Software development

8 stages of software development

1. requirements definition

2. determining functional and non-functional specifications

3. design

4. development

5. integration

6. testing + debugging

7. installation

8. maintenance

needs vs requirements

needs are general whilst requirements are specific and must be verifiable

what are requirements

features/properties/behaviours a system must have to acheive its purpose

what are functional specifications

performance, compatibility, functionality (what it does)

what are non-functional specificiations (5)

documentation, audience appropriateness, social/ethics, user interface, user experience

how are the needs of the client determined

survey, formal business analysis, observation, interviews

what is involved in design

algorithms and how data is stored (data types)

what is involved in development

code written and tested

what is involved in intergration

adding new code to system, inv. code being reviewed and tested to ensure compatibility

what is involved in testing and debugging

system level testing, volume testing, transaction types, response times

what is involved in installation

how users switch to new system, inv. training users + transitioning

what is involved in maintenance

updating code to fix bugs or support new hardware or add features, must then update documentation

development approaches

1. waterfall (highly structured and sequential)

2. agile (iterative, working versions continually released then feedback gathered)

what is modular design

seperating code into subroutines/subprograms/modules

benefits of modular design (5)

• breaks complex problems into smaller, more manageable ones that can be easily approached

• individual modules can be worked on by diff ppl

• progress is clearer

• can js test individual modules instead of whole system

• bugs may be isolated to a single module, changes to individual modules reduce risk of impacting the rest of the code

4 control structures

sequence, selection/decision, repetition/looping, subroutines

whats a stub

placeholder for subroutine not written yet so subroutines higher in the chain can be written/tested first

design process approaches

top town, bottom up

what is top down approach

high level definition of problem decomposed into smaller and smaller parts

what is bottom up approach

individual data/operations first considered then composed into bigger constructs

what do structure charts show

hierarchy of subroutine and flow of data between them

structure chart symbols

• rectangle = subroutine

• open circle arrow = data passed between subroutines

• closed circle arrow = boolean passed between subroutines

• circling arrow = repetition/loop

• square = decision

storyboard types

low fidelity and high fidelity

mechatronics definition

practical application of systems that combine software with electronics and mechanics to perform actions

what is a microcontroller

generic computing unit that performs calculations + logic operations

benefits of microcontrollers

small, cheap, use less power, dont have an operating system (preprogrammed for specific task)

components of a microcontroller

microprocessor (CPU), random access memory, flash memory, I/O (pins), clock/oscillator

what is a CPU

controls/monitors all processes, reads + executes logical and mathematical operations

how does a CPU work

has an instruction set consisting of opcodes (machine level commands) that it can execute, higher level languages need to be translated into code made of opcodes that match processors instruction set to work

what is random access memory

temporary storage used while program is running

what is flash memory

permanent, writable memory to store programs

what are I/O ports

inputs/outputs to/from outside world, the pins

what is a clock/oscillator

synchronises operations of CPU

what is a register

fast, temporary storage areas

what are the types of registers

data register and address register

what is a data register

store info used in program

what is an address register

stores addresses of other info in RAM

what is a sensor

provide input from the environment to mechatronic system for processing before producing output, has a transducer that converts energy to electricity

what is a digital sensor

produces discrete values

digital sensor examples

pushbutton switch, Passive infrared sensor, rotary switch

what is an analog sensor

produce continuous values

analog sensor examples

thermistor, photoresistor, ultrasonic sensor

how does a light level sensor work

changes its electrical resistance based on presence of light

what is an actuator

converts electrical signals into physical motion

rotary actuators examples

servo, DC motor, stepper motor

linear actuator examples

rod, selenoid

what are end affectors

one or more actuators used in combination w mechanical linkages and other components to create complex motion (e.g robot gripper)

what is a closed loop system

implements feedback to inform actions so must inc. actuator and a sensor

what is autonomous control

ability of a system to operate independently w/o continuous human intervention

what does autonomous control require

sensors + actuators + intelligent control algorithms to enable machines to perceive environment, make decisions, and execute tasks in real time

types of motion constraints

completely, incompletely, successfully

what is completely constrained motion

part can only move/rotate in a single dimension

what is incompletely constrained motion

a part is able to move in more than one dimension

successfully constrained

load or other imposed feature prevents movement beyond single dimension

what are degrees of freedom

range of motion of a mechatronic system

what are the two ways to describe degrees of freedom

1. final/desired motion of a single part or end affector

2. total controllable motion across all parts of a system

what are the 6 degrees of freedom

translation through x/y/z axes (forwards/backwards, up/down, left/right), rotation around these exes (pitch, yaw, role)

what is an electrical circuit

closed loop/path that forms a network of electrical components where electrons can flow, must be driven by voltage (battery), components draw a certain current