HOW DOES IT WORK?

Pressure 16 Click as its foundation uses the WSEN-PADS, a high-resolution, ultra-compact piezoresistive absolute pressure sensor from Würth Elektronik. This MEMS-based absolute pressure sensor includes a sensing element, analog to digital converter, filters, and digital interface that sends the digital pressure data to the host controller. The MEMS-based sensing element consists of piezo-resistors on a thin Si-diaphragm connected in a Wheatstone bridge configuration, which detects absolute pressure in a range of 26 up to 126kPa with selectable output data rate up to 200Hz. This measurement range corresponds to the altitude range from -1877m (below sea level) to 10,109m (above sea level).

The absolute accuracy of the sensor, which is the output deviation from an ideal transfer function over the operating pressure range, is 100Pa that corresponds to approximately 8 meters in altitude. The piezoresistive sensing element of the WSEN-PADS is also sensitive to temperature changes and causes offset errors during pressure measurement. Therefore, real-time temperature compensation of the measured pressure plays an essential role in achieving high accuracy performed with the on-chip temperature sensor.

Pressure 16 Click allows using both I2C and SPI interfaces with a maximum frequency of 100kHz in Standard and 400kHz in Fast mode for I2C and 8MHz for SPI communication. The selection can be made by positioning SMD jumpers labeled as COMM SEL to an appropriate position. Note that all the jumpers' positions must be on the same side, or the Click board™ may become unresponsive. While the I2C interface is selected, the WSEN-PADS allows the choice of the least significant bit (LSB) of its I2C slave address using the SMD jumper labeled as ADDR SEL.

Also, the WSEN-PADS features an interrupt signal routed on the INT pin of the mikroBUS™ socket, which indicates when a new set of measured pressure data are available, simplifying data synchronization in the digital system that uses the device.

This Click board™ can be operated only with a 3.3V logic voltage level. The board must perform appropriate logic voltage level conversion before use with MCUs with different logic levels. However, the Click board™ comes equipped with a library containing functions and an example code that can be used, as a reference, for further development.