Magnetic sensors are central to how modern industrial systems measure position, speed, current and proximity. Whether tracking the angle of a robotic joint, the rotation of a motor shaft or the flow of current through a power converter, they translate physical movement and electrical activity into signals that control systems can act on. As factories become more connected and automated, the demand for these sensors and for the electronics that interpret them continues to grow.
According to Siemens’ 2025 thought-leadership insight on smart manufacturing, sensors are reshaping industry by enabling “the seamless flow of data between machines, devices and systems, facilitating real-time monitoring, analysis and autonomous decision-making“. Delivering that depends on every sensor producing accurate, stable measurements in real time, even when the surrounding environment works against it.
This guide looks at how magnetic sensors work, where they are used in industrial applications, and how to determine when an ASIC may be the right answer alongside catalogue alternatives. Where precision, integration and long-term supply matter, an ASIC deserves careful evaluation alongside catalogue alternatives.
How magnetic sensors work
A magnetic sensor detects the presence, strength or direction of a magnetic field and converts that information into an electrical signal. In industrial systems, that signal is then conditioned, digitised and passed to a control system, a programmable logic controller (PLC), or a higher-level monitoring platform.
Several physical effects underpin the way magnetic sensors operate. The Hall Effect, discovered by Edwin Hall in 1879, is one of the foundational principles behind industrial magnetic sensing. When a current-carrying conductor is placed in a magnetic field, a measurable voltage develops across the conductor at right angles to both the current and the field. That voltage is proportional to the strength of the field, which is what makes the Hall Effect so useful for sensing position, speed and current.
Magneto-resistive technologies take a different approach. Rather than producing a voltage in response to a field, they change resistance. Anisotropic magneto-resistance (AMR), giant magneto-resistance (GMR) and tunnel magneto-resistance (TMR) all rely on the resistance of certain materials varying with the orientation or strength of a surrounding magnetic field. Each offers different trade-offs between sensitivity, temperature stability, cost and signal range.
Inductive sensors, while not strictly magnetic-field sensors in the same sense, are often grouped with them because they rely on electromagnetic coupling to detect metallic targets. Like magnetic sensors more broadly, they perform well in dirty environments where contamination on or around the sensor would interfere with optical or capacitive alternatives.
Types of magnetic sensors used in industrial settings
Most industrial magnetic sensing is built around a few core technologies, chosen based on the measurement required, the operating environment and the level of precision the application demands.
Hall Effect sensors
Hall Effect devices are widely used across industrial magnetic sensing. They are robust, well understood and produce a clean output that scales linearly with field strength across most of their operating range. Their main weaknesses are temperature drift, offset and a relatively modest sensitivity compared with magneto-resistive alternatives. In industrial systems, they are commonly found in position sensors, rotary encoders, current sensors and proximity switches.
Magneto-resistive sensors (AMR, GMR, TMR)
Magneto-resistive sensors can offer higher sensitivity and accuracy than induction-based devices, with lower noise floors. They can also measure static magnetic fields directly, whereas induction-based technologies need either a changing field or sensor movement to generate a signal. This makes them well-suited to high-resolution position sensing, encoder applications and current measurement in compact assemblies.
Inductive sensors
Inductive sensors detect the presence of metallic targets through electromagnetic coupling. They are widely used in factory automation, proximity detection, and automated industrial processes, particularly where dirt, oil, or non-metallic contamination is present.
Swindon Silicon has partnered with global industrial leaders to provide accurate inductive sensor interfaces for smart factory and machine vision applications, as shown in our sensor interface design examples.
Where magnetic sensors are used in industry
The range of industrial applications for magnetic sensing is broad. The same core technologies serve a wide range of industrial use cases, with implementation shaped by the specific measurement required.
Position and angle sensing
Magnetic sensors are widely used to measure linear and angular position in factory automation. In rotary encoders, magneto-resistive or Hall Effect elements detect the rotation of a magnetised target to produce an absolute or incremental position signal.
Swindon Silicon is partnered with a global automation equipment manufacturer to provide innovative ASICs for their positional encoders used in factory automation applications, where magnetic sensors measure magnetic field strength to provide accurate location information. Across both automotive and industrial settings, our position and motion sensor interface ICs deliver angular and linear measurement accuracy suitable for electric motor commutation, robotic joint position feedback and similar high-precision applications.
Speed and rotational sensing
Where rotational speed matters, magnetic sensors detect the passing of teeth on a target wheel or magnetised features on a rotating shaft. They are widely deployed in motor control, conveyor systems and machinery where closed-loop speed feedback is essential to safe and efficient operation.
Current sensing
Magnetic current sensors measure the field generated around a current-carrying conductor and convert it into a voltage or digital reading. They are widely used in power electronics, motor drives, inverters and energy monitoring systems, and offer the practical advantage of measuring current without breaking the circuit.
Proximity detection and machine safety
Magnetic proximity sensors are well-suited to detecting whether guards are closed, parts are seated correctly, or objects are present in a fixture. In safety-critical contexts such as machine guarding, they form part of the first line of defence against accidents, supporting proactive rather than reactive safety outcomes. As factory environments become more interconnected, this kind of real-time sensing underpins both productivity and worker protection.
