The Systems Approach: Inputs, Processes and Outputs
How designers plan electronic systems as three blocks: an input that senses a change, a process that decides what to do, and an output that acts, such as a light or a buzzer.
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Input, process, output
Many electronic products can be understood as a system with three blocks. An input senses a change, such as light or heat. A process, usually a microcontroller, decides what to do with that signal. An output then acts in a way the user notices, such as a lamp or a buzzer. Breaking a product into these blocks makes it easier to design.
Input, process, output terms
Learn these four terms before you study the systems approach.
Input or output?
The clearest way to learn the systems approach is to sort devices into inputs and outputs.
Sort every part of the product
Exam questions give a product and ask you to sort each part into input, process or output. Remember the input senses, the process decides and the output acts. The process is nearly always a microcontroller programmed as a counter, a timer or to make a decision.
Match the block
- input
- process
- output
- sensor
- the part that senses a change
- the part that decides what to do
- the part that acts in a way the user notices
- an input device that detects a condition like light or heat
Match the device
- a light sensor
- a switch
- a buzzer
- a lamp
- an input that detects how bright it is
- an input that is turned on by a user
- an output that makes a sound
- an output that gives light
What does the process do?
What does the process block do in a system?
- It decides what to do with the input signal, often using a microcontroller.
- It detects a change in the surroundings.
- It makes a sound or light for the user.
- It supplies the power to the whole system.
Spot the inputs
Select the TWO input devices.
- A light sensor.
- A switch.
- A buzzer.
- A lamp.
Order the signal flow
Put the flow of a signal through a system in order, earliest first.
- A sensor detects a change
- The input signal reaches the microcontroller
- The process decides what to do
- The output device acts
Summarise the system
A system has three parts: input, _____ and output. The input block detects a change using a _____. The process block, often a _____, decides what to do. The output block then acts, such as a lamp giving _____ or a buzzer making a _____.
Count the blocks
A system is split into how many main blocks: input, process and output?
Find the outputs
Tap the TWO output devices.
- Buzzer
- Light sensor
- Lamp
- Switch
- Temperature sensor
Input, process or output?
Decide which block each part of a system belongs to.
- A temperature sensor that detects how hot a room is
- A microcontroller programmed to decide when to switch a fan on
- A buzzer that sounds an alarm
Describe a system
A security light turns on when it gets dark and someone moves nearby. Describe this product as an input, process and output system.
- Name the input device or devices
- Name the process and what it decides
- Name the output device