The diagram in Fig. 1 shows part of a self-service laundrette. Customers select a wash programme on a touchscreen built into each machine. Inside the washin...
Question 1 Report
The diagram in Fig. 1 shows part of a self-service laundrette. Customers select a wash programme on a touchscreen built into each machine. Inside the washing machine, a controller reads temperature and water-level sensors, then operates a motor, pump and heater. The controller uses software stored in memory to carry out the same sequence for every wash. The owner can change prices using a separate computer but customers cannot install their own software on the machine. The owner wants to explain the difference between this device and a home laptop.
(a) State two input devices shown or described in the laundrette system. [2]
(b) Give three output devices controlled by the washing-machine controller. [3]
(c) Explain why the controller is an embedded system. [4]
Answer Details
(a) Two inputs are the touchscreen and a temperature sensor or water-level sensor. Sensors provide measurements to the controller. [2]
(b) The controller operates the motor, pump and heater. These are outputs because they act on the washing machine’s physical system. [3]
(c) The controller is an embedded system because it is a computer system built into a larger device, the washing machine. It has the specific purpose of running the wash cycle, receives sensor data and automatically controls components. Users cannot use it for unrelated general computing or normally install arbitrary applications. [4]
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