Delta Pulse

[Dido]

Hello! Thank you for your response. Until now I achieved good results with the following information:
coil - 50 cm diametar. Windings - 24-25. Wire -0.8 mm. Big Resistor - 1.2 kilooma 1W. In the scheme of Delta Pulse can make changes. To improve the performance of sound, to be replaced with another 555 timer.

[Unregistered xman]

HI....

Goldmont, the resistors are mostly 1/4 watt, 5% tolerance. There are a few exceptions that are illustrated in the schematic. The damping resistor should be at least 1W. It should also be able to handle 400V. You might have better luck finding a 2W resistor that will handle 400V. No harm in that, so long as you can make it fit the board. Use 2W, 400V metal film resistor for lowest noise. R5 is 1/2W. Resistors in the low level receive section should also be metal film (R5 for instance). Use matched components for R23 & R24, and R25 & R26. The precise value is not so important but both elements of each pair should be very close to each other in value. I've seen 1 part in 1000 (.1%) suggested, but that is a tall order. If you can get them within 1% that might be good enough.

The optimum voltage rating for capacitors is the voltage that it will see, plus a safety margin (25% or more) so it won't fail. Since DP is a 12V system, 16V should be adequate for the capacitors. It won't hurt if you use higher voltage, but don't use lower voltage parts unless you know what you are doing.
It looks to me from your question like you want to jump in without even reading through what has already been posted. Please try to wade through the previous posts so that you do not wear out the others with questions that have been answered before. This is not an easy beginner project. You read Geo say it was easy project...? Well, did you know that Geo has been building these things for many years. Easy for him, maybe not so easy for others. Do you have an oscilloscope to use for setup? It would be foolish to do the DP without one - just my opinion.

i ahve a question...

the oscilloscope is to set up the coil with the circuit... playing with the potentiometers?
or for what is? sorry my question i guess for you this is a stupid question but, "if you dont ask you dont learn"

[Noemio]

meter

Hi,

just a little problem: I've not been able to find a 100 µA meter. The one I found is about 150-180 µA.
What should I do to use it to full scale?
Could be a good idea to have a higer value for R37? Or a lower value for R40?

Thank You in advance

[porkluvr]

unregistered xman: I will confess my ignorance. DP has enough circuitry that is unfamiliar to me so that I would want to scope it just to try and understand what it is doing. The circuit has, for the most part been tossed into the Geotech arena, with little or no explanation of what its parts do. Some of it is obvious, but some of it is not.
If I built DP and it seemed to function OK I would still want to look at timing and flyback, also make sure the preamp is not saturating. I would want to look at everything. But, maybe I'm just funny.
If you stick to the original parts and use a certified PCB, then it should work right the very first time, right? (Not with MY luck, it wouldn't. )

I am not the best source of advice on DP because what I am doing is duplicating the 556 timer. That is the end of the similarity, so far, I'm still working out my own design. I'm not so much interested in relics, but there is gold in my town. I think it's lonely and needs attention. "I hear you, I'm coming". DP allows control over pulse frequency and pulse width completely independently, which is something that can be very useful and is not limited to a simple waveform.

Maybe I should build DP to get a better understanding of the signal processor section, and see what else I could use. But I actually have very little use for a relic hunter at this time. Still, its a thought...

Noemio, yes, lowering R37 is probably the best way to adapt a 150 or 180ua meter. Here is where someone else looked for help with the same problem (ain't no big deal):
http://forums.qrz.com/showthread.php?t=137552

[kt315]

Hi,

just a little problem: I've not been able to find a 100 µA meter. The one I found is about 150-180 µA.
What should I do to use it to full scale?
Could be a good idea to have a higer value for R37? Or a lower value for R40?

Thank You in advance

to add R37 value. for example I use 1kOhm with 100 uA meter. no need to change R40, it sets a current in time you push RESET. only on this moment.

[porkluvr]

to add R37 value. for example I use 1kOhm with 100 uA meter. no need to change R40, it sets a current in time you push RESET. only on this moment.

KT315 is right, I had it backwards. Raise R37 to allow more current for the meter.

[Noemio]

Thank You

Thank you both to KT315 and porkluvr!

Frontdesign is really a good SW!
A friend of mine told me about www.lazertran.com
do you know it?

[kt315]

I also have released this circuit for speedy battery check. one still pushbutton was been added on panel.

good luck

[nelson]

Hi to Delta Pulse experts.
I had build my fourth DP, but now i have the following problem.
My DP sems to work at inverse. How?
Well everytime i pass a metal in front of the coil, while the detector is emiting a sound, the metal stops the sound, and when i place the metal away from the coil, the sound begins. Then if i place the metal close to the coil again, the sound stops. Looks that this is working at inverse.
I hope you can understand my english, so please let me know what can be the problem.
Ohhh, i also replace all IC´s and same thing
Regards
Nelson

[Unregistered]

Hello Nelson

Please check GAİN pot tunning connections .

Regards
Erol

[nelson]

Hi Erol
I m not electronics man, so could you please let me know where to check on the schematic?
I also have a scope.
Thanks
Regards
Nelson

Hello Nelson

Please check GAİN pot tunning connections .

Regards
Erol

[erolunall]

Hello
I attached picture of it .
You can look photos
http://www.geotech1.com/forums/showt...t=8003&page=20

check soldering of gain.

I faced same problem and I saw there are a break on gain connection.


Regards
Erol

[nelson]

Many thanks Ero. This afternoon i ll chek it.
Regards
Nelson

Hello
I attached picture of it .
You can look photos
http://www.geotech1.com/forums/showt...t=8003&page=20

check soldering of gain.

I faced same problem and I saw there are a break on gain connection.


Regards
Erol

[nelson]

Hi Bob
I also have Pulse Star II with 1 by 1 meter coil. Now i need to make a smaller coils, let said, 25 by 25 or 45 by 45 cms.
I had read all your questions about homemade coil for PSII.
Now have you made finally the coil, and how did you finally contected the coil. What about the shield ground conction.
Please any help will be good.
Regards
Nelson

Thanks Ivconic for advice on building PSII universal coil,

I found this wire quite cheap (US $0.50/foot). It is 12 conductor wire. Do you think it will be suitable?

One more question: what to do with the aluminium shield wire? Is it to be connected to one of the terminal wires?

Thank you again,

Bob

[kt315]

nelson, pls answer the questions in YES NO style.

1/ I use LF357 or TL081 in pre amp.
2/ I use 0,1% and more precise R23-R26.
3/ my power supply wires go from batteries to switch 'Power On' then on C30-C31 and only after these go on the PCB.
4/ I use more than 2300 uA*hs charge value batteries.
5/ all batteries are very good and were tested by Amperemeter.
6/ I use C7=1000 uF.