Sensors Case

Q2:

1) PhotoElectric Sensor:

This sensor comes with an emitter and a receiver in the same housing. It transmits a pulsed infrared or red light beam from the emitter and reflected back by a 'triple prism' reflector. The sensor is switched when the light beam is interrupted by the presence of an object. This device recognizes objects independently of their surface qualities, as long as they are not too shiny.

2) Inductive Proximity Sensor:

This sensor produces electromagnetic field by the coil. If a metallic object approaches the detecting coil, it'll dampen the oscillation around the detecting coil. The change of condition thus causes the output circuit to operate. The metal object to be detected is places within an inch or two from the sensor face.

3) Fiber Optic Sensor:

This sensor comes with an optical fiber cable that transmits light through the core, and the light is then transmitted out from the emitter towards the object and reflected back to the receiver that is located in the same unit with emitter. This device also can show the user the strength of the light reflected back to the receiver. The more luminous the object surface is, the stronger the light received by the receiver. And the closer the object to the sensor, the stronger the signal is.

4) Magnetic field sensor

This sensor consists of two components which are the permanent magnet and the sensor unit. The sensor unit is typically mounted to the wall whereas the permanent magnet is mounted to a movable element like a door or a window. When the door is closed and the alarm is switched on, the matched magnetic field aligns with the reed switch arrays. This closes the switches and makes it a closed circuit. When the door is open or the magnetic field is not properly aligned with their reed switch array, the circuit will break and thereafter triggers the alarm to sound.

5) Micro Switch:

Micro switch is a tough sensor in the form of a switch that is only sensitive to force. This sensor needs a physical contact to change its stage which is either 'ON' or 'OFF'.

6) Pressure sensor:

This sensor is to measure pressure by using the silicon chip inside it. The silicon chip flexes as pressure changes. The amount the silicon chip flexed determines the output voltage signal.

7) Capacitive