Skip to 0 minutes and 3 secondsMost of the input devices we've discussed so far-- the keyboard, the mouse, the microphone-- are human controlled. The original input, the information, is coming from you. Another type of input device is a sensor. Let's take a look at some of the examples of sensors we use every day here at the Raspberry Pi foundation-- automatic doors, keycard panels, motion sensors for the alarms, PIR lights, smoke detectors, even the milk level in the coffee machine. A great classroom activity is to ask students to design their smart home of the future. Ask them to label inputs, sensors, outputs, and describe how they would interact through automation.

Skip to 0 minutes and 50 secondsGet them to think about the advantages of automation in their smart home and discuss any disadvantages they can think of too. Share your thoughts on any potential classroom activities in the comments below.

Sensors

Most of the input devices we’ve looked at so far are human controlled - the keyboard, the mouse, the microphone. The original input, the information, is coming from you. Another type of input device is a sensor. The input for a sensor is whatever it is they are sensing. Think of the sensor for a security light. It is sensing movement to determine whether or not to turn the light on.

The output is the security light.

The input is the security light sensor

This is a nice example of an automated computer system - the computer sensed an input and delivered an output. Obviously the system was setup by a human but it runs with no human interaction. A lot of computer systems are automated. Can you think of another example? What are the advantages and disadvantages of automation

When talking about automation it’s a good idea to show an example of industry automation. Try to find a video of a factory that makes something with automated machines. Point out the number (or lack of) people in the video. Discuss how long it would take humans to complete the task without automated machines and sensors.

Here’s a video of a mini being made in Oxford:

This is an additional video, hosted on YouTube.

What other automated computer systems that use sensors can you think of?

A thermostat in your house is another example of a system that uses a sensor. It is sensing the temperature in your house to determine when to tell the heating to turn on/off. This system is not just automated though, as you can adjust the temperature at which the heating will switch on or off. Your heating system may also have several other inputs, often on a separate control panel. You can manually set the heating to be on/off, or restrict the times of day that the thermostat is able to turn on the heating.

Whatever the sensor is, it needs to be connected to the system. Lots of automated systems use proprietary connections, while others will run on GPIO pins like those on a Raspberry Pi. Other systems use standard connectors like USB. Increasingly, sensors use wireless connections using Wi-Fi or Bluetooth. Each connection comes with advantages and disadvantages. For example, the ease of use, the need for specific drivers, or reliability of wireless signals

A nice lesson activity is to ask students to design the smart home of the future. Using input devices, sensors, output devices, and describing how they interact through automation. Ask them to label each device and describe what automation is. Discuss the advantages and disadvantages automation gives to their smart home. Students really enjoy using their imagination when it comes to designing a home with the latest technology.

There are some Raspberry Pi projects available where you can program sensors using Python:

Have you tried creating an automated system in the classroom? How did it go? What advice do you have for others on which projects work best? Share your ideas in the comments below.

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This video is from the free online course:

Understanding Computer Systems

Raspberry Pi Foundation