Selection criteria for industrial magnetic sensors
Choosing the right magnetic sensor for an industrial application means considering multiple elements. Sensitivity, accuracy, temperature performance, power consumption, packaging, longevity and total system cost all factor in. A few key factors include:
Signal quality in noisy environments
Many industrial magnetic sensors generate signals with amplitudes of only a few millivolts, leaving very little tolerance for interference. In busy industrial settings, electrical noise from motors, switching power supplies, inverters and high-frequency drives can easily couple into these small signals and distort them.
As Ross Turnbull, Director of Business Development at Swindon Silicon Systems, explains,
“When sensors are located far from the control cabinet, long cable runs add further vulnerability by picking up common-mode noise or creating ground loops, both of which can shift or obscure the true measurement before it reaches the electronics that process it.”
In magnetic sensing specifically, this matters because the sensor element itself is often placed close to the source of the interference, near motors, drives or high-current conductors that are part of the very system it is measuring.
Temperature drift and offset
Hall Effect sensors, in particular, are sensitive to temperature, which can shift both their offset and their gain. In an industrial environment where ambient conditions vary widely over the course of a working day, uncorrected drift can mean the difference between a system that maintains calibration over years and one that requires frequent intervention. Compensation can be applied externally with discrete components, or integrated directly into the signal-conditioning electronics.
Long-term reliability and lifecycle
Industrial equipment is often expected to run for 10 to 20 years, sometimes longer. That places real demands on every component in the signal chain, including the sensor and its supporting electronics. Off-the-shelf parts can be vulnerable to supply changes, redesigns and end-of-life announcements over that kind of horizon, all of which can force costly requalification or redesign work downstream.
Integration and system cost
Discrete sensor signal chains involve amplifiers, filters, analogue-to-digital converters and protection circuits, all sitting on a printed circuit board (PCB). Each component adds to the bill of materials (BOM), to PCB area, to assembly complexity, and to the number of potential points of failure. For higher-volume applications, that overhead can become significant.
When an ASIC makes sense
For many applications, a well-specified catalogue sensor IC, paired with appropriate signal conditioning, will meet the requirement. Developing a sensor interface ASIC can be a highly beneficial strategic decision, informed by both the technical demands of the application and the commercial picture over the product lifetime, an area we explore in more detail in our guide to custom IC design for industrial applications.
Several scenarios make that case clear, particularly across the industrial sensing applications where ASICs and system-in-package solutions consistently outperform discrete alternatives.
Where signal integrity is the bottleneck
A sensor interface ASIC takes vulnerable, variable raw signals and converts them into stable, accurate, application-ready outputs. The process begins with precision amplification, where low-noise input stages amplify very small sensor signals without altering their shape. Built-in filtering then removes high-frequency electrical noise. Integrated calibration and compensation address temperature drift, non-linearity and small variations between individual sensors.
High-resolution analogue-to-digital converters then deliver a reliable digital output, designed for the specific sensor type.
In magnetic sensing, all of this matters. Hall Effect and magneto-resistive elements are particularly sensitive to the kind of impairments described above, and integrating the full signal chain on a single piece of silicon, alongside the sensing element where appropriate, removes many of the weakest links in a discrete design.
Where integration and BOM reduction matter
With all signal conditioning, conversion, and diagnostic functions integrated, PCB complexity and component count drop, and every device benefits from the same tightly controlled calibration routines.
For higher-volume industrial products, a reduced BOM, smaller PCB area, and simpler assembly can offset the upfront development investment and improve unit economics over the product’s life.
Where built-in diagnostics support safety and predictive maintenance
In addition to conditioning the signal, sensor interface ASICs can include built-in diagnostics, such as detection of open or short circuits, over-temperature conditions, or signals that fall outside expected ranges. These features support predictive maintenance and help improve system safety, both of which are increasingly central to how industrial systems are specified.
Where longevity and supply resilience are essential
Because an ASIC is developed for long-term use in a specific system, it can offer greater protection against unexpected obsolescence than catalogue alternatives, a topic we’ve covered in our piece on preventing obsolescence using custom ICs. Even so, foundry decisions about process technology can affect any semiconductor over a long enough timeline.
Where end-of-life decisions are unavoidable, Swindon Silicon Systems works with customers through structured support such as last-time buys and process transfers, helping maintain continuity of supply.
Building on the right foundations
Magnetic sensors are a well-established part of the industrial sensing landscape, and they will likely continue to be widely deployed as systems become more connected and more automated.
They are accurate, robust, and well understood, and they translate physical and electrical activity into the signals that smart factories rely on. The question for most engineering teams is not whether to use them, but how to get the best possible performance from them across the lifetime of the product.
In many cases, carefully chosen catalogue components are the right answer. In others, particularly where signal integrity, integration, longevity, or volume economics are decisive, a sensor interface ASIC offers performance and supply benefits beyond what discrete solutions can offer.
Swindon Silicon has been designing ASICs for industrial applications for over four decades, and our engineering teams support customers through every stage of the process, from feasibility and specification through to production and long-term supply.
If you have a magnetic sensing requirement and would like to explore whether an ASIC is the right solution, get in touch to discuss your application.
