Systems Approach to Designing

This section explains Systems Approach to Designing in Design and Technology. In Design and Technology, understanding the systems approach to designing is essential. This approach involves looking at how various components work together to achieve a desired outcome, and it is fundamental to the design and manufacture of electronic products, automated systems, and digital technology. In this revision, we will explore systems, microcontrollers as process devices, programming microcontrollers, and outputs, as well as the purpose of output devices.

Systems

A system is a set of interconnected components that work together to perform a specific function or task. In design, a systems approach helps designers to think of products in terms of input, process, and output. These systems can be physical (like a mechanical system) or digital (like a computer system).

A typical system consists of:

• Inputs: Information or energy put into the system to be processed. In electronics, this could be a sensor detecting light, temperature, or motion.
• Process: The mechanism or control system that processes the input to produce the desired result. This could involve mechanical work or, in electronic systems, a microcontroller processing the input.
• Outputs: The result produced by the system. In the case of a light sensor, the output might be turning on a light or sending a signal to an alarm.

Example of a System:

• Input: A temperature sensor detects a rise in temperature.
• Process: A microcontroller processes the signal from the temperature sensor and compares it to a preset threshold.
• Output: The system activates a fan to cool the area down.

Systems are used in everyday life, from simple devices like a thermostat to complex systems like autonomous vehicles or automated manufacturing lines.

Microcontrollers as Process Devices

Microcontrollers are small, low-cost, programmable devices used to control systems. They are often the "brain" of electronic products, receiving inputs, processing them, and sending outputs based on programmed instructions. Microcontrollers are used in everything from washing machines to smart thermostats, toys, and robotics.

A microcontroller consists of:

• A Central Processing Unit (CPU): This is the core that performs calculations and decision-making.
• Memory: Stores the programme (firmware) and data.
• Input/Output (I/O) Pins: These pins are used to connect sensors, switches, and output devices (e.g., lights or motors) to the microcontroller.
• Clock: Keeps the microcontroller running at a consistent speed, enabling precise timing of operations.

Microcontrollers typically interact with other components through input devices (such as sensors) and output devices (such as LEDs or motors). For example, in a smart doorbell, a microcontroller might receive an input from a camera (detecting motion) and output a video feed or activate a speaker.

Programming Microcontrollers

Programming a microcontroller involves writing code that defines how the microcontroller should behave when receiving input, processing that input, and controlling the outputs. The code is usually written in a high-level programming language such as C or Arduino language and then uploaded to the microcontroller.

Steps involved in programming a microcontroller:

• Define Inputs: Specify what sensors or switches the microcontroller will use to gather information (e.g., a temperature sensor, light sensor, or push button).
• Write Process Logic: The program determines what actions the microcontroller should take based on the inputs. For example, if the temperature exceeds a certain value, turn on a fan.
• Set Outputs: The program specifies what should happen once the microcontroller processes the information. For instance, turning on an LED light, activating a motor, or sending a signal to another device.
• Upload Code: Once the program is written, it is uploaded to the microcontroller using a programming environment (such as the Arduino IDE or MPLAB X for PIC microcontrollers).

A typical example of microcontroller programming is using an Arduino board, where you can write simple programs to control LEDs, motors, sensors, and more. For example, an Arduino could be programmed to turn on a light when a motion sensor is triggered.

Outputs and Purpose of Output Devices

Output devices are components that receive instructions from the microcontroller and perform actions, displaying results or interacting with the physical world. The output of a system can vary depending on the type of system and what the product is designed to do.

Types of Output Devices:

• LEDs (Light Emitting Diodes): These are simple output devices used to display information (e.g., a status light indicating whether a device is powered on or off). LEDs are often used in circuits for visual feedback.
• Motors: Motors are output devices that turn electrical energy into motion. They can be used in robotics, automation, or to drive mechanical components like fans, wheels, or conveyor belts.
• Displays (LCD/LED Screens): Displays are used to show information or data from the system. For example, an LCD screen might display the temperature in a thermostat or the time in a clock.
• Speakers: Output devices that convert electrical signals into sound. They are often used in products like alarms, notifications, or music players.
• Actuators: Actuators are used to move or control a mechanism or system. They often work with motors to control movement or force (e.g., in robotics, actuators can control the arms or legs of a robot).

Purpose of Output Devices:

• Provide Feedback: Output devices are used to give feedback to users or systems. For example, an LED light turning on may indicate that a system is active, or a motor moving could indicate that a process is in motion.
• Display Information: Devices like screens or speakers provide visual or auditory output that communicates system information to the user (e.g., a digital clock shows the time, or a buzzer sounds when a task is complete).
• Control Physical Processes: Output devices like motors or actuators enable the system to control physical actions, such as moving parts in a robotic arm, opening a door, or adjusting the position of a solar panel.

Example: In an automated lighting system:

• Input: A light sensor detects the level of ambient light in the room.
• Process: A microcontroller processes the input and determines if the lights need to be turned on or off.
• Output: The microcontroller activates an LED light if the room is too dark.

Example of Actuators: In a smart thermostat:

• Input: A temperature sensor detects the room's temperature.
• Process: The microcontroller compares the temperature to the desired setting and decides whether to turn the heating on or off.
• Output: A relay connected to the microcontroller activates an actuator that controls the heating system.

A systems approach to designing involves considering how components such as inputs, processes, and outputs interact in a product or system. Microcontrollers play a vital role in processing inputs and controlling outputs, enabling automation and interactivity in devices. The programming of microcontrollers is crucial in determining how a system behaves, and the selection of output devices ensures that the system can communicate with users or control physical processes. By understanding these concepts, designers can create efficient, functional, and user-friendly products that utilise the power of electronics and programming to meet user needs.