Magnetic sensing technologies detect changes in magnetic fields to determine position, proximity, or motion. These include reed switches, Hall effect sensors, and even magnetoresistive sensors. They are vital in automation for non-contact position sensing, security systems for door/window status detection, and robotics for movement control.
In this blog, we’ll compare magnetic reed and Hall effect technologies to help you choose the right limit switch for your application.
Basic Working Principles
Here’s an overview of how each switch detects magnetic fields and converts them into electrical signals:
Reed Switch
A reed switch consists of two thin, ferromagnetic metal reeds enclosed in a glass tube filled with inert gas. When a magnetic field is brought near, the reeds become magnetized and attract each other, closing the circuit. As soon as the field is removed, the reeds separate, which opens the circuit. It acts as a simple, passive on/off switch triggered by proximity to a magnet.
Hall Effect Switch
A Hall effect switch is a solid-state device that generates a voltage when exposed to a magnetic field perpendicular to the semiconductor’s current flow. Internal electronics process this voltage to produce a digital or analog output. It also requires a constant power supply and can detect magnetic field presence, strength, and polarity.
Electrical and Mechanical Characteristics
Below are the key electrical and mechanical characteristics of reed and Hall effect switches:
Reed Switch
Magnetic reed switches possess the following characteristics that make them suitable for simple, low-power applications:
Operates without external power: The switch functions passively and does not require a power supply.
Uses mechanical moving contacts: It contains two ferromagnetic reeds that physically move to open or close the circuit when exposed to a magnetic field.
Prone to contact bounce during switching: The mechanical action can cause the contacts to momentarily bounce, creating potentially unstable signals during fast switching applications.
Enclosed in a fragile glass housing: The switch is sealed in a thin glass tube, which can easily break under mechanical stress or vibration.
MagneLink switches overcome this weakness by encasing the Reed switch component within a housing to increase the finished switch’s ruggedness to better perform in tough environments.
Operates reliably in dirty or wet environments: The sealed MagneLink housing used on the finished Reed switch ensures resistance to dust, moisture, ice, and other environmental contaminants.
Switches at relatively slow speeds: Due to the movement of internal parts, the reed switch responds slower than solid-state alternatives when used in fast switching applications.
Provides an easily monitored input signal: With a simple make-or-break operation, the reed switch provides a simple input signal for system monitoring of open or closed states.
Hall Effect Switch
The following characteristics of Hall effect switches make them highly suitable for applications requiring durability in harsh or complex environments:
Detects magnetic field polarity: The Hall effect switch can sense the presence and polarity of a magnetic field, allowing for directional detection.
Supports analog or digital output: Depending on the sensor type, it can provide a continuous analog signal or a binary digital output.
Provides consistent performance over time: With no mechanical components, the switch maintains stable operation and accuracy over long periods.
Operates reliably in dirty or wet environments: The sealed, solid-state design ensures resistance to dust, moisture, and other environmental contaminants.
Integrates easily with microcontrollers: It interfaces directly with digital logic systems, making it suitable for embedded and automation applications.
Common Applications
Here are the common uses of reed switches and Hall effect switches across industries:
Reed Switch
Reed switches are commonly used in simple magnetic sensing tasks such as door and window sensors in security systems and float-level sensors in fluid tanks. They are also found in bicycles and treadmills for speed or position sensing due to their simplicity and low cost. In industrial systems, they serve as a simple, passive limit switch.
Hall Effect Switch
Hall effect switches are used in automotive systems for crankshaft and camshaft position sensing, gear speed sensors, and position detectors. In industrial automation, they serve as non-contact limit switches, encoder components, and proximity sensors. They are also common in consumer electronics, such as detecting laptop lids’ open/closed state or smart cover positioning in tablets.
Looking for a Reliable Limit Switch? MagneLink Has You Covered!
MagneLink offers both Reed and Hall effect switches that deliver high performance and durability across various applications. Whether you need a simple, passive solution or a more polarity sensitive sensor, we have the perfect magnetic switch for your needs.
A normally closed (NC) reed switch has contacts that stay closed without a magnetic field and open when a magnet is near. This allows continuous current flow until a magnetic field interrupts it, making it useful for fail-safe applications. In contrast, a normally open (NO) reed switch has contacts that are open when inactive and close only when exposed to a magnetic field.
