Delta Pulse

[Vadim18]

They are good chips, but they both wil not run in this circuit, by "common-mode input voltage range" limits.
I begin my tests with LF355, TL071, LF356. With LF355 my unit work super stable, can detect aluminium cola can to 60 cm distance with 27cm coil.
Will run with LF357 better, but not so much. Will detect more noise than signal. Main key of sensivity are integrator stage.

[6666]

I begin my tests with LF355, TL071, LF356. With LF355 my unit work super stable, can detect aluminium cola can to 60 cm distance with 27cm coil.
Will run with LF357 better,

Why are you not happy with 60cm ?, those 357 are hard to get.

[kt315]

https://www.geotech1.com/forums/show...831-Cache-Test

really testing on cache. 24 inch is 60.96cm.

[dbanner]

Big coil requires proper gauge wire, connector and cable AND correct damping.
How in the world you're gonna test 1x1 meter big coil in the lab. NO, NO! Take it to the bush!

[kt315]

Vadim18 I buy all chips and components from china. The detection depth is same for 5kg+ weight pure iron pieces of same size. The 1mx1m coil can detect these 5kg iron pieces at the same distance. This detection depth is trash. Absolute scam. It is very disappointing after spending so much effort and money. Such false claims and fake videos only to sell trash pcb. Now it is very clear why the seller of this design is always playing angry when you ask him questions about the poor performance. He will always attribute the wrong to the customer and if nothing works then will start abusive remarks and language. No wonder he would always advise to get parts from trash. Do not invest much time and money in to this. Its once in life time maybe that you would got search for train burried 15 feet deep.

i get orders again and again. despite on your negative claims.


hi

i am from (deleted for privacy) , i want to buy 2 pc's delta pulse pcb
Previusly i bought 2 pcs from you and worked great.how i must pay?

[Qiaozhi]

Vadim18 I buy all chips and components from china. The detection depth is same for 5kg+ weight pure iron pieces of same size. The 1mx1m coil can detect these 5kg iron pieces at the same distance. This detection depth is trash. Absolute scam. It is very disappointing after spending so much effort and money. Such false claims and fake videos only to sell trash pcb. Now it is very clear why the seller of this design is always playing angry when you ask him questions about the poor performance. He will always attribute the wrong to the customer and if nothing works then will start abusive remarks and language. No wonder he would always advise to get parts from trash. Do not invest much time and money in to this. Its once in life time maybe that you would got search for train burried 15 feet deep.

Chuubaba - numerous people have successfully built the Delta Pulse design, and are happy with the results. When KT315 says that his PCB design is good, you can believe him.

With all due respect, the problems you are having are caused by your lack of electronics experience. Attempting to build a sophisticated metal detector design without some basic skills, and the necessary equipment, is asking for trouble. There is no substitute for knowing what you're doing.

[chuubaba]

Big coil requires proper gauge wire, connector and cable AND correct damping.
How in the world you're gonna test 1x1 meter big coil in the lab. NO, NO! Take it to the bush!

Dbanner Now I am using 40cm coil 400uH with coax connecting cable. Total resistance of coil and cable is 3 Ohm. Is this ok? R5 is 680 Ohm 1W.

Vadim18 my LM355 and OP42 chips will arrive tomorrow. Lets see how these work with my board.

[chuubaba]

Chuubaba - numerous people have successfully built the Delta Pulse design, and are happy with the results. When KT315 says that his PCB design is good, you can believe him.

With all due respect, the problems you are having are caused by your lack of electronics experience. Attempting to build a sophisticated metal detector design without some basic skills, and the necessary equipment, is asking for trouble. There is no substitute for knowing what you're doing.

It can detect the tons of iron in my roof from 3 meters but what good is it for practicle use?
I have done the tests with 1mx1m coils as seen in many videos for this and similar detectors. As long as i am holding the target with my bare hands and walk over the coil it will be detected as far as my hands can lift in air BUT when i wear gloves or use a plastic pole to hover it above the coil then the same target will be detected at around 80cm.
Yes i lack the knowledge but i have followed instructions. I don't think any equipment is lacking but you may point out whats wanting.

