complete project

[mschmahl]

Hello Tinkerer.
I have soldered the 18nm80 in and short circuited Pin 2+3 by my clumsiness. Now it is dead. So i have use the 6n60 again.
Here are some pictures. It is the TX-Controll-window (5V/div) and the flyback (50V/div) in 2us/div. They look´s better than the pictures from 18nm80. First picture is with 10nF Flyback-Cap. Second is with 20 nF. The flyback is reduced with the 20 nF cap for 75 V. I think, that is not so good.

[Tinkerer]

There is less current and less flyback, because of the higher resistance of the 6n60. If you have no oscillations during the rest of the cycle, it is OK to uses it as is. You can test the rest of the circuit now and change the Mosfet at a later time.

I will try to change the PIC code to add an initial delay of 100ms, before starting the TX cycles, but I have no way to test the code. Maybe somebody is willing to write some code for the PIC 16F690????????????

[charleskerr]

Tinkerer

I haven't even had a chance to study all the schematics yet, what do you need written for the pic? If I have a chance this weekend I can maybe thrash something out.

Charles

[Tinkerer]

Tinkerer

I haven't even had a chance to study all the schematics yet, what do you need written for the pic? If I have a chance this weekend I can maybe thrash something out.

Charles

Charles, thank you for the offer.
The code for the TINKERERS_SB, is just a simple timing sequence for the TX pulse and 2 sample pulses.
To avoid the problem at switch ON, we need to add a delay of about 100ms, initially, to give the storage capacitors the time to charge fully.
I can send you my asm file by email, to change, or you could just write a whole new one.

There are of course many more features we could implement with the PIC16F690, it is just a matter of writing the code and add the hardware to the simple basic circuit.

Thanks for the help.

Tinkerer

[mschmahl]

Hello Tinkerer,
now i have some new fet´s, so i can test the Tinkerer_SB more. My TX-Board look´s good only the flyback-voltage is a bit weak, about 330 V. This could be better with the new timing.
Can i get the original-file for the Pic?
Thank´s a lot.

[mschmahl]

The tinkerer_sb is working. After rewound my RX-coil all is better now.
Here are some clip´s.
The paper-roll in the mid of the coil is 30 cm long. All is done without the BU controll connected. It is not easy to find the point, where i get the tinkerer_sb working and with switching off and than on i have to find this point again.
But when it is working, it is very nice.
For silver, cooper, gold the tone goes higher. For iron and steel the tone goes deeper or get away.
Sorry for the bad quality of this clip´s. You have to turn up the volume full.

[mschmahl]

Video 2 with small Goldcoin 10mm

[mschmahl]

And Video 3 With bigger Goldcoin 22mm

[tmiller1079]

Hi Tinkerer et al,

I have wanted a metal detector for many years, and have resolved that it is time to think about building one. (I built a Jaycar kit once, but it was oversimplified and was just too painful in the field, requiring continuous adjustment). I've been reading through this and other pages on GeoTech forums, and I have to say it's been quite an education!

Congrats on all the development work you guys have put in. I only wish I could bring something to the table, but you are operating way over my head!

[Qiaozhi]

Hi Tinkerer et al,

I have wanted a metal detector for many years, and have resolved that it is time to think about building one. (I built a Jaycar kit once, but it was oversimplified and was just too painful in the field, requiring continuous adjustment). I've been reading through this and other pages on GeoTech forums, and I have to say it's been quite an education!

Congrats on all the development work you guys have put in. I only wish I could bring something to the table, but you are operating way over my head!

Perhaps you need to read Inside the METAL DETECTOR - Published September 2012

[Tinkerer]

It has been a long time, but finally I can get back to my hobby of tinkering with metal detector design.
The TINKERERS design still looks interesting. I want to spend more time on it. One of the interesting parts of it, is the possibility of classifying the targets to their TC, or time constants.
Could we use the time constant for Ground Balance? It seems that the aggressive ground has a relatively constant time constant, while the desired targets have a very wide variety of time constants (TC).
With PI detectors, the targets as well as the ground respond with signal amplitude as well as with a TC.

How can we separate the target amplitude from the target TC? This will be the first project.

I have an idea..... maybe there are some other ideas out there?
Anyone? Any ideas?
Let's hear...

[6666]

Hi Tinkerer
do you have any audio files online which give a demo of your vco audio ?

[Tinkerer]

Hi Tinkerer
do you have any audio files online which give a demo of your vco audio ?

I lost practically everything. The laptop and the external hard disk ceased to work. They stole the coils out of the boxes I shipped and destroyed whatever they could destroy. I am left with a box full of parts, all mixed up, since they emptied about half the sorting boxes into one big box.

It is nearly back to zero. The best repository is what is on the TINKERER IB-PI FORUM, here.

So, up to a new start.

The vco? I used an old 4046. The center frequency, with the frequency going high on gold and low on iron seemed a good idea.

Bugs recently posed a better version with the same IC. It might be a good idea to try his circuit. I wonder if he let's us post it here?

The 4046 has another feature that he is not using. That is the enable pin. Controlling the enable pin with the PIC, to avoid the squeel at start-up or to establish a no audio noise band might be useful.

Since we start from scratch, let's kick some ideas around.............

[Davor]

I'm about to implement my audio modulator that converts DC target response to sinus in a span of about an octave and completely proportional. Simulation sound is nice and I'm itching to try it in RL. It sounds very non-irritating, and it performs as a real 4 quadrant multiplier, a real balanced modulator.

[Tinkerer]

I'm about to implement my audio modulator that converts DC target response to sinus in a span of about an octave and completely proportional. Simulation sound is nice and I'm itching to try it in RL. It sounds very non-irritating, and it performs as a real 4 quadrant multiplier, a real balanced modulator.

This sounds very interesting. Sine wave is so much kinder to the ear. How much power does it consume? Can we see a circuit?