Haptic business
The NECS actuator is an RMA (repulsive magnetic actuator). It delivers input sensing, haptics, and sound by leveraging the magnetic field and repulsive force generated between two magnets with the same polarity facing each other.
By utilizing sensitive changes in the magnetic field, it can produce delicate and diverse tactile feedback and audio.
Enables input sensing, haptics, and sound with a single component
Immediate access to signal input and quantitative measurement data for module and set developers
Technology
Input sensing
A magnetic field is formed between the two magnets in the RMA, and the impedance of the wound coil changes as the distance between the magnets changes. Any change in the distance between the two magnets—whether caused by a human hand, plastic, metal, or any other material—produces an impedance change that can be used as a sensor signal. Touch or pressure sensors used as haptic triggers in electronic devices and other equipment can be replaced by an RMA sensor.
Vibration for haptics and sound output
RMA is an actuator in which two magnets with the same polarity face each other, such as N–N or S–S. A repulsive force acts between the two magnets. Of the two magnets, the input magnet with the coil wound around it is firmly fastened to a fixed base plate, while the output magnet without a coil is attached with a high-temperature adhesive to a base plate capable of haptic and sound output.
When voltage is applied to the bottom magnet (bottom) that has a coil and is firmly attached to the fixed base plate, current flows through the coil. This generates a Lorentz force through the interaction of the electric and magnetic fields, pushing the top magnet (top) away. By varying the magnitude and duration of the input voltage, module or set designers can create a wide range of haptic and audio outputs as desired.
Module
In an RMA, the current flowing through the coil generates a Lorentz force. This force pushes and pulls the magnet attached to the upper plate, which serves as a diaphragm, causing the upper plate to vibrate up and down and generate haptics and sound. In other words, even with the same input signal, the output can vary significantly depending on the material, thickness, and suspension condition of the plate to which the upper magnet is attached. Module designers need to understand these RMA characteristics and design the mechanical structure to optimize haptic and sound effects, while monitoring results as they vary the input signal.
NECS provides Development Kit 1, 2, and 3 to help module engineers design optimal input signals.
Heat generation problem
RMA uses a coil with 150 turns or more, so heat is generated by the current induced by the applied voltage and the coil’s resistance. Module design engineers should therefore apply design measures from the early design stage to maximize heat dissipation. When fastening the bottom magnet with the coil to the base plate, the design should include a sufficiently sized heat-dissipating metal component.
Heat generation mainly occurs in low-frequency ranges where high energy is required. When designing sound effects where low frequencies are not an absolute requirement, applying an HPF can reduce heat generation.
For haptic applications that require low-frequency operation, the design should limit the duration of continuously applied voltage to prevent heat generation issues.
Product
The NECS RMA is classified as active or passive depending on whether it has a sensing function, and it is also classified as circular or square depending on the component shape.
The model name is designated as follows:
Active RMA
Active RMA is a product with a structure that includes a separate coil for detecting impedance changes caused by changes in the distance between the two magnets, in addition to the coil that generates Lorentz force when voltage is applied.
모델명 | 지름(mm) | 두께(mm) | 체적(mm³) | 무게(g) |
|---|---|---|---|---|
AC-090-035 | 9.0 | 3.5 | 223.0 | 1.1 |
AC-120-048 | 12.0 | 4.8 | 543.0 | 3.1 |
AC-160-064 | 16.0 | 6.4 | 1287 | 7.6 |
Passive RMA
Passive RMA is a product with a structure in which a coil for applying voltage is wound around the magnet fastened to the bottom plate, unlike the magnet attached to the top plate.
모델명 | 지름(mm) | 두께(mm) | 체적(mm³) | 무게(g) |
|---|---|---|---|---|
PC-090-035 | 9.0 | 3.5 | 223.0 | 1.1 |
PC-120-048 | 12.0 | 4.8 | 543.0 | 3.1 |
PC-160-064 | 16.0 | 6.4 | 1287 | 7.6 |
PC-250-108 | 25.0 | 10.8 | 5301 | 34 |
Square RMA
NECS provides square products to support more convenient mechanical design of the product to which the RMA is attached. Depending on customer requirements, NECS can provide customized active or passive RMA in various shapes and sizes.
모델명 | 가로(mm) | 세로(mm) | 두께(mm) | 체적(mm³) | 무게(g) |
|---|---|---|---|---|---|
PS-0616-022 | 16.0 | 6.0 | 2.2 | 211.2 | 1.2 |
Development Kit
Various vibration pattern input
RMA is an actuator that can generate various vibration patterns while utilizing the full frequency range, rather than producing only simple vibration patterns in a specific resonance frequency band. To maximize these advantages of RMA, NECS provides Development Kit 1 and Development Kit 2, which allow various signals to be input.
Quantitative measurement of haptic results
One of the difficulties haptic design engineers face is that it is not easy to quantitatively analyze haptic vibration results. The G-force data provided by actuator suppliers represents the G-force value of the actuator itself, not the value in a set state with the actuator installed in a device. Therefore, during development, many haptic design engineers perform qualitative evaluations by relying on the tactile feel delivered to their fingertips from the vibration performance of the set with the actuator installed. For quantitative vibration measurement, there is the inconvenience of having to use expensive vibration measurement equipment. NECS provides its own developer mobile G-force meter at a reasonable price.
Development Kit 1 (D-Kit-1)
Development Kit 1 is designed to make it easy to evaluate the performance of a haptic actuator and to intuitively apply and test it in various environments.
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Signal selection and vibration intensity can be adjusted using touch-based buttons.
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A communication function with the MCU is provided so that users can add WAV or MP3 files they created.
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The MCU can be accessed via a Wi-Fi network, and communication is possible using simple tools such as PuTTY or WinSCP.
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Button settings can be added or changed with simple code modifications.
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In the button setting code, the button title and the linked WAV or MP3 file can be freely edited.
Development Kit 2 (D-Kit-2)
Development Kit 2 is designed to support the development and demonstration of haptic feedback systems using the NECS haptic actuator. The difference from Development Kit 1 is that it provides haptic developers with greater flexibility to input various haptic signals and also allows input sensing conditions to be configured.
Features
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Based on Infineon PSoC™ 4100S Plus + TI DRV2511
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Scilab-based .wav to PWM conversion
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Recognizes actuation sensing functionality
Input sensing
Input sensing is a technology that detects press and release actions on the surface that provides haptic feedback, based on voltage changes generated in the coil that detects the user’s input.
With Development Kit 2, the following parameters can be adjusted.
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Press threshold
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Release threshold
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Release ratio
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Minimum delay
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ADC LSB size
G-force measurement system
The NECS G-force measurement system was developed to support haptic development engineers’ design work. Haptics fundamentally involves vibrating the device to be operated. Haptic development engineers design delicate vibration patterns to provide a better tactile feel, while also designing and testing differentiated vibration modes that represent various situations.
The NECS G-force measurement system is a developer-oriented measurement tool that makes it easy to quantitatively capture and display, as data, the vibrations delivered to a user’s fingertips or other parts of the body by the various input signals designed in this way.
