VAV Press Click is a compact add-on board that contains a board-mount pressure sensor. This board features the LMIS025B, a low differential pressure sensor from First Sensor (part of TE Connectivity). It is based on thermal flow measurement of gas through a micro-flow channel integrated within the sensor chip. The innovative LMI technology features superior sensitivity, especially for ultra-low pressures ranging from 0 to 25Pa. The extremely low gas flow through the sensor ensures high immunity to dust contamination, humidity, and long tubing compared to other flow-based pressure sensors. This Click board™ is suitable for pressure measurements in Variable Air Volume (VAV) building ventilation systems, industrial and respiratory applications in medical.

VAV Press Click is supported by a mikroSDK compliant library, which includes functions that simplify software development.

VAV Press Click as its foundation uses the LMIS025B, a low differential pressure sensor that offers a digital output for reading pressure over the specified pressure span from First Sensor (part of TE Connectivity). The innovative LMI technology features superior sensitivity, especially for ultra-low pressures ranging from 0 to 25Pa / 0 to 0.25mbar (0.1 in H2O). It is based on thermal flow measurement of gas through a micro-flow channel integrated within the sensor chip.

The extremely low gas flow through the sensor ensures high immunity to dust contamination, humidity, and long tubing compared to other flow-based pressure sensors, in addition to the outstanding long-term stability, precision with patented real-time offset compensation, and linearization techniques.

The LMIS025B offers two modes of operation: Continuous mode with a 5ms sampling time which provides a near-continuous stream of pressure data, and low-power mode with a 400μA Standby current which wakes the device from Sleep to serve pressure data “on-demand”. The first measurement in either mode is available after a warm-up and conversion sequence, which takes approximately 25 ms.

VAV Press Click communicates with MCU using the standard I2C 2-Wire interface offering linearized digital output through a 16-bit sigma-delta A/D conversion. Besides, it also allows the choice of the least significant bit of its I2C peripheral address by positioning the SMD jumper labeled as ADDR SEL to an appropriate position marked as 0 and 1.

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.

• Interface: I²C
• Compatibility: mikroBUS™
• Dimensions: 42.9 x 25.4mm
• Input Voltage: 3.3V
• Pressure Measurement Range: Min. 0 mbar, Max. 0.25 mbar
• Accuracy: 0.5%
• Operating Temperature Range: Min. -40°C, Typ. +25°C, Max. +85°C

• Schematic
• LMIS025B Datasheet
• mikroSDK
• LibStock