Memsic 2125 question

otlski

Hi All,

I have a question about the 2125 accelerometer.· What are the response time limits of the device, and stamp2 interface with it?· What is the cut off frequency of the accelerometer itself (assuming that it alone is the limiting factor)?· Once it is interfaced with a stamp bs2 with short-sweet, single purpose, dedicated code; how quickly can it be sampled before the response limit is reached?· I am looking to measure <2 g's· vibration up to 100 Hz with perhaps 5% accuracy at room temperature.· If 100 Hz is too fast, what will be my achievable frequency.

Thanks,

Dan

Bruce Bates

Dan -

This is at best, an indirect answer to your question, but a bit of research using this assistance should permit you to answer your own question. The Memsic 2125 data sheet should give you the response time for the device itself. Here are some timings for various BS-2 instructions, thanks to Dr. Trach Allen:
http://www.emesystems.com/BS2speed.htm

Jump down to the SPI synchronous serial section, since as I remeber the Memsic device uses an SPI or Microwire interface for communication. You will also need to investigate (in the data sheet again) whether it requires MSB or LSB data transmission, and whether the data is fetched pre- or post- the clock pulse. Then the SPI timing tables should have the remainder of the information you require.

I'm sure it would be helpful to others if you would be kind enough to post the results of your investigation. Thanks!

Regards,

Bruce Bates

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otlski

I went ahead and purchased one after reading that the device would give up at about 47 Hz.· Not quite what I wanted but I'll give it a go and report back.

Thanks,

Dan