Tesoro Lobo news

[maxbiri]

Hi Eugene

But you are printing my pcb design? remember that i havent good results!
I hope you will have results better than me.
I will search in old backup if i have again documentations about this design.

Bye Max

[amtech2005]

Brand New Lobo Re-Work , Hot off the Press Today !!

Maxbiri . Here is the Brand New Lobo RE-WORK !!!! I am looking for the sprint file now .

If I was a forum administrator I would delete all my previous pcb Lobo files I posted with errors !!!

But its ok , learning from mistakes is how we make metal detector circuits better !!!


Best Regards...................Eugene

[amtech2005]

REV.2.0 fixed !!

Here is the latest rev. 2.0 Lobo PCB and rev. 2.0 Lobo Component overlay :

Best Regards..............Eugene

[zoomix]

Lobo of redram

Hi all,

I too want too make this detector.

I realized Redram PCBs that I found are on site. I realized the coil Foma as in the diagram. I'm still doing tests. I can already say that I had to remove the capacitor 47NF in Tx for this to work.

Like the pictures, I soldered the capacitors near the coils and on the pcb. RX: 6.8Nf and I will do tests with a smaller capacitor on TX

The case is too sensitive (hand effect) when I touch the pot or when I pass the hand rapidly over the box it sounds. I think the sensitivity of the op amp??? if someone has an idea

I make corrections on discrimination of Foma: replace the 100k by 470K.

I can not have the sensitivity as the video redram

thank you for your advice

PS: all the components are in stock at Farnell.com (except some capacitor)

[amtech2005]

Making progress now !!

I got 4 pcb's almost ready . Just waiting for my " PCB Drill Press Kit" . I broke 4 expensive drill bits yesterday so I decided to buy a new PCB drill press kit , should be here on Wednesday. I know this Lobo will be a great project , fun to build and field test !!
see my 1st attachment:


Best Regards.................Eugene

[bernte_one]

hello

i want to see it working
my board is drilled and tinned and waits here for components but i dont know if its tested already

so if anyone can show it please post it here
http://www.geotech1.com/forums/showt...t=17538&page=2

regards bernd

[zoomix]

Test lobo and coil

Hi,

first time, i make coil just with voltmeter for mesured resistance of coil.
when électronique pcb finished and After few bad test , i make de LC meter with pic 16f628 for mesured rx and tx

http://ironbark.bendigo.latrobe.edu....lc/index2.html

I mesured the coil rx and tx

may be the error on the drawing's foma because i have this value:

Rx= 164tr 0.22mm ----mesured 28.19 mH (50.5ohm)
Tx= 60tr 0.28 ---mesured 2.615 mH (11ohm)
the calcul of thomson formule give un condensateur 24Nf on TX for 20Khz or 31nF
for 17.5Khz
2.7nF for RX if fréquence is 18.1Khz

The best test give : coin 2euro at 20cm over the coil.

-The électronic is not verry stability. There is (hand effect)
-the Pot(gain) on VR1 is not hight, just on the midle
-i replaced R10 by 470k
i am little lost because i see there is again modification on your pcb and drawing
électronic

I make a new coil with the good value L for the new test

I dont now if is important and i don't tested but i think the R44 is 48.7k and not 49.7K.
You can see the original drawing LOBO 10-03-89, there is two 48.7K

May be, can you give me the last modifications électronic that you now fonctional
thank you

[zoomix]

Lobo it's ok...BIG MACHINE

Hi,

The schématic foma has little error but after correction all it's ok. It is possible to improve dicrimination

thank you legaucho et ametech. the package lobo.rar 17Mb is verry useful.

correction:
adding 51k on dicri. (not present on schemati foma) and 82k for R10 (see rar file)

Futur test:
replace r17, r19, r20 (23.2k) by 21.2k
G.B has two potentiometre. 1 pot 100k on pcb and 1 pot 100k on face. (see schematic "TESORO LOBO W.L 6/90". for me it's the best schematic.

30cm and more on 2euro coin
25-27 on 20cent euro
discri Aluminium-GOLD very interesting

you can see result on youtube:

http://www.youtube.com/watch?v=u168T...ature=youtu.be

[perdica 2]

go with 22n on RX (10mh - 50ohm) to produce phase shift -12deg
no changes on pre-amp

[perdica 2]

20kh 22n
17.5kh 33n

[amtech2005]

Best Work so far !!!

Hi,

The schématic foma has little error but after correction all it's ok. It is possible to improve dicrimination

thank you legaucho et ametech. the package lobo.rar 17Mb is verry useful.

correction:
adding 51k on dicri. (not present on schemati foma) and 82k for R10 (see rar file)

Futur test:
replace r17, r19, r20 (23.2k) by 21.2k
G.B has two potentiometre. 1 pot 100k on pcb and 1 pot 100k on face. (see schematic "TESORO LOBO W.L 6/90". for me it's the best schematic.

30cm and more on 2euro coin
25-27 on 20cent euro
discri Aluminium-GOLD very interesting

you can see result on youtube:

http://www.youtube.com/watch?v=u168T...ature=youtu.be

Excellent Work on the Lobo Project Zoomix , this is the most [Lobo] progress I have seen on Geotech or any other metal Detector Forum around the Globe . Congratulations !!

I am sure others have built working Lobo's but they did not post any test results like you did on you-tube . I will finish mine when I get extra time = Procrastinators Unite !!


Best Regards..................Eugene

[zoomix]

Lobo it's ok...BIG MACHINE

Hi,

Thank you Eugene. There is the website redram give very good information and result on vidéo.

But all schématic of foma don't give the good connection on G.B. For the good connection G.B see scheamtic W.L 6/90

For my tests:
I improved discri with 470k on R10 (visible on a foma schematic).

Yes Predica 2, i work with 22nf on Rx because this coil is 28.15 mH 50.5ohm.
I dont want 28.15mh but after make 65tr of 0.28mm and like foma's schematic i mesured with ohmeter 50.5 ohm. After i make a essential LC meter for mesured coil and discover this value

Your value is correct
i have theoritical value with formule of thomson 159/racine(LC)
24NF for 20Khz
31.5 for 17.5khz

I try other test because I think that is great machine

Thank you

[zoomix]

révision of my other message:

all schématic of foma don't give the good connection on G.B and dicri. For the good connection G.B and discri see scheamtic W.L 6/90

For predica 2;

sorry but I did not understand your message. You advise me to go down to the value of 24nf to 22nf for have -12 ° phase shift ???


best regards...

[homefire]

William Lahr Schematic.

[perdica 2]

acording to this schematic
with RX 10mh-22n-20kh (10 kh resonance give -12 deg)
28mh 8.6n 20kh