Gyro motion control

[DavidB]

I have been working with gyro chips at work lately to determine RPM and it seems the output from a gyro chip mounted near the coil could be used to adjust the filter poles for an automatic slow motion pinpoint, a slower deep target response or a faster more mineral canceling response dependent on the coil swing speed. It is just an idea that I have been toying around with.

[Carl-NC]

An accelerometer is more appropriate than a gyroscope. There are a lot of things you could do with this.

[DavidB]

I've used a lot of accells also, the gyro chips are basically an accell mounted inside of an accell. I was thinking you could sense more in any swing direction. An X and Y accell could be a better choice.

[Davor]

IMHO any kind of steering of the HPF in a motion filter is only going to make 1/f noise worse.

[Altra]

I am experimenting with this 3-axis accel/gyro. MPU-6050

https://www.sparkfun.com/products/11028

Clones on ebay for about $12

Not sure about metal detector apps? It might make a nice graphic display of taget location under the coil.
Since the peak target signal could be considered center (coin size) under the coil. Then the vector could be used to
move and display the icon on the lcd? Another is to control the SAT speed vs swing?

[scs]

The best motion filter for IB balance detector for deepht search is-C 1 MF and R-220 KOM+ DC AMPLIFIER.

[Davor]

exactly
In this case less is more.

[scs]

The best motion filter -It was discovered by of the great Bulgarian pioneered -engineer Grozdjo Grozdev 35 years ago .Created the best detectors in my country...

[Skippy]

When the CTX3030 came out, I noticed the display of multiple targets on the screen showed distances. I thought they may use a ss gyro to determine real spacing of targets, based on time-differences (from the search-coil) and sweep speed info from the gyro. I did ask the question on another forum, but no-one knew what I was talking about, I think....

[Davor]

But it is logical. The very same approach "works" when you rely on your hearing.

[DavidB]

A filter with 1 MF and 220K would be ok for an all metal channel but for the disc and gnd channel it would be pretty useless in mineralized soil wouldn't it. That cut off freq is less than 1HZ.

[Davor]

Actually it is the other way around, but according to my own observation the typical 10Hz cut-off is waaaaay too high. It's main benefit is in fighting the 1/f noise, and while the garden variety op amps suck in this department, a good chopper stabilised DC amplifier feels right at home. DC/Offset/mineralisation blocking functionality is just fine at much lower cut-off frequencies than 10Hz.

Way to go scs

[scs]

Principle schematic motion filter for bad ground.Real detector work.