Moodz' Awesome Gold Pulse Induction Version 3 - MAGPI V3 Project

[KingJL]

... Additionally anything ( like the ground ) that causes a change ... even slightly of the L or C of the coil will cause the loop control to move and again warble or false targeting.

I did notice that it tended to damp out targets (like you say "anything that causes a change").
JLK

[moodz]

I did notice that it tended to damp out targets (like you say "anything that causes a change").
JLK

... hmmm actually now that I think about it its a motion detector .. prob not suitable as a probe.

moodz.

[jeep6789]

Hello, everyone! Is this detector ready to use? I want to do one to probe, will it work better than delta? Thank you all

[jeep6789]

I feel that 5v is used to supply power to the coil, its induction distance will be very low, I wonder if it can be increased to 12v, to increase the energy of the coil, 7805... 7909 chip itself is very noisy, must use low noise ldo,

[moodz]

I feel that 5v is used to supply power to the coil, its induction distance will be very low, I wonder if it can be increased to 12v, to increase the energy of the coil, 7805... 7909 chip itself is very noisy, must use low noise ldo,

Hi there Jeep ...

The power on this unit cannot be increased as it uses active damping that damps the coil in a bit over 1 microsecond ... if the TX voltage is increased then the coil current will increase and the flyback voltage will increase beyond the avalanche voltage of the TX mosfet.
If the mosfet avalanches the detector sensitivity will not increase.

The EMI and noise in the environment far exceeds the noise contribution of the linear regulators ... so this is not an issue ... If you want change them out ... if it does make a difference ( which I doubt ) then we can roll your suggestion back into the design.

The default unit with a 10 inch monocoil can detect a 0.1 gram gold nugget at 3 - 4 cm or a 10cm X 10cm foil target at 80cm plus. The default settings are good for beach detector and mild mineralisation.

moodz

[jeep6789]

Can anyone upload the test mp4 of this machine?

[Rick S]

Moodz,
Working with U6 TC4428CPA that generates the -9v supply. I am only coming up with -5.1v on the output of L79L09. My understanding that voltage regulator feeding voltage needs to be at least a few volts above the require voltage.
-9v it would require -10v to -11v volts to keep a steady output voltage. So far the output is -5.1v. U6 pins 5 and 7 outputs are +4.01v. I don't see the necessary voltage for the -9v regulator. Max voltage to the whole pcb is +8.4v(2 li-ion batteries). Checked the orientation and values of diodes, caps many times.
All the other voltages are working fine, +5.0v, +3.2v. Any pointers would be helpful.

[moodz]

Moodz,
Working with U6 TC4428CPA that generates the -9v supply. I am only coming up with -5.1v on the output of L79L09. My understanding that voltage regulator feeding voltage needs to be at least a few volts above the require voltage.
-9v it would require -10v to -11v volts to keep a steady output voltage. So far the output is -5.1v. U6 pins 5 and 7 outputs are +4.01v. I don't see the necessary voltage for the -9v regulator. Max voltage to the whole pcb is +8.4v(2 li-ion batteries). Checked the orientation and values of diodes, caps many times.
All the other voltages are working fine, +5.0v, +3.2v. Any pointers would be helpful.

Hi Rick ... you probably have the diodes in the inverter configuration ( 12 volt operation ) instead of the double inverter configuration ( 7.4 volt lithium operation ). See post #23 https://www.geotech1.com/forums/foru...820#post409820. The same PCB layout still works. ( 3 diodes only required )
moodz

[Rick S]

Moodz,
I am using 3 diodes as mentioned. I up the voltage to 12v and -9v issue has been solved. Reading is -8.9v. Thanks for the direction.


Ricks

[moodz]

Moodz,
I am using 3 diodes as mentioned. I up the voltage to 12v and -9v issue has been solved. Reading is -8.9v. Thanks for the direction.


Ricks

hmm ... mine works OK on 7 volts.

[Rick S]

Moodz or anyone else,
I am going down the hard road making a circuit and coil. I will have to try -7v on the -9v regulator (Moodz). I have some left over coils from past PI projects to see what I
have put together works. I have sound coming out of the speaker which is good.
The coil needs to be like ML 300 uh @ 0.5 ohms with at Q of about 2.5? The coil I tried was 301 uh @ 1.89 ohms, Q = 1.00 and shielding 83pf all tested at 1khz. It appears it doesn't work because all
was herd was load noise and no sound difference when metal was moved across the coil. The coil pulled down the 5v and -9v voltage supply by about half. I have read that coil resistance under 1 ohm should work.
I am now under way to make a coil with ML numbers in mind. I am using litz wire 65/36 awg(.125mm) to make a 10" coil. The
Litz wire that ML uses is 72/ .125mm(36 awg)? I am still waiting for my LCD in L.A. distribution center, California. I live in Wyoming, USA.


RickS

[IBGold]

Moodz or anyone else,
I am going down the hard road making a circuit and coil. I will have to try -7v on the -9v regulator (Moodz). I have some left over coils from past PI projects to see what I
have put together works. I have sound coming out of the speaker which is good.
The coil needs to be like ML 300 uh @ 0.5 ohms with at Q of about 2.5? The coil I tried was 301 uh @ 1.89 ohms, Q = 1.00 and shielding 83pf all tested at 1khz. It appears it doesn't work because all
was herd was load noise and no sound difference when metal was moved across the coil. The coil pulled down the 5v and -9v voltage supply by about half. I have read that coil resistance under 1 ohm should work.
I am now under way to make a coil with ML numbers in mind. I am using litz wire 65/36 awg(.125mm) to make a 10" coil. The
Litz wire that ML uses is 72/ .125mm(36 awg)? I am still waiting for my LCD in L.A. distribution center, California. I live in Wyoming, USA.


RickS

Rick for your 10" coil try 32/.2 Litz that will do the job for you for larger coils 36/.2 is good. 300 uh and 0.4 ohms are the actual Mindlab specifications any where from .35 to .5 is OK.

Regards, Ian.

[Rick S]

Moodz,
I just realized that I will have to deal with the damping resistor R1 to get proper coil response. I have done the upgrades and the damping option 1. What other
adjustments are there that can be made?
Resistors down on the coil or at the plug where the coax connects to the Pcb? Making a coil close to ML will help a lot tuning the coil to the front end. That is why you are using a 10" mono ML coil.
Still looking at the two loops and how they function together. Still thinking TDI, CS6, Hammer Head and Gold Max.

RickS

[Rick S]

IBGold,

Thanks for the info on ML coils. Greatly appreciated.

[darov922]

Rick for your 10" coil try 32/.2 Litz that will do the job for you for larger coils 36/.2 is good. 300 uh and 0.4 ohms are the actual Mindlab specifications any where from .35 to .5 is OK.

Regards, Ian.

IAN: really thank you for the information you have given...i plan to make the coil and also the litz wire...although i want to know how many strands of AWG 32 does the 10" ML coil have? i did a quick calculation and to reach the 0.4 Ohms I need 20 wires. Can you guide me a bit, Thank you very much again.

Dario