We are going to break this one into different sections, because there are too many sensors to cover in one post. This time we will look at shock, vibration, tilt and acceleration (including crash sensors).
1. Shock Sensors
How it works: Shock sensors detect physical impact or vibration through a mechanical or electronic sensing mechanism. The most common technology used in shock sensors is piezoelectric, which generates an electrical charge when subjected to force, indicating the magnitude of the shock.
Use case:
- Asset Protection: Shock sensors are often used in theft prevention systems. For example, in freight transportation, if a container is dropped or tampered with, a shock sensor can trigger an alert to notify the sender or receiver that the shipment has been compromised. Similarly, shock sensors in security systems detect intruders breaking into a facility by forcing doors or windows open.
2. Vibration Sensors
How it works: Vibration sensors detect oscillations or movements. The most commonly used type is the accelerometer, which measures the rate of change of velocity. Another form uses a piezoelectric element that generates a voltage when subjected to mechanical stress.
“The piezoelectric vibration activity sensor senses vibration from up and down motion, and the accelerometer senses anterior and posterior motion.”
Science Direct – Accelerometer-based Collision Detection
Use case:
- Condition Monitoring: In industrial applications, vibration sensors are used to monitor the health of machinery. For instance, on large motors or turbines, excessive vibration can indicate wear or an impending failure, and the sensor can alert maintenance teams to take corrective action before breakdowns occur.
3. Tilt Sensors
How it works: Tilt sensors measure the angle of inclination relative to the earth’s surface, typically using an accelerometer or a mercury-based mechanism. When the device tilts beyond a certain threshold, it triggers a signal.
Use case:
- Agriculture: Tilt sensors in agricultural equipment (like irrigation systems or crop-monitoring devices) help ensure proper positioning. If a sensor detects that a piece of equipment has become misaligned, it sends an alert to the system operator.
4. Motion Sensors
How it works: Motion sensors detect movement in their environment using a variety of technologies, such as passive infrared (PIR), ultrasonic, or microwave sensors. PIR sensors detect changes in infrared radiation (heat) emitted by objects, while ultrasonic sensors emit sound waves and measure the time it takes for the waves to bounce back.
Use case:
- Home Automation: Motion sensors in smart homes can trigger actions, like turning on lights or activating security cameras when someone enters a room. In security systems, they are widely used to detect unauthorized movement within a monitored area.
5. Acceleration Sensors:
How It Works: Accelerometers in cars measure the sudden increase in acceleration (or deceleration) during a crash. The sensor uses a small mass suspended on a spring, which shifts in response to acceleration, generating an electrical signal that is processed to detect a collision.
- Use Case: In vehicles, acceleration sensors are often used for collision detection and to trigger airbag deployment. When a rapid deceleration occurs (such as in a crash), the sensor detects the abrupt change in velocity and sends a signal to activate safety mechanisms like airbags or seatbelt tensioners.
