Motion/NonMotion Mod

[Silver Dollar]

As Qiaozhi suggested here is a way to do a motion nonmotion switch on the minipulse;

[sinclairuser]

has anyone tried this mod?, a non motion mode would be great for me.

[Davor]

I simply "hardcoded" the non-motion to my (unfinished) board as per original minipulse. Makes lots more sense.
I'll also put the absolute value circuit in front of the VCO.

[sinclairuser]

ok thanks davor.

[Silver Dollar]

I'll also put the absolute value circuit in front of the VCO

Davor, What does the Absolute Value do for you?

[Davor]

When you apply a GB sample, the response of targets is split in two parts according to their tc. Shorter tc-s having positive, longer tc-s having negative value, and a famous hole in between. Since a VCO is affected only by a positive going signal, to have any indication of the negative going ones requires an absolute value circuit.

[Qiaozhi]

When you apply a GB sample, the response of targets is split in two parts according to their tc. Shorter tc-s having positive, longer tc-s having negative value, and a famous hole in between. Since a VCO is affected only by a positive going signal, to have any indication of the negative going ones requires an absolute value circuit.

Or you do what White's TDI does, and have a different tone depending on whether the signal goes positive or negative. This helps to distinguish somewhat between high and low conductivity targets.

[WM6]

Or you do what White's TDI does, and have a different tone depending on whether the signal goes positive or negative. This helps to distinguish somewhat between high and low conductivity targets.

This could be interesting proposal, can you suggest solution schematic means?

[Qiaozhi]

This could be interesting proposal, can you suggest solution schematic means?

This can most easily be achieved with a processor.
CAS is probably in the best position at the moment to implement this.

[WM6]

This can most easily be achieved with a processor.
CAS is probably in the best position at the moment to implement this.

Thanks. I am not happy with some sort of u-controller in MPP schematic. Not interested in such one solution.

[Davor]

Two tone would require a completely different audio section, and it can be done in a separate board. I had something of a kind in mind, but first I want to exploit whatever is in this simple VCO design.

I already posted my simple absolute value circuit at topic Started to Build the MP that can be added to MP with almost no modifications - that circuit is inserted instead of R35, R36, and Q6, and only a -5V connection is extra. The offset is set by the existing audio potentiometer, and it remains a Mini Pulse plus.

[Qiaozhi]

Thanks. I am not happy with some sort of u-controller in MPP schematic. Not interested in such one solution.

To implement this solution, you will need to lose the VCO audio. Without a processor, it would be necessary to design a window comparator, and either enable one of two separate audio oscillators, or a single oscillator with a switchable tone. Either way, it's going to take a lot of extra hardware.
A small PIC processor would be much simpler.

[Davor]

Precisely, but I'd go for the classic anyway. Can't beat the classic.