Cypress Sensing Technologies | Cypress Semiconductor
Cypress Sensing Technologies
Cypress' cutting-edge sensing technologies has enabled Cypress to be the market leader in capacitive- and inductive-sensing applications. With industry-leading CapSense® capacitive-sensing and MagSense™ inductive-sensing, Cypress provides sensing solutions that "Just Work" and deliver the robustness and intelligence that consumer, industrial, automotive, and Internet of Things (IoT) applications demand.
CapSense capacitive-sensing can be used for applications that require touch buttons, sliders, wheels, trackpads, and touchscreens. It provides advanced features such as proximity sensing, hover and glove touch, liquid tolerance, and liquid-level sensing. In addition, CapSense provides an intelligent SmartSense® algorithm that compensates for environmental and manufacturing variations.
MagSense inductive-sensing can be used in applications that require metal detection. Applications that require detection through high-quality metal overlays, water-proofing, rotary and linear encoder functionality, and proximity sensing can be designed using MagSense.
Capacitive-sensing vs. Inductive-sensing
| Capacitive-sensing | Inductive-sensing | |
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| Disadvantages |
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CapSense Capacitive-Sensing
CapSense capacitive touch sensing technology measure changes in the capacitance between a plate (the sensor) and its environment to detect the presence of a finger on or near a touch surface.
Capacitive Touch Sensor
A typical capacitive sensor consists of a copper pad of proper dimensions etched on the surface of a PCB, where a nonconductive overlay serves as the touch surface for the button.
Self-capacitive sensing
In a self-capacitance sensing system, the GPIO pin is connected to a sensor pad by traces and vias. Typically, a GND hatch surrounds the sensor pad to isolate it from other sensors and traces.
When a finger is present on the overlay, the conductive nature and large mass of the human body forms a grounded, conductive plane parallel to the sensor pad, where a parallel plate capacitor is formed. The capacitance between the sensor pad and the finger is: 
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CF is the finger capacitance. The parasitic capacitance (CP) and finger capacitance (CF) are parallel to each other because both represent the capacitance between the sensor pin and GND. Therefore, the total capacitance CS is the sum of CP and CF. PSoC converts the capacitance CS into equivalent digital counts called raw counts. Because a finger touch increases the total capacitance of the sensor pin, an increase in the raw counts indicates a finger touch.
Parasitic Capacitance
Finger Capacitance
Top and Side View
Cm with Finger Touch
Mutual-capacitive sensing
Mutual-capacitance measures the capacitance between two electrodes, the transmit (Tx) and receive (Rx) electrodes. In a mutual-capacitive sensing system, a digital voltage signal switching between a VDDIO or VDDD (if VDDIO is not supported in the device) and GND is applied to the Tx pin and the amount of charge received on the Rx pin is measured. The amount of charge received on the Rx electrodes is directly proportional to the mutual capacitance (CM) between the two electrodes.
When a finger is placed between the Tx and Rx electrodes, the CM decreases. Because of the reduction in CM. the charge received on the Rx electrodes also decreases. The capacitive-sensing system measure the amount of charge received on the Rx electrode to detect a touch/no touch condition.
| Products | CapSense Capacitive-Sensing | Product Selector Guide (PSG) |
|---|---|---|
| PSoC 6 Microncontroller |  |
PSoC 6 MCU PSG |
| PSoC 4 Microncontroller | |
PSoC 4 MCU PSG |
| PSoC 5 Microncontroller | |
PSoC 5 MCU PSG |
| PSoC 3 Microncontroller | |
PSoC 3 MCU PSG |
| PSoC 1 Microncontroller | |
PSoC 1 MCU PSG |
| CapSense MBR3 | |
CapSense MBR3 PSG |
MagSense Inductive-Sensing
MagSense inductive-sensing is a low-cost, robust solution that seamlessly integrates with existing user interfaces, and is also used to detect the presence of metallic or conductive objects.
Inductive-sensing works on the principle of electromagnetic coupling between a sensor coil and the metal target to be detected. When the metal target enters the electromagnetic field induced by a sensor coil, some of the electromagnetic energy is transferred into the metal target, as shown in the figure below.
Field Coupling Between Sensor and Metal Target
This transferred energy causes a circulating electrical current called an eddy current. The eddy current flowing in the metal target induces reverse electromagnetic field on the sensor coil, which results in a reduction of the effective inductance of the sensor coil.