In this blog, we’ll discuss the advantages and applications of an NC reed switch.
Advantages of NC Reed Switches
Below are the key advantages of utilizing an NC reed switch to enhance system reliability:
Fail-Safe Operation
NC reed switches remain closed (active) when no magnetic field is present, which makes them ideal for safety-critical systems. This fail-safe feature ensures that the circuit remains intact unless deliberately interrupted by a magnetic field, reducing the risk of accidental failure.
Low Power Consumption
An NC reed switch doesn’t require power to maintain its default closed state, making it highly efficient in battery-powered and low-energy applications. For example, it is commonly used in security systems to detect door or window openings without draining the battery.
Long Mechanical Life
Reed switches are built with sealed glass tubes that contain the switch contacts, preventing physical wear from repeated actuation. Since there is no direct contact or friction during switching, the mechanical life of such switches is extended.
Simple Integration
NC switches can be easily integrated into both digital and analog circuits. Their simple on/off functionality, with minimal wiring and components, allows for easy implementation in various systems, such as alarms and position sensors.
Enhanced Environmental Resistance
The sealed glass housing protects the internal contacts from dust, moisture, and chemical exposure. MagneLink switches take it a step further and enclose the sealed glass reed housing within the switch housing for added protection. This makes them suitable for use in demanding conditions, such as industrial environments, automotive systems, or outdoor devices.
Fast Response Time
NC switches have quick actuation speeds due to their simple mechanical design. This guarantees that they respond rapidly to changes in the magnetic field, making them ideal for applications requiring immediate feedback, like security system triggers.
Industrial Applications of an NC Reed Switch
Here are the common industrial uses of an NC reed switch:
Door and Window Sensors in Security Systems
When a door or window is closed, the reed switch remains closed, and the circuit stays active. If the door or window opens, the magnet is separated, causing the circuit to open and trigger an alarm. This provides an effective and reliable way to monitor unauthorized access to entry points.
Position Detection in Industrial Automation
In industrial automation, NC switches are used for position detection of moving components like robotic arms, actuators, and conveyors. They provide precise feedback for controlling and monitoring the position of machinery by detecting the presence or absence of a magnet.
Automatic Lighting, and Other Functions
With a door closed using a NC switch, lighting remains OFF. When a door is opened with the NC switch, lighting turns on in a room or closet space. This allows for hands free and easy power savings for lighting – or other functions, like fans or refrigeration.
Lid Detection in Laptops and Tablets
Many laptops and tablets use NC switches to detect whether the lid is open or closed. When the lid is closed, the switch remains closed, signaling the device to enter sleep or hibernation mode. This feature enhances user convenience and energy efficiency, especially in portable electronics.
Fluid Level Monitoring in Medical Devices
NC reed switches are used for fluid level monitoring in medical devices like infusion pumps or diagnostic machines. They can detect when the fluid reaches a certain level, which is critical in medical environments for patient safety.
Brake and Clutch Monitoring in Automotive Systems
In automotive systems, an NC reed switch is employed to monitor the engagement of brakes or clutches. It detects the position of the brake or clutch pedal, providing input to the vehicle’s control system to ensure proper operation and safety.
Do you need a reliable, long-lasting solution for your industrial systems? MagneLink’s industrial-grade reed switches offer easy integration and high performance, ensuring safety and reliability in various applications. Our products focus on durability and cost-effectiveness and provide the perfect solution for your needs.
Contact us for high-quality reed switch solutions!
Reed switches are small yet powerful sensors that detect magnetic fields. They operate by opening or closing an electrical circuit in response to the presence of a nearby magnet. When integrated with Arduino boards, reed switches become key components in various applications, offering precise sensing capabilities for tasks ranging from home automation to robotics.
This article explores the integration of reed switches with Arduino, providing insights into how developers can leverage these components for diverse projects. It will also discuss practical examples spanning from home automation to robotics.
Common Uses of Reed Switches With Arduino in Projects
Reed switches are popular with Arduino boards for their simplicity and reliability and are commonly used in various projects. Here are some common utilization and project ideas, demonstrating both simple and complex applications:
Magnetic Door Sensors
Reed switches can detect the opening and closing of doors or windows. A simple security system can be created by placing a magnet on the door and a reed switch on the frame. When the door opens, the magnet moves away from the switch, triggering the Arduino to sound an alarm or send a notification.
