Advise on this circuit

[fatpo]

I've earlier posted some threads about gyros. Finally I can concentrate on this.

I use a gyro from Nec Tokin and managed to set up this circuit:

The gyro gives (when still) a signal at app. 1.3[V] and in motion +- 0.3[V]. First the signal goest through a HP filter with a large tau-time (this is necesarry in order to keep the voltage level at constant velocities). After the HP filter, I low-pass filter it with a gain of app. 39 times. Now i have a BP filter with a gain of 39times. Ive also added an anti-aliasing filter of butterworth type.

Now to the question. Is my solution the optimal one? Ive used basic knowledge in electronics and filters but hesitate if its correct?? Is this the right way to handle with gyros (and this types of sensors)??

The application Im going to implement this is to detect a lowspeed velocity (thats why I amplified it so much). Its very important that the voltage level is constant at a certain velocity. When the gyro is still (not moving) I want a zero-level at 1.5[V] (vref in the circuit). Hope u understand my problem...(dont hesitate to ask if wondered...)

 

[felixc]

With such an amplification factor, the sensitivity of the gyro to temperature may become a concern to you. While you filter out the DC offset, which does shift with temperature, verify if the gain of the gyro unit is also affected with temperature, enough to disturb your measurements.

You may also need some gain adjustment, as the gain varies a bit from piece to piece.

 

[fatpo]

Thats right about the temperature and how it affects the signal, but thats also why I filter out the DC offset so that only the changes pass through. By this way I amplify only the changes, which is then added to a self-made offset at 1.5V (Vref).

Im aware of the drifts of different types such as temp,variation, time etc. My intention with this tread was to check if there are any other ways of solving/approaching this problem.