Air Flow Click is a compact add-on board that contains a flow-based 2-in-1 differential pressure sensor. This board features the LHDULTRAM012UB3, LHD ULTRA series micro-flow differential pressure sensor from First Sensor (part of TE Connectivity). This pressure sensor is based on thermal flow measurement of gas through dual micro-flow channels integrated within the silicon sensor chip to effectively maximize the dynamic range of the sensor ranging from 0 to 1250Pa. An on-board MCU with an accurate 24-bit ADC provides signal processing, including response from the two sensing elements, linearization, barometric compensation and temperature correction. This Click board™ is ideal for air flow monitoring and medical applications that demand high precision, extended measurement range, and the convenience of a single device.

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

Air Flow Click as its foundation uses the LHDULTRAM012UB3, an LHD ULTRA series flow-based 2-in-1 differential pressure sensor from TE Connectivity Measurement Specialties. It consists of two combined calorimetric micro-flow channels and two sensor elements on a single chip. The first sensing element ensures precise measurement of low differential pressures with high resolution, and the second sensing element is optimized for pressures in the upper measuring range. A fast-response 24-bit onboard controller delivers precise measurement results across the entire dynamic measuring range from 0 to 1250Pa.

The specific concept of the LHDULTRAM012UB3 ensures continuous operation that is highly reliable and economically efficient in addition to the outstanding long-term stability, precision with patented real-time offset compensation, and linearization techniques. The LHD ULTRA's high flow impedance ensures product-specific insensitivity to dust/moisture as well as minimal flow leakage.

Air Flow Click provides the possibility of using both I2C and SPI interfaces with a maximum frequency of 100kHz for I2C and 1MHz 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 else the Click board™ may become unresponsive.

While the I2C interface is selected, the LHDULTRAM012UB3 allows the choice of the least significant bit (LSB) of its I2C peripheral address using the SMD jumpers labeled as A0 and A1 to an appropriate position marked as 0 and 1. Also, an additional ready signal, routed on the INT pin of the mikroBUS™ socket, is added, indicating that new data is ready for the host.

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, SPI
• Compatibility: mikroBUS™
• Dimensions: 57.15 x 25.4mm
• Input Voltage: 3.3V
• Pressure Measurement Range: Min. 0 mbar, Max. 12.5 mbar
• Accuracy: 1.5%
• Operating Temperature Range: Min. -40°C, Typ. +25°C, Max. +85°C

• Schematic
• LHDULTRAM012UB3 Datasheet
• mikroSDK
• GitHub