineers at Bell Labs. At the time, no one truly realized the impact transistors would eventually have on the world.​ The days of bulky vacuum tubes with heaters are gone. The discrete transistor has evolved, and we now have micro technology that creates the silicon semiconductor chips that are the mainstay of integrated circuits. This technology makes your personal computer possible and the other sophisticated electronics applications that are available today.​ Bipolar junction transistor (BJT): The bipolar junction transistor has a variety of purposes. It is a driver for operating a motor, an amplifier for increasing the amplitude of a signal, or a simple on-off switch. The difference between a BJT and a Field Effect Transistor (FET) is shown below.​ Comparison Between BJT and FET

Transistor

Transistors are commonly used as simple switches in electronic circuits. A transistor conducts current across the collector-emitter path only when a voltage is applied to the base. A switch is: OFF - when no base voltage is present. ON - when base voltage is present. In an ideal switch, the transistor is in only one of two states: off or on. When there's no bias voltage or when the bias voltage is less than 0.7 V, the transistor is off. When the base is saturated so that collector current can flow without restriction, the switch is on.

Electonics

We use electronic devices every day, from cell phones to TVs, to many of our various tools and appliances. How often do we stop to consider what the field of electronics is? ​ Electronics is the field of study focused on the control of electricity and the physical components and circuits that help direct electrical energy. The word electronics is derived from the word electron, which is the source of electric charge. ​ The world of IoT is based on several technologies, one of which is increasing availability of low cost electronics sensors.​ A sensor is an electronic component that transforms a physical quantity, such as the temperature in the room, the position of a robotic arm, or the sugar level in the blood, into an electrical signal. The electrical signal that the sensor generates is then transformed into a digital signal to be processed by a very simplified computer system called a microcontroller. This lesson covers the basic understanding of how electronics is required to prototype an IoT solution.​ ​ If you wish to know how electronic devices control electric current, you need to have a basic understanding of what electric current is.