Home learning focus

Learn the basics of microcontrollers.

This lesson includes:

  • two video clips demonstrating inputs, processes and outputs and microcontrollers as process devices

  • two activities to try at home


Every electronic device around your house will be running on an input, process and output design model.

Input devices take a signal from the physical or ‘real world’ and turn it into an electronic signal that a process device, such as a microcontroller, can understand and act upon.

Examples of real-world signals include light level, temperature and pressure, whereas examples of electronic signals include voltage and current.

Input devices are usually either switches or sensors. Switches allow current to flow through them when the contacts inside are joined together, whereas sensors can be used to detect changes in light level, temperature and pressure.

Process devices take the signal from the input stage of a system and act on it by changing it in some way, eg introducing a time delay, counting the number of times something happens or making decisions.

Output devices take the signal from the process device of a system and turn it back into a physical or ‘real-world’ signal, such as light or sound. Light can be created using lamps and sound can be produced using buzzers or speakers.

In the following video, Zoe Dobell talks about inputs, processes and outputs in the context of trains, stations and ticket barriers.

Inputs, outputs and processes in systems used by designers.

Microcontrollers are an example of a process device.

They are computer chips that are used instead of a central processing unit (CPU). They contain a processor, memory and input and output connection pins and provide functionality and give intelligence to products and systems.

Many everyday products are controlled by these devices, such as mobile phones and washing machines - they can be programmed to perform many different processing functions.

Microcontrollers come in different sizes with varying numbers of pins for the connection of input and output devices, eg 8 pin, 14 pin and 18 pin.

In order for microcontrollers to work correctly they must be programmed, which can be done using a range of different methods, including:

  • text-based programming languages, such as BASIC, C++ and Python
  • block-based programming editors,
  • flowchart software
Processors and the microcontroller in the micro:bit.

There are advantages and disadvantages to using microcontrollers.

The size of a circuit can be significantly reduced as programming replaces physical componentsThey often cost more than traditional integrated circuits
They can be reprogrammed many times allowing changes to be made without replacing componentsProgramming software and hardware is required and can be expensive to buy
They have pins for connecting several input and output devices, adding to flexibilityThe language of the system must be learned and this adds to training costs


Now you can try and put some of what you have learned about inputs, processes, outputs and microcontrollers as process devices into action.

Activity 1

Draw a flowchart for the process of washing your hands.

You will need to make sure that:

  • The user washes their hands for 20 seconds
  • They check that their hands are clean

The below worksheet outlines the different flowchart symbols and their functions and can be used for reference.

You will only need a pen and paper.

Activity 1

Activity 2

Use the micro:bit block-based editor to code this hand washing process.

You can start a new project within the editor, and there are many helpful tutorials on the website to help you get started.

You don't need a micro:bit to do this activity as you can create programmes within the online editor without one.

Activity 2

Where next?

Continue your learning with these links:

BBC Bitesize - Design and Technology - Systems approach to designing

There's more to learn

Have a look at these other resources around the BBC and the web.

More lessons for Year 8 and S2
Secondary Design and Technology
BBC Teach Design and Technology