Full marks6/6
An embedded system is a computer system that forms part of a larger device and performs a single, dedicated task. In the tracker it is built around a microcontroller, which has the processor, RAM and ROM on one chip, and its program is stored in ROM so it runs as soon as the tracker is switched on. The embedded system monitors the heart rate using a sensor and processes the readings before showing them on the screen. Another function counts the steps using an accelerometer and uses that count to work out the distance walked and the calories burned, and further functions monitor movement at night to track sleep and send the data to a smartphone by Bluetooth. The embedded system also controls the touch screen and manages the battery so that charging stops when it is full and power is saved when the tracker is idle. An embedded system is suitable because it has low power consumption, so the battery lasts longer between charges, which matters for a device that is worn all day and cannot be charged constantly. It is also small and light, so it fits into a wristband, and because it is dedicated to a few tasks it does not need a full operating system, so it is reliable and can be optimised to respond quickly to its sensors. Keeping the cost low also makes the tracker affordable for the customer.
Why: Comprehensive definition including the microcontroller and ROM (AO1), a range of functions each applied to the tracker (heart rate, steps, sleep, Bluetooth, touch screen, battery), and suitability points developed with reasons (low power for a device worn all day, small size for a wristband, dedicated design for reliability and quick response). Sustained lines of reasoning, all three bullets covered: Level 3 (5-6) clearly met.
Some marks2/6
An embedded system is a small computer inside a device. In a fitness tracker it can monitor your heart rate and count your steps. It is suitable because it is small and does not use much power.
Why: Basic independent points only: a basic definition, two functions and one basic suitability point, with no development and almost no application to the tracker (no explanation of why small size or low power matter). Level 1 (1-2 marks), upper end because there are several independent correct points, but no linkage or reasoning for Level 2.
No marks0/6
An embedded system is a computer that you can install apps on. The fitness tracker uses it to play music and send texts. It is suitable because it is like a phone.
Why: The definition is the opposite of an embedded system (it cannot install new software), the functions are ones the tracker does not perform and 'it is like a phone' is not a suitability point. No rewardable content: Level 0 (0 marks).