Looking for an expert in electronics to add discrimination to an Impulse MD
- Thread starter Delwin79
- Start date
I was just looking for an expert to add discrimination to an Impulse Metal Detector If someone knows let me know as soon as possible
SAGITTARIO
Tenderfoot
Hi Delvin
I've 3 Impulse unit, and I've searched someone for this mod.
I know that the intention of Dave Johnson (Impulse father) was to make it with discrimination, but for not known reason, that wasn't maded. I think that is hard to make a PI discriminating.
Impulse is great water machine, and I use it till 1997 with great finds.
Sorry for my bad english.
Ciao
Nico
I've 3 Impulse unit, and I've searched someone for this mod.
I know that the intention of Dave Johnson (Impulse father) was to make it with discrimination, but for not known reason, that wasn't maded. I think that is hard to make a PI discriminating.
Impulse is great water machine, and I use it till 1997 with great finds.
Sorry for my bad english.
Ciao
Nico
Delwin79
Jr. Member
- #5
Thread Owner
Yes I am I thought they were giving away a free metal detector ..and Yes I have had this impulse metal detector for almost 7 years now but I was living in florida when I bought it and the beach was too far away but since It doesnt have a discrimination I dont want it anymore ...I have use it several times go here everyone I am about to trade it or sell it pictures are coming out soon asking price is $300 dollars
http://forum.treasurenet.com/index.php/topic,220927.0.html
http://forum.treasurenet.com/index.php/topic,220927.0.html
UncleVinnys
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Not an expert, but I think it cannot be done - at least not as efficiently as with a VLF detector.
The VLF unit works on phase shift differences between the transmitted and the received signal. The different metals create more or less of a phase shift, and that enables the circuit to estimate what the composition of the metal is.
In Pulse Induction machines, the circuit is essentially measuring the amplitude and duration of the echo produced by the coin. The PI machine sends out a pulse, then turns off for a good portion of the cycle (like over 90% of one AC cycle), then listens for the echo. There is no phase shift involved.
I would estimate it's not too difficult to add an induction balanced pickup coil concentric with the transmit coil, and then listen for the phase shift response while the PI coil is "off", but there would be all sorts of interference from the echo, and the jury-rigged discrimination circuit would have to know when the PI coil is off. That would require some engineering integration between the discriminator and the PI circuitry - - in other words, an engineering nightmare. Seems you would have to integrate the two circuits from the start, or forgeddabout it.
My 2-cents.
The VLF unit works on phase shift differences between the transmitted and the received signal. The different metals create more or less of a phase shift, and that enables the circuit to estimate what the composition of the metal is.
In Pulse Induction machines, the circuit is essentially measuring the amplitude and duration of the echo produced by the coin. The PI machine sends out a pulse, then turns off for a good portion of the cycle (like over 90% of one AC cycle), then listens for the echo. There is no phase shift involved.
I would estimate it's not too difficult to add an induction balanced pickup coil concentric with the transmit coil, and then listen for the phase shift response while the PI coil is "off", but there would be all sorts of interference from the echo, and the jury-rigged discrimination circuit would have to know when the PI coil is off. That would require some engineering integration between the discriminator and the PI circuitry - - in other words, an engineering nightmare. Seems you would have to integrate the two circuits from the start, or forgeddabout it.
My 2-cents.
Joe(TX)
Hero Member
..............I just wanted to update this thread...............Delwin sold his Fisher Impulse.......hopefully he found something better for his liking!!...............Too bad.............. any of the water proof Pulse detectors are very good for the beach where a lot of gold and silver jewelry is lost every year!! But these are specialty detectors ...........I would not use one around an old homesite or even a schoolsite!! GOOD LUCK DELWIN.......................JOE
UncleVinnys
Bronze Member
- Joined
- Dec 27, 2007
- Messages
- 1,150
- Reaction score
- 171
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- 0
- Location
- Hancock Street, Folsom, CA
- Detector(s) used
- Minelab Equinox 600
Thanks Joe.
Well, Now that I denied it could be done, I hear that one manufacturer is soon to come out with a detector that uses both Pulse Induction AND phase shift.
Forgot where I saw that, but it is bound to happen.
I expect it would be an expensive machine.
V
Well, Now that I denied it could be done, I hear that one manufacturer is soon to come out with a detector that uses both Pulse Induction AND phase shift.
Forgot where I saw that, but it is bound to happen.
I expect it would be an expensive machine.
V
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