I'm looking into measuring the vibrations of a large telescope structure. My idea was to use an ADXL355 evaluation board, connect it to a microcontroller (Arduino) and have the data written to SD card. However I want to clarify/confirm a few things before I continue:
1.Resolution: I'm expecting to measure a peak acceleration in the order of 10mg with a frequency in the order of 1Hz. If i understood it correctly, the resolution is limited by noise which in turn is related to the bandwidth, so I probably want to limit my bandwidth in order to achieve higher sensitivity (from my calculation, limiting the bandwidth to 100Hz, with the given noise density of the ADXL355 results in a total noise of 0.3mg).
My question is: Is the bandwidth limit determined by an analogous low pass filter, or by some sort of digital filtering/setting? Also, how can this limit be modified?
2.Interfacing: How "easy" is it to interface the ADXL355 with a microcontroller (eg. via SPI) for someone that is new to the topic?
Thank you in advance for your help
The ADXL355 contains both analog (internal) and digital filters. The Filter register (see page 37 of the ADXL355 datasheet) provides a user-control for the digital filter. Table 43 provides some details on the filter options that are available through the digital filter that is in the ADXL355's (internal) signal chain.
The ADXL355 team (Anthony.DeSimone tagged for comment) is working on a reference design, but I don't think that it is ready yet. So, in the interim, here is what I would recommend to someone who is starting out: