detector metal

[miguelsaen]

hello I have ridden this metal detector
following the steps but it does not work
if someone can take a hand I would appreciate
in the video is a diagram in which temporality is changed
in other respects I have followed everything perfectly

http://www.easytreasure.co.uk/bfo.htm

http://www.youtube.com/watch?v=es_h7...eature=related

hola he montado este detector de metales
siguiendo los pasos que se indican pero no me funciona
si alguien me puede hechar una mano se lo agradeceria

en el video hay un esquema en el que la poralidad esta cambiada
por lo demas he se

[silverdog]

what transistor did you use ?

can you post some pictures of your board ?
can you give voltages from various points in your circuit ?

[chemelec]

It Should work, If you built the Coils Correctly!

hello I have ridden this metal detector
following the steps but it does not work
if someone can take a hand I would appreciate
in the video is a diagram in which temporality is changed
in other respects I have followed everything perfectly

http://www.easytreasure.co.uk/bfo.htm

http://www.youtube.com/watch?v=es_h7...eature=related

hola he montado este detector de metales
siguiendo los pasos que se indican pero no me funciona
si alguien me puede hechar una mano se lo agradeceria

en el video hay un esquema en el que la poralidad esta cambiada
por lo demas he se

[homefire]

Recheck all transistors are in correct orientation.

Check that all Caps are correct as well.

Try to Tune the Reference Coil in different ways to obtain the beat.

Chances are the two Osc are not producing the same freq.

Do you hear anything at all when you power it up? Click , Zip sound or anything?

[miguelsaen]

detector metal

when turned on do not hear
I have the second coil with 125 echo back
and I've been removing up to 120 laps
instead listen but not all
I find it difficult to measure the frequency of the coils
since I have no oscillator
elhilo enamelled copper is 0.40 mm
And I have also tried a 0.50 mm

[silverdog]

what transistors are you using ?

[miguelsaen]

I used the 2N5551

[silverdog]

2N5551 and BC184 are 180 degree reversed for pins - have you inserted the reversed from picture on easytreasure ?

[6666]

Like this

[miguelsaen]

the position of the transistors and have taken into account
that are different
a question for the same frequency in both
Coil cable length must be the same
eg 5 meters or do not need to measure the same


la posicion de los transistores ya los he tenido en cuenta
que son diferentes
una pregunta para obtener la misma frecuencia en las dos
bobinas la longitud del cable tiene que ser la misma
por ejemplo 5 metros o no es necesari que midan lo mismo

[bernte_one]

this was the first i have build

but mine never run at a single 9v battery i used two in serie then it works
the secret is to build a good reference coil which is adjustable
take a little pipe wind the coil on it then you take a metal bolt and move it in the pipe
you will hear a frequence change at on little point it is exact tuned when you hear a motorboating sound tuk tuk tuk and not fiiiiiiieeeeep i cant explain it better

[Finderskeepers]

G'day

I'm new to this forum, new to electronics, enjoy building metal detectors and a frequent visitor to this website.

I built this detector back in April of this year with no knowledge of electrical circuitry. This project is a good introduction to building metal detectors. It was built to the exact specifications except for the npn transistors - bc337 were used. When it was time to start it up, it did not work. After a week of problem solving, I hooked up a 10k pot to the headphone jack and it was alive (there is no mention of this in the instructions). In the end I ditched the original reference coil and used a 10k pot as the threshold control in parallel with a 330uh choke. The coil was 250mm diam with 0.5mm enamelled copper wire with appprox. 18 - 19 turns. With the calculations obtained from online inductance calculators, I started with 22 turns on the search coil and slowly removed turns until it started to signal and then fixed the wire down in position when the frequency was just right.

Out on the field, this is not a good detector - requires constant adjustment of the threshold, and not so sensitive on small objects. Shortly after, I've built Gary's pulse 2 metal detector and it's a pretty good d.i.y. detector. As a CAD operator, I can draw and etch my own boards and his instructions are very clear to follow. It signaled on targets in the same patch of ground that the BFO detector couldn't. Furthermore, it is very stable and enjoyable to use. Another great project I have completed is the Baracuda legend. I have built two of them, the first from scratch and the second was a kit I purchased from Silverdog's website - his boards are very professional looking and of a high quality. It searches slightly deeper than Gary's pulse 2, the signals are more noticable on deeper targets and adjusting the threshold is very rare. A Minelab 11" commander monocoil was purchased for the Baracuda and works great, but not so good with Garys Pulse 2 on small targets. I will shortly commence building the Chance pi as I have ordered the board & programmed atmega 8 from Silverdog.

I hope that my experience with the BFO detector will help you.

Finderskeepers

[bernte_one]

G'day

I'm new to this forum, new to electronics, enjoy building metal detectors and a frequent visitor to this website.
Finderskeepers

new? i often read about a user named like you maybe other forum?

and at miguel
maybe you should start a more advanced project baracuda is very good order a kit from silverdog read something in the thread and you learn much and have fun

[miguelsaen]

hello bernte_one
I'm thinking of building a slightly more complex
the barracuda or other like that
if you can recommend me one that is not too difficult
'll try to start a project that is not very complicated due

hola bernte_one
estoy pensando en construir uno un poco mas complejo
el baracuda u otro por el estilo
si me podeis recomendar alguno que no sea muy dificil de
hacer intentare empezar por un proyecto que no sea muy complicado gracias

[miguelsaen]

hello bernte_one
try to make the barracuda but first I want to do
work that one, if you tell me the diameter of enamelled wire that you used and how many did you take in each coil turn
to try them


hola bernte_one
intentare hacer el baracuda pero primero quiero hacer
trabajar este otro, si me puedes decir el diametro del hilo esmaltado que usaste y cuantas vuelta distes en cada bobina
para intentar hacerlas