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Engineering and Manufacturing

Subject update | 30 March 2022

BTEC Nationals Level 3 in Engineering - Guidance on Unit 6: Microcontroller Systems for Engineers (31725H)

This guidance is to provide an update on the selection of I/O devices for Unit 6: Microcontroller external assessment.

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The Unit 6 specification for the above paper lists a range of input/output (I/O) devices (see topics A2 to A3) that learners need to select and use to build and program a prototype microcontroller system as part of the practical exam. Please note that:

  • Learners should be taught how to use each type of I/O device. For example, to measure temperature there ​are three possible devices that could be used: ​(a) ​thermistor​, (b) temperature sensor​, and​(c) environmental sensor​ ​(temperature and humidity) and we expect learners to have available and be able to use​ (practice with)​ one of ​these types of temperature​ sensor. This means that in this case you do not need to purchase all of the different types of temperature sensor listed​. However, for the 'presence' sensors learners will need to have access to and be able to use most types of device, e.g. to detect the presence of a magnet, a metallic object, a non-metallic object, infra-red radiation and to measure distance.

  • Learners must select their own I/O devices from the range listed in the specification, because credit is gained for selecting and using appropriate devices given the context of the task. In addition, it is often possible to solve a problem in more than one way, so centres must not give learners guidance on which I/O devices to use. Please note that we would never expect learners to have access to and to be able to use an I/O device that is not included in the specification.

  • If a learner does not know how to use and program an appropriate type of I/O device, then they could simulate the specific device using a switch/button. For example, if the learner does not know how to detect the presence of a magnet using a reed switch, then they could simulate the input device using a switch/button, but they will not gain as much credit as a learner who has used an appropriate device.
    Learners are able to access datasheets for the I/O devices listed in the specification during the practical examination.

Please​ ​also​ refer to the SAM, SMLW and Lead Examiner reports on our website to see the types of​ I/O​ devices that are typically ​needed for the live assessment. You will notice that the live papers require far fewer I/O devices to be used than listed in the specification, but over​ the lifetime of the qualification we will cover ​a range of the I/O devices listed in the specification​​.​


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