Alarm Systems
These reed switches with Arduino offer a simple and cost-effective security solution. Placing a reed switch in a vault with a magnet on the lid allows an Arduino to trigger an alarm or notification when opened. This setup is easy to implement and provides a discreet security measure for valuable equipment.
Odometers
Attaching a magnet to a wheeled vehicle and a reed switch to the frame counts wheel rotations. This enables the calculation of speed and distance traveled. An Arduino can process this data to display real-time stats on an LCD screen.
Model Railways
Reed switches are widely used in model railways to automate functions. Magnets are attached to the train underside trigger, and reed switches are placed along tracks. This setup signals an Arduino to control track changes, signals, or animations, which enhances the realism and interactivity of model railway systems.
Home Automation Systems
These switches are useful in various home automation projects. They can detect the presence of mail in a mailbox, monitor the position of garage doors, or check if household appliances are on or off. These projects often involve integrating reed switches with other sensors and modules to create comprehensive smart home solutions.
Water Level Monitoring Systems
Reed switches can be employed in water level monitoring systems by being placed at different levels in a tank. With magnets attached to floats or markers, the reed switches can detect the rise and fall of water levels. This information can be transmitted to an Arduino for real-time monitoring or to trigger actions such as activating pumps or sending alerts.
Reed Switch Keyboards
These can be used to create custom keyboards. Pressing a key on a keyboard brings a magnet near a reed switch underneath, which closes the circuit. The Arduino can then detect the keystroke and perform the corresponding action, allowing for customizable and durable keyboard solutions.
Robotics Applications
Reed switches with Arduino are perfect for detecting the position of moving parts in robotics and machinery. They can be placed at critical points inside drawers and doors with magnets attached to moving parts. In robotics, reed switches can monitor the position of robotic arms, wheels, or other moving components. This ensures precise control and feedback, allowing the Arduino to adjust movements, maintain alignment, and perform tasks accurately.
HVAC Systems
These switches are useful in heating, ventilation, and air conditioning (HVAC) systems for monitoring air duct dampers. The position of dampers can be detected by placing reed switches at strategic points and attaching magnets to damper blades. This allows an Arduino to adjust airflow dynamically based on temperature or occupancy, optimizing energy efficiency and building comfort levels.
Elevate Your Arduino Experience With MagneLink’s Superior Reed Switches!
MagneLink offers superior reed switches with Arduino, combining quality and customization to meet your needs. Our custom-built magnetic switches ensure you get what you need without overpaying for unnecessary features. Choosing our switches guarantees top-quality, dependable solutions customized to fit your unique applications.
Magnetic reed switches control the flow of electricity in a circuit without requiring an external power source. They are engineered to function through proximity to a magnetic field, so the actuator (the source of the magnetic energy) is simply a magnet paired with a sensor or a switch.
Typically, a reed switch consists of a pair of electrical contacts sited on a magnetic metal reed and enclosed in a protective glass casing. These flexible switches can open and close circuits using AC and DC voltage.
Magnetic reed switches are preferred in many industries because of their wide range of benefits. This article will discuss magnetic reed switches’ common applications and advantages.
Common Applications of Magnetic Reed Switch
Because it is versatile, a magnetic reed switch can be applied to various industries, from home appliances to automotive. Particularly, this magnetic switch can be found in the following battery-operated devices:
Laptops and Mobile Phones
Usually used in clamshell designs and cases, magnetic reed switches allow the screen to turn off when the lid is closed.
Tamper-Proofing Systems
Magnetic reed switches are ideal to use with security systems. They function as proximity sensors that trigger an alarm when the magnet moves away from the switch.
Automobile Doors
As long as a proximity sensor is present, magnetic reed switches can power car doors and the lights connected to refrigerator doors.
Auto Shut-Off Devices
Magnetic reed switches are installed in fluid level sensors and thermal cut-offs in dishwashers, washing machines, and showers.
Measuring Devices
Anemometers used to measure wind speed are operated with magnetic reed switches. They can also power speed sensor devices on bicycle wheels, car gears, and treadmills.
Safety Features in Devices
Magnetic reed switches are a safety feature in devices like food processors and power tools. They help prevent these devices from completely turning on when a lid, guard, or other component is not correctly placed.
