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I'm looking for an accelerometer with about 1 kHz frequency response (~1 ms response time.)

I found two components which I think might be adequate, but I'm not sure since I can't properly understand their datasheets.

These are the two components:

  1. ADXL345
  2. ADXL377

I'd be grateful if anyone could explain to me which field should I look at when reading those datasheets in order to understand the device's response time (or frequency response like here which was more clear to me.)

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1 Answer 1

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You've picked some very different accelerometers there.

The ADXL345 is a digital accelerometer - it delivers acceleration values over a digital SPI or I2C bus.

The ADXL and the TE 4020 are both analog models - the accelerometer output is an analog value you will have to digitize.

For the ADXL345, you can select the desired data rate via a digital command to the device.

The available data rates (and the corresponding sensor bandwidths) are given in table 7 on page 14 of the datasheet:

enter image description here

The bandwidth of the ADL377 is determined by the values of the capacitors that you connect between each axis output and ground.

The maximum bandwidth is 1000Hz - even if you don't install a filter capacitor.

From page 9 of the datasheet:

enter image description here

  • The AD345 gives you 1600 Hz or 800 Hz. You can't get 1000 Hz exactly.
  • The AD345 saves you from having three analog to digital converters (if your task requires digital processing.)
  • The AD377 gives you at most 1000 Hz.
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  • \$\begingroup\$ thank you very much for the detailed answer. do you know by any chance if there's a need for special module that connects devices which use SPI\I2C bus to Arduino? I saw some guides that connect the ADXL345 to the Arduino without any modules in between, but some other guides did use a specialized module, so I'm a bit confused. \$\endgroup\$ Commented Aug 25, 2021 at 11:41
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    \$\begingroup\$ Arduinos can "speak" SPI and I2C directly. You may need a level translator, since the ADXL345 is 3.3V only - most Arduinos use 5V logic levels. \$\endgroup\$
    – JRE
    Commented Aug 25, 2021 at 11:51
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    \$\begingroup\$ Adafruit has a library and a breakout board for the ADXL345. Have a look at their adapter. \$\endgroup\$
    – JRE
    Commented Aug 25, 2021 at 11:54
  • \$\begingroup\$ @JRE hi, I want to work with adxl345. I have a question, data rate is 3200 but bandwidth is 1600. Is this because ( A sufficient sample-rate is therefore anything larger than 2B samples per second. Equivalently, for a given sample rate f_{s}, perfect reconstruction is guaranteed possible for a bandlimit B<f_{s}/2}.) this ? \$\endgroup\$ Commented Nov 24, 2022 at 12:47
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    \$\begingroup\$ If you switch the 50Hz sampling (data rate,) it makes a measurement 50 times per second. It filters out anything faster than 25Hz because any signal faster than 25Hz would not be represented correctly when measured only 50 times per second. \$\endgroup\$
    – JRE
    Commented Nov 24, 2022 at 13:36

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