6. Automated systems and robotics

A microcontroller is a complete computer system on a single chip: it contains a processor, a small amount of RAM and ROM, and input/output (I/O) ports to connect sensors and actuators.

It is cheap, small and uses little power, so it is used to control devices such as washing machines and toys. (Compare a microprocessor, which is only the CPU and needs separate memory and I/O.)

A sensor is an input device that detects changes in the physical environment and measures a physical property.

Most sensors produce an analogue signal, but a microcontroller can only process digital data, so an analogue-to-digital converter (ADC) converts the analogue signal into digital data.

An embedded system is a computer system built into a larger device to perform a dedicated (specific) function, usually based on a microcontroller.

Characteristics: does one task; small and compact; low power; cheap to make in large numbers; programmed once in ROM/firmware and usually not changed by the user; often real-time and reliable; limited or no user interface.

Where they are used: washing machines, microwave ovens, fridges, central heating and security systems, cars (engine management, ABS brakes, airbags), traffic lights, digital cameras, smart watches, vending machines, medical equipment.

An actuator is a device that does an action in response to the output from a microcontroller — it turns an electrical signal into physical movement or another physical change.

Examples: motors (open a window, move a barrier), pumps (water plants), valves (open/close a pipe), heaters, buzzers, lights.

Example — automatic greenhouse watering:

1. A moisture sensor measures the soil moisture continuously.
2. The ADC converts the analogue reading to digital.
3. The microcontroller compares the reading with a stored preset value.
4. If the moisture is below the preset value, it sends a signal to the actuator to switch the pump on; if at or above, the pump is switched off.
5. The system loops, so it keeps checking — the new reading shows the effect of the action (feedback).

The same control logic in Python:

PRESET = 40   # % moisture

def control(reading: int) -> str:
    return 'pump ON' if reading < PRESET else 'pump OFF'

for reading in (55, 41, 38, 45):
    print(reading, control(reading))

• Employment: some jobs are lost (repetitive or manual work), but new jobs are created in designing, programming, installing and maintaining the systems; workers may need retraining.
• Safety: systems can do dangerous jobs and react faster than humans, reducing accidents — but a malfunction, sensor fault or cyberattack can cause harm, so systems must be tested and monitored.
• Environmental sustainability: automation can save energy and resources (heating only when needed, precise watering and fertiliser, efficient routes), but making the devices uses materials and energy, they use electricity, and old devices add to e-waste.

Robotics is a branch of technology that deals with the design, construction, operation and use of robots.

• A mechanical structure or framework — the physical body (arms, joints, wheels, grippers) designed for the robot's task.
• Electronic components — sensors to detect the environment, a microcontroller to process data and make decisions, networking hardware to communicate, motors and actuators to move, and a power supply (battery or mains).
• Programmability — it is controlled by a program that can be written or changed so the robot can do different tasks.

Some robots work alone (autonomous), others are controlled by people remotely.

• Employment: manual, repetitive jobs are lost; new skilled jobs are created in designing, programming and maintaining robots; workers need retraining; some work becomes deskilled.
• Safety: robots take over dangerous tasks, so fewer people are injured — but people working near robots can be hurt if a robot malfunctions, so safety guards and sensors are needed; software errors or hacking can be dangerous.
• Environmental sustainability: precise work wastes less material, energy and chemicals (e.g. targeted crop spraying), but building robots uses raw materials and energy, running them uses electricity, and disposal adds e-waste.