Inductive Proximity sensing

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