SDD yearly

Question 1

microcontroller unit

Answer 1

A microcontroller unit (MCU) is a single-integrated circuit. This small self-contained computer is designed to perform a specific task in an embedded system.

Question 2

General-Purpose Input Output (GPIO) pins

Answer 2

add other electronics to expand the possibilities of the micro:bit.

Question 3

GND pin

Answer 3

used to complete electrical circuits

Question 4

A sensor

Answer 4

A sensor is a device that detects and converts a non-electrical input to an electrical signal, uses an appropriate transducer to measure an environmental quantity and converts it into an electrical signal appropriate for use in common microcontrollers.

Question 5

accelerometer

Answer 5

An accelerometer is a sensor that measures the vibration, or acceleration of motion of a device. They use piezoelectric transducers that convert physical movement into electrical signals.

Question 6

An actuator

Answer 6

An actuator is a part of a device or machine that helps it to achieve physical movements by converting energy, often electrical, air, or hydraulic, into mechanical force. So, an actuator’s functionality is opposite to that of a sensor

Question 7

Open Loop Control:

Answer 7

There is no feedback system to control the action.

Question 8

Closed Loop Control:

Answer 8

A feedback mechanism exists to control the action.

Question 9

microprocessor/CPU Components:

Answer 9

ALU (Arithmetic Logic Unit): Performs arithmetic and logic operations.
Registers: Temporary storage locations for data and instructions. Port registers allow for lower-level and faster manipulation of the i/o pins of microcontrollers.

Control Unit: Directs the operation of the processor by interpreting instructions from memory and controlling other components.

Question 10

Memory (RAM), Bus and IO ports

Answer 10

Memory (RAM): Stores data and instructions that are currently in use.
Bus: The communication pathway that transfers data between the CPU, memory, and I/O ports.
I/O Ports: Interfaces for input and output operations, allowing the microprocessor to interact with external devices.
The Bus and I/O Ports are not part of the CPU itself. The Bus is a communication pathway that connects the CPU with memory and I/O devices, while the I/O Ports are interfaces for external communication

Question 11

instruction set

Answer 11

The set of instructions a particular microprocessor can execute is called its instruction set.
Instruction sets consist of binary codes but are usually described for human readers in a text-based assembly language

Question 12

translator

Answer 12

A translator changes high level source code such as C++ or Python into binary machine code for the embedded microprocessor in the microcontroller

Question 13

3 types of registers

Answer 13

DDR, PORT and PIN.
In addition, the chips used on the Arduino board (with 8 bit processor) have three ports (Reference):
B (digital pin 8 to 13)
C (analog input pins)
D (digital pins 0 to 7)

Question 14

Functionality of each type of register

Answer 14

A DDR register determines whether the pin is an INPUT or OUTPUT.
The PORT register controls whether the pin is HIGH or LOW.
The PIN register reads the state of INPUT pins.

Question 15

transducer

Answer 15

A transducer converts one form of energy into another. includes sensors and actuators

Question 16

Bit Rate

Answer 16

refers to the amount of data transmitted per unit of time in a digital communication system (no. digits per second)

Question 17

Baud Rate Definition

Answer 17

Baud rate indicates the number of times the signal’s state changes per second. (no. of groups of digits per second)

Question 18

A gyroscope sensor

Answer 18

measures and maintains the orientation and angular velocity of an object using Earth’s gravity to help determine the rotation on a particular axis.

Question 19

The I2C (Inter-Integrated Circuit)

Answer 19

a two-wire serial communication protocol using a serial data line (SDA) and a serial clock line (SCL)

Question 20

Ultrasonic distance sensors

Answer 20

essentially a “land sonar”: it emits a high frequency sound, far beyond what the human ear can hear, and waits for the echo.

Question 21

Light dependent resistors (LDRs)

Answer 21

These reduce their resistance as they are exposed to more light

Question 22

Phototransistors

Answer 22

These are based on transistors that have an input that is sensitive to light instead of an electrical voltage.

Question 23

Photodiodes

Answer 23

These are more basic transducers than phototransistors. It generates current when exposed to light. Are best used in combination with a transistor to help amplify the output signal as part of a light sensing circuit.

Question 24

Diodes vs transistors

Answer 24

A diode is an electrical component that is used to facilitate the flow of electrical currents in one direction. Transistors have the function of amplifying and switching electrical signals.

Question 25

Actuators

Answer 25

motors that produce rotational or linear movement

Question 26

end effectors

Answer 26

When more complex movement is desired, end effectors are used to convert the basic movement of an actuator, or a collection of actuators, to create more complex movement.

Question 27

Pulse Width Modulation

Answer 27

a technique for getting analog results with digital means. Digital control can create a square wave, which is a signal that switches between on and off. This pattern can simulate voltages between the board’s full voltage e.g., 5V on an UNO board and 0V by adjusting the ratio of on-time to off-time, known as the pulse width. By modulating the pulse width, you can achieve varying analogue values. When this on-off pattern is repeated quickly, it can control the brightness of an LED as if it were a steady voltage e.g.,

Question 28

A potentiometer

Answer 28

a three-terminal resistor with a sliding or rotating contact that forms an adjustable voltage divider.

