Mikroelektronika d.o.o.
Kappenrad-Klickplatine
Kappenrad-Klickplatine
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Das CAP Wheel Click Board™ ist ein kapazitiver Berührungssensor mit runden Elektroden, die auf einem Click Board™ integriert sind. Dieses Click Board™ kann Berührungen sogar durch Kunststoff, Holz oder andere dielektrische Materialien hindurch wahrnehmen, die zum Schutz der Oberfläche der Leiterplatte und der Sensorpad-Leiterbahn selbst verwendet werden können. Daher wird das CAP Wheel Click Board™ mit einer Auflage aus Plexiglas geliefert. Im Gegensatz zum mechanischen Knopf hält der kapazitive Berührungsknopf viel länger, er ist nicht anfällig für Beschädigungen und Verschleiß im Laufe der Zeit und er ist sehr zuverlässig.
Capacitive sensors are a very popular method of controling various devices. Besides the aforementioned benefits, having a touch sensitive button on a device allows for a compact design, opens possibilities for various kinds of human-machine interface and - it looks good and modern, especially if 8 LEDs array thatthe CAP Wheel Click Board™ has onboard is taken into account. The CAP Wheel Click Board™ can find its place among many applications - for touch activated lighting controls, process control, touch activated control panels, toys and any other applications that need a switch or an encoder.
How Does The CAP Wheel Click Board™ Work?
Although it looks simple at first glance, capacitive touch sensing is not an easy task. There are many parameters that need to be sampled, filtered, compared and processed before positive touch detection and its position are confirmed. To make this possible, Cap Touch click utilizes the IQS333, ProxSense® IC, a 9-channel projected (or 7-channel self) capacitive proximity and touch controller from Azoteq. This IC has some advanced features such as the auto drift compensation, Long proximity range, Automatic adjustment for optimal performance (ATI), two Configurable 11-bit sliders/scroll wheels and more. These features enable the CAP Wheel Click Board™ to exhibit very reliable and accurate touch detection.
Capacitive touch sensing is based on detecting a change in capacitance, due to the influence of a foreign object. Basically, the capacitance of the sensor, also known as the antenna, is measured and monitored and if a significant change occurs, after processing by the detection integrator, a touch event is acknowledged. To maximize performance, many routing requirements need to be met in the sensing electrodes design. The relation between the sensing elements in position and size is crucial. The CAP Wheel Click Board™ is designed with these requirements in mind and electrodes are "Self-Capacitive Wheel" shaped.
The CAP Wheel Click Board™ also contains 8 LEDs whose function can be user-defined. LEDs are connected to PWM LED driver pins on IQS333 which means that the user can turn LEDs on or off and control illumination, using the dimming modes that IQS333 supports.
The IQS333 IC interfaces to a master controller via a 3-wire (SDA, SCL, and RDY) serial interface bus that is I2C™ compatible, with a maximum communication speed of 400kbit/s. The host MCU has the capability to force a communication at any time, by pulling the RDY line low. The communication will start directly following the current conversion cycle. If the event is terminated by the watchdog timer, the device will reset.
After every power on cycle, the device will recalibrate itself. It will take some time, so it should be taken into consideration when building custom applications. MikroElektronika provides libraries and the demo application, that can be used as a reference for any future designs.
As mentioned before, the CAP Wheel Click Board™ is I2C™ compatible and uses SCL, SDA and RDY pins for communication which are routed to SCL, SDA and INT pin on mikroBUS™ respectively. Besides that, CLR pin is available on board which is routed to RST pin on mikroBUS™ and used to master reset the IC.
SPECIFICATIONS
| Type | Capacitive |
| Applications | It can be used for touch activated lighting controls, process control, touch activated control panels, toys and any other applications that need a switch or an encoder. |
| On-board modules | IQS333, ProxSense® IC, a 9-channel projected (or 7-channel self) capacitive proximity and touch controller from Azoteq. |
| Key Features | Auto drift compensation, Long proximity range, Automatic adjustment for optimal performance (ATI), 2 Configurable 11-bit sliders/scroll wheels and more. |
| Interface | GPIO,I2C |
| Compatibility | mikroBUS |
| Click board size | L (57.15 x 25.4 mm) |
| Input Voltage | 3.3V |
PINOUT DIAGRAM
This table shows how the pinout of the CAP Wheel Click Board™ corresponds to the pinout on the mikroBUS™ socket (the latter shown in the two middle columns).
| Notes | Pin |  |
Pin | Notes | |||
|---|---|---|---|---|---|---|---|
| NC | 1 | AN | PWM | 16 | NC | ||
| Master Clear | CLR | 2 | RST | INT | 15 | RDY | Ready Output |
| NC | 3 | CS | RX | 14 | NC | ||
| NC | 4 | SCK | TX | 13 | NC | ||
| NC | 5 | MISO | SCL | 12 | SCL | I2c Clock | |
| NC | 6 | MOSI | SDA | 11 | SDA | I2C Data | |
| Power Supply | +3.3V | 7 | 3.3V | 5V | 10 | NC | |
| Ground | GND | 8 | GND | GND | 9 | GND | Ground |
ONBOARD SETTINGS AND INDICATORS
| Label | Name | Default | Description |
|---|---|---|---|
| LD1-LD8 | - | - | User configurable LED indicator |
| LD9 | PWR | - | Power LED Indicator |
Software Support
We provide a library for the CAP Wheel Click Board™ on our LibStock page, as well as a demo application (example), developed using MikroElektronika compilers. The demo can run on all the main MikroElektronika development boards.
Library Description
Library performs the control of the CAP Wheel Click Board™ and allows to set all necessary configurations which include number of activated channels, threshold values for touch for each channel and for proximity, and etc. Also can read data from capacitance wheel and represent that value on LEDs. For more details check documentation.
Key Functions
uint8_t capwheel_writeReg( uint8_t register_address, uint8_t *dataIn, uint8_t nBytes )- Function writes the determined number of bytes to the register.void capwheel_getData( uint16_t *wheelData )- Function reads data from wheel 1 and stores this value in memory via output parameter.void capwheel_setOutput( uint16_t inputData, uint8_t outputMode )- Function sets output LEDs depending on the input wheel data value in the way which is determined with the ouputMode parameter.
Example Description
The application is composed of three sections :
- System Initialization - Initializes peripherals and pins.
- Application Initialization - Initializes I2C interface, performs the device reset and activates the desired channels (from CH0 to CH9), in this example all channels are activated.
- Application Task - (code snippet) - Checks is sense data ready for reading and if was ready, then reads wheel coordinates and sends these results to the LEDs.
void applicationTask()
{
readyCheck = capwheel_checkDataReady();
if (readyCheck == _CAPWHEEL_DATA_READY)
{
capwheel_getData( &senseData );
capwheel_setOutput( senseData, _CAPWHEEL_LED_BRIGHTNESS_NUMBER );
}
}
The full application code, and ready to use projects can be found on our LibStock page.
Other mikroE Libraries used in the example:
- I2C
Additional Notes and Information
Depending on the development board you are using, you may need a USB UART click, USB UART 2 click or RS232 click to connect to your PC, for development systems with no UART to USB interface available on the board. The terminal available in all MikroElektronika compilers, or any other terminal application of your choice, can be used to read the message.
MIKROSDK
The CAP Wheel Click Board™ is supported with mikroSDK - MikroElektronika Software Development Kit. To ensure proper operation of mikroSDK compliant Click board demo applications, mikroSDK should be downloaded from the LibStock and installed for the compiler you are using.
Kappenrad-Klickplatine
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