IIS3DWB | Arduino sketches for ST 's IIS3DWB vibration analyzer

IIS3DWB is a C++ library typically used in Internet of Things (IoT), Arduino applications. IIS3DWB has no bugs, it has no vulnerabilities and it has low support. You can download it from GitHub.

From the data sheet: "The IIS3DWB is a system-in-package featuring a 3-axis digital vibration sensor with low noise over an ultra-wide and flat frequency range. The wide bandwidth, low noise, very stable and repeatable sensitivity, together with the capability of operating over an extended temperature range (up to +105 C), make the device particularly suitable for vibration monitoring in industrial applications.". The flat frequency range is 0 Hz to 6300 Hz (-3 dB bandwidth) with a 26667 Hz sample rate. The device has a large FIFO that can hold up to 3072 bytes of data, enough for 512 accelerometer data samples. The sketch is intended to be run on a Dragonfly development board at 80 MHz. The sensor uses the SPI interface for full functionality and fast data transfer. Maximum SPI clock is 10 MHz, which the Dragonfly can support at its 80 MHz CPU clock speed. The basic sketch shows how to configure the sensor, including setting up a data ready interrupt on INT1 and an activity recognition (i.e., wakeup) interrupt on INT2, how to read the data, how to power down and power up the sensor, etc. Second sketch shows how to set up the FIFO, collect accel data in the FIFO, set up the FIFO watermark and FIFO-full (watermark) interrupt, and then batch read the FIFO into a buffer for further processing on the host. Further processing includes FFT and power spectrum peak identification, etc. We are reading the entire FIFO in one operation and subsequently constructing the data bytes rather than doing this all sequentially. Full (512 data samples) FIFO buffer read time is ~3.1 ms. Theoretical read time should be (512 samples x 7 bytes/sample x 8 bits/byte)/10 MHz = 2.87 ms so we are above 93% efficiency with > 15 ms of headroom. Next steps are to test the IIS3DWB against a known vibrational source for accuracy and, after that, add a PDM mic for an overlapping frequency range sensitivity between 100 Hz and 40 kHz. The challenge will be to maintain full data and fft throughput on both data streams without collisions.