Question 29

Rotary actuators

Answer 29

motors designed to produce rotational motion

Question 30

Servos

Answer 30

rotational actuators that are controlled by short pulses of voltage (can be positional 0-180 degrees or continuous)

Question 31

Stepper motors

Answer 31

the internal electromagnetic motor design of stepper motors allows very precise rotational movements to specific preset angles

Question 32

A linear actuator

Answer 32

A linear actuator is a device that creates motion in a straight line

Question 33

Analog-to-Digital Conversion (ADC)

Answer 33

This is the process of converting an analog signal into a digital (binary) form. An ADC inputs an analog electrical signal and outputs a binary number. This is crucial in applications like audio and video recording where the signals are inherently analog, but the processing is digital.

Question 34

Digital-to-Analog Conversion (DAC)

Answer 34

This is the reverse process of ADC. A DAC inputs a binary number and outputs an analog signal, such as voltage or current. This is used when the processed digital signal needs to be converted back to analog form, for example, playing digital music through speakers.

Question 35

key points on degrees of freedom:

Answer 35

Here are the key points on degrees of freedom:
Translation and Rotation: A rigid body in space can have up to six degrees of freedom: three translational (movement along x, y, and z axes) and three rotational (rotation around x, y, and z axes)1.
Constraints: Adding constraints to the system, such as joints or fixed points, reduces the degrees of freedom. For example, a robotic arm with multiple joints will have fewer degrees of freedom than a free-floating object.
Kinematic Chains: In mechanisms, the degrees of freedom determine how many independent inputs are needed to control the system. For instance, a simple robotic arm with three joints might have three degrees of freedom, meaning three independent movements are required to position the end effector.

Question 36

Autonomous control systems

Answer 36

Autonomous control systems are designed to operate independently without human intervention for extended periods. They use a combination of hardware and software to perform control functions, even in uncertain or dynamic environments. Three main types of autonomous control systems are: on-off, proportional and PID (proportional, integrative and derivative).

On-off autonomous control systems are a type of control system where the output is either fully on or fully off, with no intermediate states. * Operation: The system switches the output on when the process variable (e.g., temperature, pressure) falls below a certain threshold and switches it off when the variable exceeds a predetermined level.

Proportional control systems set the size of the response based on the difference from the desired setpoint. The bigger the difference, the bigger/faster the response.

A PID controller (Proportional-Integral-Derivative controller1. Proportional (P): This part of the controller produces an output value that is proportional to the current error value (difference between the output and expected output).2. Integral (I): This part of the controller accounts for past values of the error. It integrates the error over time, which helps eliminate residual steady-state error that occurs with a pure proportional controller.3. Derivative (D): This part of the controller predicts future error based on its rate of change. It provides a damping effect, which helps reduce overshoot and improve system stability.

Question 37

Analogue to digital conversion process

Answer 37

SQED
Sampling (takes a snapshot/sample of analogue signal)
Quantizing (divides sample into discrete steps)
Encoding (assigns digital codes to these steps)
Digital signal (outputs these codes in binary)

Question 38

Digital to Analog Conversion Process

Answer 38

ICO
1. Input: The DAC takes a binary equivalent of a fixed-point number as an input.
2. Conversion: Converts the binary number into its equivalent analog signal
3. Output: The DAC outputs the analog signal

Question 39

On/off digital sensor data

Answer 39

On/off digital sensors come with similar pinouts to analog sensors, but the output is either a high or a low voltage.
They are useful when the presence (or absence) of something needs to be indicated rather than a range of values describing something about the detection.
On/off digital data is most efficiently stored using a Boolean data type and can also be used directly within control structure conditions.

Question 40

Structured approach (Waterfall method)

Answer 40

Systematic, robust, fail-safe approach where every stage is thoroughly completed to the highest degree, with many resources, labour and capital allocated and employed
Work required to fix errors compounds with every stage skipped
More documentation (though passive not active) allows client to see progress of project, changes made to project typically take more than a month to be implemented

Question 41

Agility approach

Answer 41

Useful when changes occur during development of a project; e.g. government policies, competitor reveals new innovation, change in client requirements for end project
More reactive to changes and receive faster feedback from client
Less documentation (more active implementations), every 2 weeks new increment changes made to project
Prioritises speed of release, more interaction and working versions regularly delivered

Question 42

Prototype approach

Answer 42

Only a prototype, knowledge of requirements is never complete, instead evolves over time, unknown requirements start to emerge
Full fledged system is not built, only refined till requirements are found
Able to react to changes, unlike waterfall method, but only prototypes, unlike agility approach which is actually building the project
Different from agile, less teams working, limited documentation compared to agile

Concept prototyping:
Inspires discussion about implementation of product, customer requirements. Multiple prototypes may be presented to clients

‘Proof of concept’
Evolutionary prototyping:
Forerunner to final product
Each prototype improvement from last
Eventually ‘evolves’ to become final product

Question 43

RAD Approach

Answer 43

Purpose: Reduces time and money spent, typically using a non-customisable, automated tool such as MS access → reduces robustness
Less quality
Less coding, more visual projects
Best used for:
Standalone machines
Uses existing code and modules
Less reliability, performance and narrow use case
Not good for:
Interacting with other applications
Reliable, fail-safe software for wide-use distribution