Treasure Products Vibra Probe 580, Pulse Induction Pin Pointer...what Khz Frequency ?

[ToddB66]

Hi !

I have a Vibra Probe 580 Pin Pointer, received from Treasure Products July 26, 2017.

It has PI (Pulse Induction) circuitry, but I would also like to know the Khz frequency.
Can anyone help with that ?

Thanks,
ToddB66

[Polymer]

I have an old Vibraprobe 560 from the year 2004.

It pulses every 49ms. Yes that's milliseconds, had to rub my eyes and adjust oscilloscope for that.
That would be around 20.4 Pulses per second if my math is correct.

Hope this helps a bit.

[Mahally]

Hi Todd, this blog might help: https://blog.metaldetector.com/2012/...ointer-review/
thanks.

[eclipse]

No technical information so no it doesnt answer his question.

[Skippy]

20 PPS is slower than I would have expected, too. Do you think this is to maximise battery life ?

[Polymer]

20 PPS is slower than I would have expected, too. Do you think this is to maximise battery life ?

I would assume so and think its OK too, as pinpointers are usually not waved around as fast as detector coils.
Just as an example: say 10cm/s for a pinpointer & 100cm/s for a detector coil. That would leave you with 2 PPS per cm covered distance for the PP.

This topic is interesting for me as I am in the process of finishing a PI probe for my MMP E which is running at 2k PPS.

The OP question has animated me to experiment with dropping the PPS when switching from coil-mode to PP-mode.
I will see how this effects detecting distance and power savings. It would be interesting to know others insights into this.

[green]

I would assume so and think its OK too, as pinpointers are usually not waved around as fast as detector coils.
Just as an example: say 10cm/s for a pinpointer & 100cm/s for a detector coil. That would leave you with 2 PPS per cm covered distance for the PP.

This topic is interesting for me as I am in the process of finishing a PI probe for my MMP E which is running at 2k PPS.

The OP question has animated me to experiment with dropping the PPS when switching from coil-mode to PP-mode.
I will see how this effects detecting distance and power savings. It would be interesting to know others insights into this.

A normal PI integrator gain=Rfdbk/Rin*sample time*sample rate. Lowering sample rate lowers integrator gain. An attempt at MMP integrator with spice to see effect of lowering sample rate. Don't know if correct, interested in what you get when lowering sample rate with your MPP.

[eclipse]

Maybe sample widths are higher, 60-80uS or more?

[green]

Maybe sample widths are higher, 60-80uS or more?

Longer sample times can help with longer TC targets. My sim doesn't simulate the target time constant so maybe isn't valid?

[kt315]

Maybe sample widths are higher, 60-80uS or more?

sorry, long sample width we see just in deepers. so for example it is 45-50us in Delta Pulse. not sure need so long sample width being have
in the pinpointer.

[Altra]

It's possible this detector does not sample, but measures the decay period. Something like the pickini pi?

[kt315]

then this is like Pirat with soviet made op amps K157UD2. pi done on a garbage for 140USD.

[Polymer]

My VibraProbe 560 has been losing the little depth it originally had over the years.

So I decided to cut it open at the coil to see what I could do about that.

Here are some tech specs in case of interest to anyone:

Original air coil: Approx 15mm Outside, 12mm Inside, 4mm height.
Measured Inductance round 15uH. Wire thickness approx 0.3mm. Circa 30 Windings. 0.5 Ohms. Flyback round 80volts.

New coils tested:

- air coil 27uH, is not much better than original
- hollow ferrite one layer wire 58uH, is much better than original
- hollow ferrite two layers wire 165uH, is much better than original, but basically the same as the 58uH coil.

Exacter measurement of frequency this time: 20.66 PPS
Pulse width 33uS, when no coil connected 36uS ???
TX Pulse Amplitude 6.4volt.

@Altra: "It's possible this detector does not sample, but measures the decay period. Something like the pickini pi?"

Maybe the Vibraprobe does this. It certainly detects skinny gold/nickel stuff somewhat better than clunky silver or copper jewellery/coins.

If there are any measurements/tests that are of interest, say so. The coil part will be unsealed for the next few days.