TL12000

[GeoMax]

Hi GeoMax,

All these problems in current design are true. For me, the strangest think for this design is that Asanka insists that capability for Fe/non Fe separation is more good than in most simple PI projects. Where is the reason for this or this is only his impression?

Hmm, good question. Maybe Asanka can explain. When I look closely at the TL12000 circuit, all I see is that the delay for the FE/non-FE separation is pushed back. Actually, you could do that with any detector circuit, it doesn't necessarily have to be the TL12000 circuit.

[GeoMax]

Hi Detectorist#1

I think we need to rethink this. The strategy behind the TL12000 is that it is actually only designed to reliably find "FE" objects and if they are not "FE" objects, it just assumes they are "non-FE" objects. The circuit does this through the different time delays and switching the output signal.
This is the only way I can explain the ability to distinguish between "FE/non-FE". It is actually a brilliant strategy. The only problem is that we are only shown either "non-FE" or "FE" objects and we don't know if "non-FE" objects are gold, silver or copper objects. But then again, we just want to be sure that it is not an iron object before we dig. Right?
Actually, any detector circuit should be able to do this. Some are better, some are worse. Asanka already mentioned it in one of his previous posts.

[ArchibaldSTM]

Hi ArchibaldSTM,

Both circuits worked well. But it wasn't until Geotech Members took a closer look and came up with a redesign with no design flaws that the circuit was even better than its originals. .

That's it!!! That's exactly what I'm talking about! If they said: *I'll show you a 100% working circuit and board*, then you should show what you promised. And not offer an unfinished one. I was expecting Asanka to show a WORKING circuit, but it turned out that it was also incorrect (even though it worked). He shouldn't have made such statements then. That's all....

[Detectorist#1]

Hi GeoMax,

My question is not how TL12000 makes Fe/non Fe recognition. My question is why TL12000 make this more good than many popular simple PI MD?

[GeoMax]

Hi GeoMax,

My question is not how TL12000 makes Fe/non Fe recognition. My question is why TL12000 make this more good than many popular simple PI MD?

Hi,

I'm not 100% sure but it could be because the TL12000 only samples the target signal once. Other PI designs have two samples, like the Barracuda. I don't think it's because of the use of the LF398 IC. I've also seen the PI Polones with the same FE/non-FE detection as the TL12000 and the PI Polones don't use an LF398 chip but the "distinction" works the same good as the TL12000. There are some videos about it on YouTube.

[haylaz0036]

Dear Asanka Sanjeewa, did you do the yellow painting? It seems to be working. If it is working, what is its purpose? I am asking out of curiosity.

[Asanka Sanjeewa]

My dear Detectorist#1 and GeoMax

I respect that you both are trying to improve this device.Thank you. I will help as much as I can. But for me the current state of the device is enough. As I mentioned earlier, I also made three finished devices for my friends.
I don't care about deep depth detector on the air. I need a device if a short depth of ground penetration. Indeed Barracuda, Delta pulse are very valuable tools.
But here [ Sri Lanka ] tropical country . There are very high mineral soils and mountain rocks mixed with iron particles. This device has shown the highest penetration in my personal field tests than other pi machines .Sometimes even the Admiral Ib device I built had a maximum detection capability of one and a half feet even for a large metal when going through hard rock on dry ground.Although the TX power transistor of the device was very slightly heated, it was completely solved by putting a little heat zinc. That is enough for me. But if gentlemen like you in the forum improve this further, it would be very valuable. I saw the schematic drawn by GeoMax. Thank you very much.

[Asanka Sanjeewa]

Dear Asanka Sanjeewa, did you do the yellow painting? It seems to be working. If it is working, what is its purpose? I am asking out of curiosity.

My Dear haylaz,0036
The drawing on the yellow sheet is the sheet that I uploaded earlier, painting the PCB with yellow color and drawing the COMPONENT placement with a pen. There is nothing hidden here.

[Asanka Sanjeewa]

Hi Friends
Here is my video. This is the same thing I made by painting the PCB in yellow and writing on the components placement with a pen. There is no difference at all.It was late to post this, the people who bought the device from me did not like to post it on social media. Because of that, I had to lowest [ set the mini. depth range in this moment because they didn't like to face the video ] the sensitivity of the device to make the video so that I could not see them.
https://www.youtube.com/watch?v=rxEzWSG_3Hs

[Tanu]

My dear Detectorist#1 and GeoMax

I respect that you both are trying to improve this device.Thank you. I will help as much as I can. But for me the current state of the device is enough. As I mentioned earlier, I also made three finished devices for my friends.
I don't care about deep depth detector on the air. I need a device if a short depth of ground penetration. Indeed Barracuda, Delta pulse are very valuable tools.
But here [ Sri Lanka ] tropical country . There are very high mineral soils and mountain rocks mixed with iron particles. This device has shown the highest penetration in my personal field tests than other pi machines .Sometimes even the Admiral Ib device I built had a maximum detection capability of one and a half feet even for a large metal when going through hard rock on dry ground.Although the TX power transistor of the device was very slightly heated, it was completely solved by putting a little heat zinc. That is enough for me. But if gentlemen like you in the forum improve this further, it would be very valuable. I saw the schematic drawn by GeoMax. Thank you very much.

Hi asanka
What do they find?
Gold items or Gold nugget
can i use this detector for find nuggets ?

[haylaz0036]

Dear Asanka, I watched the video. It is really nice. The iron insulation is nice. The depth is low but it works at minimum. I want to try it. I am preparing the card and materials. Will there be any change before printing the pcb? Should I print the pcb in this condition? I would be happy if you give me the pcb.

[GeoMax]

Hi Haylaz0036,

I would modify the front-end-receiver and use a NE5534 op-amp. Because this is easier to get compare to a LM709 and probably the better choice. I also would remove the connection at the 555 timer Pin 4. See post #121 for sure. If you do the modifications, the PCB needs some redesign.

[Detectorist#1]

Hi Asanka,
This video and the explanations for "min depth range" are not serious. All tests with waving of the target - not of the coil and in air - not in the ground are NOT serious! According this video, we see the next toy - not real useful MD. Please make video with real tests.

[GeoMax]

Hi Asanka,

what is the delay when discrimination time is on / off in your TL12000?

[Detectorist#1]

According me, this delay depends from the phases of the moon - all secret is hidden in the multi-turn pot - need to be find special setting point.