How to measure low velocity

[Al Skierkiewicz]

I believe if you look through the data sheet carefully, you will find that the capacitor and bandwidth is an attempt to quiet down some noisey data. By bandwidth limiting the high frequency energy, you should get a more accurate output.
It seems that I remember someone (a thread perhaps) that discussed rapidly taking samples and averaging over 10 or fifteen ( or more) samples to look for trends. By knowing where you were before you may be able to find out where you are now.

[Joe Ross]

Originally Posted by Al Skierkiewicz

It seems that I remember someone (a thread perhaps) that discussed rapidly taking samples and averaging over 10 or fifteen ( or more) samples to look for trends. By knowing where you were before you may be able to find out where you are now.

This is the whitepaper you are thinking of: http://www.chiefdelphi.com/forums/pa...le&paperid=234

[nobtiba]

Thank you very much for your very useful information. In this pdf file it says that: "if your're integrating, you don't need to filter-the effect of improved resolution will be taken care of by the integration". Now I need integrate to change angular rate to angular, so I needn't average the samples?
In Kevin's code (gyro.h, gyro.c) the time lapse between samples decided by programmer with a timer. If this interval (time) shorter, is the angular get more exactly?

[Chris Hibner]

Originally Posted by nobtiba

Thank you very much for your very useful information. In this pdf file it says that: "if your're integrating, you don't need to filter-the effect of improved resolution will be taken care of by the integration". Now I need integrate to change angular rate to angular, so I needn't average the samples?
In Kevin's code (gyro.h, gyro.c) the time lapse between samples decided by programmer with a timer. If this interval (time) shorter, is the angular get more exactly?

You won't need to average before the integral because the integral acts like a very large average.

If the sample period (interval between samples) is shorter, the integral will be more exact. However, the sample period must be consistent from one sample to another.

[Al Skierkiewicz]

What I meant was another routine looking to see if there was movement and check to see if it was valid data before the integration process.

[nobtiba]

So I think all I have to do now are the following steps:
1. Programming the ADC in uC to get samples in free running mode
2. Since the ADC is 10 bits but a data frame to transmit to pc is 8 bits, then I have to devide it to a frame of 3 bits and another of 7bits, then send them to pc
3.In pc, my program written in turbo C receive these bytes through COM1, merge them to get 10 bits value (as origin value after ADC).Then change them to voltage and then to corresponding angular rate.(we call rate value)
4.Also in this program (in pc) I use the timer of uC in PC to count the interval between two samples.
5.Calculate: angular=angular +[(rate value i)+(rate value (i+1))]*(time interval), and loop this routine
<in the beginning angular =0>
I'm sorry if some of these steps seem to suit in programming forum, but I think if I say all things in detail, it may help you to see where is my problems.
Especialy, I don't know how to do in step 4