Environments With Explosive Gases or Chemicals
Because magnetic reed switches are encased in protective glasses, any sparking from the switching action stays within the casing, preventing accidents in environments with explosive gasses and chemicals.
Benefits of Magnetic Reed Switch
A permanent magnet often powers a magnetic field in a reed switch. However, a current-carrying wire or coil may be used as an alternative. These switches are more cost-efficient than other electrics and consume less power, resulting in low mechanical wear and a longer operational lifespan.
Further, the switches don’t need to be physically accessed to control the electricity in the circuit, reducing the potential for electrical interference. Mechanical reed switches are also durable, reliable, compact, lightweight, and highly customizable in terms of precision and sensibility.
Finally, magnetic reed switches are sustainable and safe to use in hazardous environments because they are enclosed hermetically in glass cases. Hence, they are less vulnerable to corrosion.
Reliable Magnetic Reed Switches at Magnelink
For over 30 years, Magnelink has provided outstanding service and top-notch magnetic switches to clients from diverse industries! Our dedication and extensive experience allows us to supply dependable, innovative, and affordable products to our consumers, such as magnetic reed switches in a broad spectrum of housings:
MLA Housing
MLE Housing
MLF Housing
MLG Housing
MLH Housing
MLL Housing
MLM Housing
MLP Housing
MLQ Housing
MLT Housing
MLU Housing
At Magnelink, we value customer collaboration to deliver various requirements and needs. Contact us to partner with Magnelink! You may also call us at 800-638-0801.
Posted by Maureen VanDyke on | Comments Off on About Reed Sensors
Reed sensors use a magnet or electromagnet to create a magnetic field that opens or closes a reed switch within the sensor. This deceptively simple device reliably controls circuits in a wide range of industrial and commercial goods.
In this article, we’ll discuss how reed sensors operate, the different types available, the differences between Hall Effect Sensors and reed sensors, and the key benefits of reed sensors. We’ll also provide an overview of industries that use reed sensors and how MagneLink can help you create custom reed switches for your next manufacturing project.
How Do Reed Sensors Work?
A reed switch is a pair of electrical contacts that create a closed circuit when they touch and an open circuit when separated. Reed switches form the basis for a reed sensor. Reed sensors have a switch and a magnet that power the opening and closing of the contacts. This system is contained within a hermetically sealed container.
There are three types of reed sensors: normally open reed sensors, normally closed reed sensors, and latching reed sensors. All three types may use either a traditional magnet or an electromagnet, and each relies upon slightly different methods of actuation.
Normally Open Reed Sensors
As the name implies, these reed sensors are in the open (disconnected) position by default. When the magnet in the sensor reaches the reed switch, it turns each of the connections into oppositely charged poles. That new attraction between the two connections forces them together to close the circuit. Devices with normally open reed sensors spend most of their time powered off unless the magnet is purposefully active.
Normally Closed Reed Sensors
Conversely, normally closed reed sensors create closed circuits as their default position. It isn’t until the magnet triggers a specific attraction that the reed switch disconnects and breaks the circuit connection. Electricity flows through a normally closed reed sensor until the magnet forces the two reed switch connectors to share the same magnetic polarity, which forces the two components apart.
Latching Reed Sensors
This reed sensor type includes the functionality of both normally closed and normally open reed sensors. Rather than defaulting to a powered or unpowered state, latching reed sensors stay in their last position until a change is forced upon it. If the electromagnet forces the switch into an open position, the switch will stay open until the electromagnet powers up and makes the circuit close, and vice versa. The operate and release points of the switch create natural hysteresis, which latches the reed in place.
Reed Sensors vs. Hall Effect Sensors
Hall Effect sensors also use the presence of magnetic force to power the opening and closing of a switch, but that’s where their similarities end. These sensors are semiconductor transducers that produce a voltage to activate solid-state switches rather than switches with moving parts. Some other key differences between the two switch types include:
Durability. Hall Effect sensors may need additional packaging to protect them from the environment, whereas reed sensors are protected within hermetically sealed containers. However, since reed sensors use mechanical movement, they are more susceptible to wear and tear.
Electricity demand. Hall Effect switches require a constant flow of current. Reed sensors, on the other hand, only require power to generate a magnetic field intermittently.