The sensor coil is placed in parallel with a capacitor. The parallel combination of sensor inductance and the external capacitor is called a tank circuit. The reduction in the sensor coil inductance causes an upward shift in the resonant frequency of the tank circuit, where this shift in frequency changes the amplitude of the signal across the sensor coil. The change in the amplitude of the sensor coil signal is measured by the PSoC MCU to detect the presence of the metal target in the proximity-sensing distance.
| Products | MagSense Inductive-Sensing | Product Selector Guide (PSG) |
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| PSoC 4700 Microcontroller | |
PSoC 4700 MCU PSG |
PSoC MCUs: CapSense Capacitive-Sensing Documentation
CapSense MBR3 Controllers: Capacitive-Sensing Documentation
| Document Type | Title |
|---|---|
| Datasheets | CapSense MBR3 Device Datasheet |
| Application Notes | CY8CMBR3xxx CapSense Design Guide |
| Technical Reference Manuals | CapSense MBR3 Register Technical Reference Manual |
| Programming Specifications | CapSense MBR3 Third Party Programming Specification |
PSoC MCUs: MagSense Inductive-Sensing Documentation
| Document Type | Title |
|---|---|
| Datasheets | PSoC 4700 MCU Datasheet |
| Application Notes | AN219207 - Inductive Sensing Design Guide |
| AN79953 - Getting Started with PSoC 4 | |
| AN88619 - PSoC 4 Hardware Design Considerations | |
| AN86233 - PSoC 4 Low-Power Modes and Power Reduction Techniques | |
| Technical Reference Manuals | PSoC 4700 Technical Reference Manual |
| Programming Specifications | PSoC 4 MCU Programming Specification |
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Design and Development Tools for CapSense and MagSense PSoC Creator is an Integrated Design Environment (IDE) that enables concurrent hardware and firmware editing, compiling and debugging of PSoC 3, PSoC 4,and PSoC 5 MCUs. Applications are created using schematic capture and over 150 pre-certified, production-ready peripheral Components.  ModusToolbox Software Suite simplifies development for IoT designers. It delivers easy-to-use tools and a familiar microcontroller (MCU) integrated development environment (IDE) for Windows®, macOS®, and Linux®. It provides a sophisticated environment for MCU system setup, wireless connectivity libraries, power analysis, application-specific configurators for Bluetooth® Low Energy (BLE), CapSense®, as well as other peripherals. In addition, code examples, documentation, technical support and community forums are available to help your IoT development process along. It provides support for PSoC 6 MCUs and wireless connectivity devices.  EZ-Click 2.0 is a simple yet powerful software tool that enables development of CapSense® MBR3 solutions. This lightweight Windows® GUI-based tool has been improved to make development of capacitive user-interfaces extremely simple and quick. The tool allows you to setup sensor configuration, apply global system properties, monitor real-time sensor output, and run production-line system diagnostics – all in an intuitive, visually-driven tool, with absolutely no firmware development required!  |
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All PSoC 4 MCU KitsAll PSoC 6 MCU Kits |
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CapSense Capacitive-Sensing for an Induction Cooktop
PSoC MCUs add CapSense’s robustness and intelligence to an induction cooktop’s user interface. In addition, it integrates multiple external analog and digital peripherals within the induction cooktop, with the flexible digital and analog resources provided with the PSoC MCU architecture.
PSoC MCUs provide:
- CapSense capacitive-sensing for buttons, sliders, and proximity sensing for the User Interface (UI)
- Analog peripherals to design custom Analog-Front-Ends (AFEs) to interface to various sensors
- Digital peripherals to drive the cooktop coils, buzzer, and cooling fans
- Segment LCD drivers to run a segment LCD
MagSense Inductive-Sensing for a Washing Machine
PSoC 4700 MCUs enable door position detection of the washing machine lid and rotary encoder functionality with MagSense. In addition, it can integrate simple system peripherals using the flexible analog and digital resources provided in the flexible PSoC 4700 MCU architecture.
PSoC 4700 MCUs provide:
- CapSense capacitive-sensing for buttons, sliders, and proximity sensing for the UI
- MagSense inductive-sensing for door position detection of the washing machine lid and rotary encoder functionality for the dials on the washing machine
- Digital peripherals to drive LEDs and buzzers
- Analog peripherals to design customer AFEs to interface with various sensors