Inductive Proximity sensing is more than an application of electric field but it's a tool that's used in many and many applications including airbags in cars, wind turbines, mobile phones, minesweeping robots and many many others . they are very simple in idea but very efficient in applications

1. Inductive
Proximity
sensors
BY
AHMED MAHMOUD AHMED

2. Components
 An inductive proximity sensor has four elements:
 Coil
 Oscillator
 creates a radio frequency field that is shaped and defined by the coil and core
 Trigger circuit
 rectifies the AC sine wave signal to DC
 Output
 It changes according to the presence and absence of the target

3. Basic operation
 Proximity sensors are one type of pre-touch sensors.
 Inductive proximity sensors operate under the electrical principle
of inductance where a fluctuating current, which by definition has
a magnetic component, induces an electromotive force (emf) in a
target object.

4. Basic operation
 When a conducting object is found in sensor’s domain it reduces
the induced current in the electrodes.
 This change in the electric field is detected by the sensors.
 Specialized algorithms process the data and instruct the rest of the
machine to take appropriate action

5. Example from Intel
Robotic hand
 The researchers have incorporated the sensors into a robotic
hand as well, allowing mechanical fingers to adjust to the
size and shape of an object that they encounter.
 The goal, is to improve the ability of robots to grasp objects
in unstructured human environments.

6. The video

7. Wind turbines
 Wind Turbines uses proximity sensors
to determine the best direction to
which it should be adjusted to get
maximum wind possible

8. Advantages
 They are very accurate compared to other technologies
 Have high switching rate
 Can work in harsh environmental condition

9. Minesweeper
 A robot to sweep over an object and collect EF information from it.
 The algorithm then compares, in near real time, this data to a series of
prerecorded signals that describe various shapes, sizes, and orientations
of the object.
 When the algorithm finds a reasonably certain match, it adjusts the
robotic fingers so that they can grasp the object.

10. Disadvantages
 It can detect only metallic targets
 Operating range may be limited