Vulnerability to interference. Reed switches can be prone to mechanical shock in certain environments, while Hall Effect switches are not. Hall Effect switches, on the other hand, are more susceptible to electromagnetic interference (EMI).
Frequency range. Hall effect sensors are useable over a wider frequency range, while reed sensors are usually limited to applications with frequencies below 10 kHz.
Cost. Both sensor types are fairly cost-effective, but overall reed sensors are cheaper to produce, which makes Hall Effect sensors somewhat more expensive.
Thermal conditions. Reed sensors perform better in extreme hot or cold temperatures, while Hall Effect sensors tend to experience performance issues at temperature extremes.
Characteristics for Reed Sensors
Reed sensors have many unique characteristics that make them ideal for many different applications. Those characteristics include:
Customizability
Operators can control the conditions and effectiveness of their reed sensors. For example, manufacturers may either mount reed switches on non-ferrous materials or insert a non-ferrous material barrier between the sensor and the mount. At MagneLink, we specialize in adding anti-shock protections, long-lasting mechanisms, and more.
Energy efficiency
Reed sensors only need to be powered when the switch is active in its non-default position. Latching sensors have even more efficient power demands because the switch stays in its last position until actively triggered.
Resistance
Reed sensors resist damage from adverse environmental conditions like moisture, temperature, and extreme weather. This is due to the simplicity of the mechanism, the protective seal, and its sensitivity to the magnetic field regardless of operating conditions.
Safe use in different conditions
Magnetic reed sensors can perform in extreme and hazardous environments. The hermetic seal, resistance to shock, and simplicity of the circuit let it withstand proximity to explosions, vibrations, and other hazards. Reed sensors may also operate safely near explosive gases due to the hermetic seal on the protective container.
Sensitivity
A reed sensor’s sensitivity to the magnetic field stays strong regardless of environmental factors. It will grow more responsive to magnetic fields as the temperature increases.
Applications of Reed Sensors
Reed sensors are heavily used in almost every industry. They provide a very simple and controllable mechanism for safely opening and closing circuits. Industrial facilities typically use one of the various reed sensor types for equipment that passively runs without direct intervention or equipment that automatically powers down in the event of a malfunction.
These default controls, governed by normally open and normally closed switches, create workspaces that are safe and efficient. MagneLink is proud to serve the following industries with high-quality reed sensors:
Appliances. Reed sensors operate well in appliances that create moist or humid environments, such as dishwashers, refrigerators, and washers.
Automation and manufacturing. Reed sensors have countless practical applications in production. Conveyor belts, cylinder pistons, and automated factory machinery all use reed sensors to detect limits and facilitate on/off functionality.
Automotive. Automotive goods need to meet strict standards that protect against failure. Both automotive accessories and OEM parts use reed sensors to create circuits that operate in car engines. These devices need circuitry that can withstand high temperatures, proximity to other circuits (aided by non-ferrous metal barriers), vibration, and gases.
Electronics. Reed sensors facilitate opening and closing of automatic doors. They also serve as proximity contacts for security devices used on doors and windows, or in devices that use a clamshell design.
Extreme conditions. Reed sensors offer reliable performance in applications with extreme temperatures or other harsh conditions.
General Original Equipment Manufacturing (OEM). OEM manufacturers use reed sensors for a myriad of purposes, such as speed sensors for gears and safety switches.
Medical. Electronic medical devices such as pacemakers use reed sensors to provide efficient, reliable circuitry operations with minimal maintenance requirements. Equipment such as defibrillators, sensors, feeding tubes, and hospital beds also implement reed sensors.
Recreational and fitness products. Reed sensors can be used in a variety of recreational and fitness equipment. For example, reed sensors serve as speed sensors in bicycle wheels and treadmills.
Reed Sensors from MagneLink Inc.
MagneLink, Inc. specializes in creating standard and custom reed switches for a variety of industrial and commercial applications. Each sensor comes in several options to best match the applications and intended environment of the sensors. Some of our options for custom switches include:
Housings. We provide a variety of housings that further protect each sensor and allow for easy mounting.
Electrical specifications. Our sensors can be adapted with transformers for use with different switch types and input or output requirements. We also provide different cable and connector types.