[kt315]

i totally agree with you George. i only copied bulgarian layout that was checked and tested by me showing nice result.
there was just shielding importance issue that i did not still understand, but later this problem was discovered and resolved.

all the best

[dbanner]

It can detect the tons of iron in my roof from 3 meters but what good is it for practicle use?
I have done the tests with 1mx1m coils as seen in many videos for this and similar detectors. As long as i am holding the target with my bare hands and walk over the coil it will be detected as far as my hands can lift in air BUT when i wear gloves or use a plastic pole to hover it above the coil then the same target will be detected at around 80cm.
Yes i lack the knowledge but i have followed instructions. I don't think any equipment is lacking but you may point out whats wanting.

My goodness. hope you remembered to remove your wristwatch and belt that's holding up the pants. And eyeglasses with metal frame,

Chuub, take a break, go into nearby town, look for delicious female to go damping with. I mean't camping with. Oh dear lord.

[dbanner]

By the way, it is important to know the difference between a log pot and a lin pot, they are not interchangeable! Some people just stick any old pot into circuit and expect good results, not so.
One must pay attention to correct type of pots for particular controls. A100K and B100K are not the same pot. This is often overlooked by young players.
Also, some people use trimpots for real pots without realizing there is something known as turn cycles which limits trimpots before failure ocurrs. And it is not complete rotation cycle but it could be just back and forth cycle over a small part of track before failure on that specific portion of the track. I once saw pics of delta pulse home brew PCB with such trimpots used for front panel controls, limited to just 200 cycles according to datasheet.
A recipe for magic smoke on pulse width.

[chuubaba]

My goodness. hope you remembered to remove your wristwatch and belt that's holding up the pants. And eyeglasses with metal frame,

Chuub, take a break, go into nearby town, look for delicious female to go damping with. I mean't camping with. Oh dear lord.

I had no metal on me except the target (32cmx14cm 1kg iron box). It was not detected beyond 80+- cm when i used plastic gloves or plastic pole to hover it above the coil. I am 5'.11")

[chuubaba]

By the way, it is important to know the difference between a log pot and a lin pot, they are not interchangeable! Some people just stick any old pot into circuit and expect good results, not so.
One must pay attention to correct type of pots for particular controls. A100K and B100K are not the same pot. This is often overlooked by young players.
Also, some people use trimpots for real pots without realizing there is something known as turn cycles which limits trimpots before failure ocurrs. And it is not complete rotation cycle but it could be just back and forth cycle over a small part of track before failure on that specific portion of the track. I once saw pics of delta pulse home brew PCB with such trimpots used for front panel controls, limited to just 200 cycles according to datasheet.
A recipe for magic smoke on pulse width.

I got the "potentiometers" from aliexpress but no info on data. There have been moments when i did suspect some smoke but the pots always read correct values on DMM. I test them as shown in youtube videos.
BTW there are few issues. Firstly it does not detect fast moving target near the limits of detection depth. Also it keeps ringing for some moments after a target has passed the coil. And finally the GEB and SENS pot make it most noisy instead of helping eliminate noise. With TL071 and LF357 the DISC pot does the same so i have to keep these three to minimum position. And finally i am amazed why MOSFET and VD1 don't get hot.

[chuubaba]

............One must pay attention to correct type of pots for particular controls........
........

Thank you for highlighting this. All pots on front panel of my board are "B".
Kindly elaborate more on correct choice for each front panel pot. Thank you again

[dbanner]

Thank you for highlighting this. All pots on front panel of my board are "B".
Kindly elaborate more on correct choice for each front panel pot. Thank you again

Yes, you have the correct pots.
Potentiometers with B designation are linear taper, so this is correct for all the front panel pots in the circuit.