3. Using Sensors to Create Simple Automatic Control
Devices
Concept Explanation:
Sensors are often used in conjunction with controllers and actuators to create
automatic control systems. These systems monitor environmental conditions and
make decisions to control devices based on sensor inputs. For example, a
temperature sensor can be used to automatically turn on a fan when a room gets
too hot.
Creating a Simple Automatic Control System:
- Step 1: Select Sensors: Choose appropriate sensors based on the environmental
parameter you want to monitor (e.g., temperature, light, motion).
- Step 2: Interface with a Controller: Connect the sensors to a microcontroller
or other control unit that can process the sensor data.
- Step 3: Program the Controller: Write a program that reads the sensor data
and makes decisions based on predefined thresholds.
- Step 4: Connect Actuators: Link the controller to actuators, such as motors
or relays, that perform the desired action (e.g., turning on a light,
activating a motor).
- Step 5: Test and Optimize: Test the system to ensure it responds correctly to
sensor inputs and adjust the program as needed.
Example Problem:
Design a simple automatic lighting system that turns on the lights when it gets
dark.
Solution:
1. Sensor Selection: Use a light sensor (photodiode or LDR) to detect ambient
light levels.
2. Controller Interface: Connect the light sensor to a microcontroller, such as
an Arduino.
3. Programming: Write a program that reads the light sensor value. If the light
level drops below a certain threshold, the microcontroller will send a signal
to turn on a relay connected to the lights.
4. Actuator Connection: Connect the relay to the lighting system.
5. Testing: Test the system in varying light conditions and adjust the
threshold as needed to ensure the lights turn on at the desired ambient light
level. | 
