Sensors · Feedback · Control Systems · Advantages & Disadvantages
CSZoneCambridge IGCSE Computer Science 0478
What is an Automated System?
Computers Making Decisions
An automated system uses sensors to collect data, processes it, and uses actuators to control a physical system — all without direct human intervention. It operates in a continuous sense → process → act loop.
Examples: central heating thermostat, greenhouse climate control, factory assembly line, autopilot systems
1. Temperature sensor reads current temp (e.g. 18°C) 2. Microprocessor compares to desired temp (25°C) 3. If too low → heater actuator turns ON 4. Sensor reads again → if 25°C → heater turns OFF 5. Cycle repeats continuously (feedback loop)
Feedback: output is used to adjust the next input — keeps the system at the desired state
Systems can monitor multiple sensors simultaneously (temperature, humidity, light)
Advantages & Disadvantages
Evaluating Automated Systems
Advantages: operate 24/7 without breaks; more consistent and precise than humans; safer in hazardous environments; can react faster than humans; reduces labour costs long-term.
Disadvantages: high initial setup and maintenance cost; can malfunction causing significant damage; cannot adapt to genuinely unexpected situations; job losses for human workers.
Exam Practice
Have a go at this question
Cambridge IGCSE 0478 style
Describe how a computer-controlled greenhouse heating system uses feedback. Include details of the sensors, processing, and actuators involved.
4 marks
Temperature sensors measure the greenhouse temperature [1]. The microprocessor compares the reading to the desired temperature set point [1]. If too cold, the actuator (heater/valve) turns on [1]. The temperature is continuously monitored and the heater adjusted accordingly — this feedback loop maintains the correct temperature [1].
Key Takeaways
What to Remember
Automated system: sensors → microprocessor → actuators, without human intervention
Feedback: output measured and fed back as input to maintain the desired state