Environmental protections. Talk to our engineering team about different protections, such as our anti-shock mechanisms that make reed sensors even more durable.
Accessories. Our accessories include transformers, cables, and connector mate options.
MagneLink has been producing high-quality switches and sensors for more than 25 years. We prioritize customer service and expert custom switch design to produce exactly the right parts for your next project. Contact us today to learn more about our capabilities or request a quote to place your order from our extensive inventory of available switches and accessories.
Posted by Maureen VanDyke on | Comments Off on Magnetic Switch Selection: Reed Switch vs. Hall Effect Switch
Reed switches and Hall Effect switches are both considered magnetic switches since their properties change when exposed to a magnetic field. Strictly speaking, however, Hall Effect switches are transducers since they convert magnetic energy to electrical energy—they can be used as switches with some additional circuitry. Reed switches are true magnetic switches since they close or open in the presence or absence of a magnetic field.
Reed and Hall Effect switches are ubiquitous not only in electronic devices like cell phones and computers, but also in electromechanical systems like automobile control circuits and fluid control systems. System designers weigh many factors before considering Reed switches and Hall Effect switches for an application.
Reed Switches
Reed switches consist of a pair of contacts enclosed in a protective glass casing. The contacts are thin, flexible reeds made of ferromagnetic materials with a small air gap separating their contact points. When there is a strong enough magnetic field parallel to the reeds to magnetize them, they flex and touch to complete a circuit for current flow.
Typically the magnetic field is generated by a permanent magnet, but a current carrying coil of wire may also be used. Unlike Hall Effect switches, Reed switches:
Do not need anything other than the magnetic field to bring about their switching action.
Are not sensitive to the polarity of the magnetic field.
In other words, they will operate the same way for a North-South magnetic field as well as a South-North magnetic field as long as the magnetic field is parallel to the reeds.
The hermetically sealed glass casing of a Reed switch protects it from mechanical shock and environmental factors such as dust, moisture, and corrosive gases. This makes Reed switches ideal for a wide variety of ambient conditions. Applications include:
Reed switches are safe for use in environments with explosive gases or chemicals because any sparking from the switching action stays within the glass case and switch housing encasing the reed switch.
They are widely used as speed sensors in bicycle wheels, car gears, and treadmills.
Reed switches serve as proximity sensors in electronic devices with a clamshell design, detecting whether the device is open or closed—flip phones and laptop computers are examples of such devices.
Applications that feature wide temperature ranges or harmful environmental factors.
Hall Effect Switches
Hall Effect switches are semiconductor transducers that generate an electrical voltage when a magnetic field is present. The generated electrical voltage can be used for activating solid state switches. They require a constant flow of current to make them act as transducers.
When a piece of Hall Effect material carrying an electric current is immersed in a magnetic field that is perpendicular to the current, several millivolts of electric potential develop in the material. The direction of the voltage is perpendicular to both the current and the magnetic field. As such, the polarity and direction of the current and magnetic field are crucial to the proper function of Hall Effect switches.
Unlike Reed switches, Hall Effect switches:
Have no moving parts, so they are unaffected by mechanical shock.
Do not experience wear and tear either despite ‘switching’ at a high rate, even in excess of 100 kHz.
Can be protected from adverse environmental factors like dust and moisture through proper packaging.
For all practical purposes, Hall Effect switches have an infinite life expectancy—with no mechanical components to wear out.
Hall Effect switches are used for a variety of applications, such as:
Measuring the rotational speed of wheels and shafts.
Timing ignitions in internal combustion engines.
Tachometers and anti-lock braking systems.
Limit switches on actuators for automated controlled systems.
Since they respond accurately and quickly to rapidly fluctuating magnetic fields, they are used for sensing the location of magnets in brushless DC motors.
Magnetic Switches from Magnelink
To summarize, both Reed switches and Hall Effect switches are activated by magnetic fields—the former as a classical switch and the latter as a transducer. Reed switches do not need any additional circuitry for switching, while Hall Effect switches do. There are significant differences between the two in sensitivity, switched load capacity, and life expectancy.
Magnelink has been a supplier of reliable, high-quality magnetic switches at affordable prices for over 25 years. We specialize in providing standard and custom switches that meet our customer’s specific needs. Contact us today with your Reed switch vs. Hall Effect switch questions.
