TGSL 2 tones ID

[Qiaozhi]

Worth it? Probably not, but experiments are fun. Maybe another easier way to do it is out there.

That pretty well sums up the hobby.

Although there are many versions of this quote, the most common one from Thomas Edison is:
"I have not failed 10,000 times. I have successfully found 10,000 ways that will not work."

That also sums it up nicely.

[Jerry]

Although there are many versions of this quote, the most common one from Thomas Edison is:
"I have not failed 10,000 times. I have successfully found 10,000 ways that will not work."

That also sums it up nicely.

Yes it does. I forgot about that one. Very appropriate.

Jerry

[hugo]

I was not very satisfied with the two tones. Not enough differents.
I've tried to work with a channel P FET ... without success .
Then I've just reversed the command of the N FET by adding a NPN transistor (BC547).

In Audio disc mode, without signal, the FET is ON.The audio stage is connected to the PIN 5 of the CD4024 through it.
If the target is ferrous, the output of U106 still low, the FET still ON, the tone is low (PINs 5, 6 & 9 of the CD4024 connected).
If the target is non-ferrous, the output of U106 turns high, the FET switch OFF, the tone become high (PIN 5 is disconnected, only PINs 6 & 9 are actives).

[simonbaker]

I was not very satisfied with the two tones. Not enough differents.
I've tried to work with a channel P FET ... without success .
Then I've just reversed the command of the N FET by adding a NPN transistor (BC547).

In Audio disc mode, without signal, the FET is ON.The audio stage is connected to the PIN 5 of the CD4024 through it.
If the target is ferrous, the output of U106 still low, the FET still ON, the tone is low (PINs 5, 6 & 9 of the CD4024 connected).
If the target is non-ferrous, the output of U106 turns high, the FET switch OFF, the tone become high (PIN 5 is disconnected, only PINs 6 & 9 are actives).

Thanks for the continuing development!

Can you post a video showing the new tones?

-SB

[hugo]

I'll do that soon.

[hugo]

@Simonbaker
The video :
http://www.youtube.com/watch?v=5nJKw5Kyoqo

I've added a capacitor around the FET to smooth the sound.

Here is 23:38,
Good night

[simonbaker]

@Simonbaker
The video :
http://www.youtube.com/watch?v=5nJKw5Kyoqo

I've added a capacitor around the FET to smooth the sound.

Here is 23:38,
Good night

You've made yourself a nice mod there! That is a good contribution. Great job.

It would be interesting to see if it is the simplest way to do it.

Regards,

-SB

[hugo]

I think I've found why my last try with a P FET has failed.
I've used a 2SJ178. This FET has two protection diodes inside (marqued in red).
I'd better use a basic FET like a 2N5460 to do the job.
I'll let you know...

[eduardo1979]

Good job Hugo! Thanks for sharing.

[hugo]

@eduardo1979 : You're welcome !

[selim]

hugo mod pcb

[hugo]

@Selim,
Nice job !
But you better use my last schematic for the audio.
The sound is better.

Note : A small mistake on your PCB, the FET is connected to the CD4024 pin 8 instead of 9 ...

[silverdog]

Great work Hugo

With various developments over the last few months, should we be looking at incorporating this 2 tone mod onto the TGSL-EDU version and even incorporating the pads for Holyusers Geotech VDI ?

We could create TGeoSL

A Golden Sabre with 2 tones and VDI, sounds cool

Silverdog

[hugo]

Hi Silverdog,
IMHP, it's a bit too early but why not !
I have to do some more tests with a new P-FET. Maybe this weekend ...

And, as I said in the IDX-Pro VDI thread, it will be fine if Hollyuser kick the external oscillator out and use the free RA ports to do the job (up to 8 differents tones) !
But this is another story !

We could create TGeoSL

And what about an update kit for analog Tesoro's MD (Eldorado, silver/golden sabre, etc) ?

Regards,
Hugo

[silverdog]

Sure, an update kit would be good too
When your finished testing could you do a pcb in .lay format ?
If you can keep the board under 5cm x 5cm I can get them very cheap