Computer Science · Oct / Nov 2016 · Paper 13 · Question 9
2210
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A security light is controlled by sensors and a microprocessor. Describe how the sensors and microprocessor interact to switch on the security light when an intruder is detected. [6]
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Any six from:
– infrared / motion / pressure (sensor) // sensor detects movement/pressure – signals/data sent (continuously) to microprocessor – converted from analogue to digital (using ADC) – microprocessor compares value with those stored in memory – if sensor value does not match the stored value(s) … – … signal sent to switch on the light – … signal sent to keep the light on – … light remains on for a period of time (30 seconds) – if sensor value matches the stored value(s) … – … light will remain off – … will turn off after period of time (30 seconds) – works in a continues loop [6]
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