Position Sensor – Operations and Applications

A position sensor provides information on the position or movement of an object. With Hall effect components, preparation before soldering may require adjusting the length and shape of the connection pins. The MGA Technologies cutting and bending machine handles this step, preparing components to the geometry required for assembly.

How does a position sensor work?

The position sensor can operate in different ways:

• It delivers a signal that varies according to the position of the object. These signal variations translate the displacement.
• It emits a pulse with each elementary movement. Counting the pulses determines the displacement and the position.
• It provides a signal through a field when there is no mechanical connection between the sensor and the moving object. This can be an electromagnetic field, as with eddy current sensors, an electrostatic field, as with capacitive sensors, or a magnetic induction field, as with magnetoresistive, variable reluctance or Hall effect sensors.

There is a wide variety of position sensors, such as:

• The optical sensor, based on the emission and reception of a light beam.
• The ultrasonic sensor, equipped with a transmitter and a receiver. A wave train is reflected by the object to be detected and returns to the source. The distance of the object is determined from the time the wave train takes to travel back and forth.
• The capacitive sensor, which can detect an object of any kind. When an object is in front of the sensing face of the detector, it changes the capacitive coupling. This change in capacitance starts the oscillator, and an output signal is delivered after shaping.
• The pneumatic sensor, which detects an object at a short distance without contact.
• The mechanical sensor, a contact detector that opens or closes an electrical contact through mechanical action on the moving part of the sensor.
• The inductive (Hall effect) sensor. Several types of sensors coexist in this family, since they all rely on a magnetic phenomenon. The Hall effect sensor is one of them.

The Hall Effect Position Sensor

The Hall effect position sensor is a non-contact detection device that reacts to the presence of a magnetic field. It is used for:

• motor commutation,
• multipole magnet detection,
• speed detection (see our page on the speed sensor),
• position encoding.

The Hall effect position sensor is accurate, small and easy to implement. It can be used in two ways:

• by directly detecting the presence of the magnet,
• or by mounting the Hall probe on a magnet to detect the presence of a part.

When the probes are assembled in integrated circuits, amplified and logic outputs are available, which makes implementation easier, particularly with 3-wire sensors. In the automotive industry, for example, gear lever position sensors are programmed and electrically tested on a dedicated test bench.

Which Parameters Should Be Defined to Prepare a Position Sensor Before Soldering?

How a Hall effect position sensor is prepared depends on its package, its pins and its layout in the assembly. Before choosing a cutting and bending configuration, it is useful to gather:

• The drawing of the component as received, with dimensions and number of pins.
• The geometry after preparation, especially the lengths to keep and the bending angles.
• The tolerances to meet, with separate requirements for cutting and bending.
• The component packaging, the volumes to process and the target production rate.

A drawing before and after forming describes the expected operations precisely. If several part numbers must run on the same station, their differences in dimensions and geometry should also be specified so that the required tooling can be studied.

The Position Sensor Preforming Machine

Position sensors are delivered by manufacturers in rolls or strips and must be cut and formed before being soldered onto electronic modules and circuits. MGA Technologies, based near Lyon, France, offers a cutting and bending machine specifically designed to prepare sensors before soldering. Its typical application is Hall effect components used for position detection: the pins are cut to the specified length and bent to the required orientation. For angular sensors, see also our rotary position sensor preforming tool.

The machine accepts magnetic or non-magnetic components with 3 to 5 legs. It bends from 0° to 90°, with up to three positions. Stated accuracy is ±0.1 mm for cutting and less than 2° for bending. Its tools are modular, scalable and interchangeable, which makes it easy to use.

In the configuration shown, loading and unloading are manual. Interconnection with existing equipment or integration into an automatic machine can also be considered, as in the position sensor assembly lines built by MGA Technologies. To learn more, see our custom inspection, testing and identification machines.

For your position sensor preparation project, send us the component part number and the drawing after forming so we can define your needs. A downloadable brochure is also available with all the details of the machine.