Two suitable sensors for this task are:

• Soil Moisture Sensor: This sensor works by measuring the volumetric water content of the soil. It typically uses a resistor or capacitive sensor that changes its electrical resistance or capacitance depending on the amount of moisture present. Higher moisture content leads to lower resistance/higher capacitance. This is appropriate because it directly measures the condition of the soil – whether it is dry or not. A low reading indicates dry soil, triggering the watering system.
• Temperature Sensor: While not a direct measure of soil moisture, a temperature sensor can be used in conjunction with a soil moisture sensor. Soil temperature can provide an indirect indication of dryness. Dry soil tends to be cooler than moist soil. The temperature sensor works by measuring the electrical resistance or voltage change caused by temperature variations. This is appropriate as it can help to avoid watering when the soil is cool (e.g., after a recent rain) and potentially prevent root rot. The system could be programmed to only water if the soil moisture is below a certain threshold *and* the soil temperature is above a certain threshold.

An input device is a device that allows data to be entered into a computer system. It converts real-world information into a format that the computer can understand (binary code). An output device is a device that receives data from a computer system and presents it to the user in a human-readable or usable format.

Examples:

• Input Device: Keyboard: The keyboard works by having keys that, when pressed, activate electrical circuits. These circuits send signals to the computer, which translates these signals into characters and commands.
• Input Device: Mouse: The mouse detects movement across a surface (using optical or mechanical sensors). This movement is translated into signals that the computer interprets as cursor movement on the screen.
• Output Device: Monitor: A monitor displays visual information by receiving signals from the computer and illuminating pixels (tiny dots of light) in specific colours and intensities.
• Output Device: Speaker: A speaker converts electrical signals into sound waves. The electrical signal varies the voltage applied to a coil of wire, which creates vibrations that produce sound.

Here are three different types of input devices and their purposes:

• Keyboard: The keyboard is primarily used for entering text and characters into a computer system. It allows users to create documents, code, and input commands.
• Mouse: The mouse is a pointing device used to control a cursor on the screen. It's used for selecting items, navigating menus, and interacting with graphical user interfaces (GUIs).
• Microphone: A microphone is used to input audio signals into a computer. This can be used for recording voice notes, participating in video calls, or creating audio content.