Whites Surf PI schematic

[chocochips]

update!

I managed to get a waveform like the one in the picture. (I simulated the circuit on multisim cuz I havent got a photo yet.)

The white trail is when there are no metal objects detected.
The red trail is when there is a metal object.
In other words in the presence of a metal the wave takes slightly longer to get back to 0V.

The picture is grossly inaccurate but I hope I managed to get my point across. :P



Am I on the right track?

Lastly, the range that Ive got was disappointing. It appears that there isnt enough depth, as the coil was only 3-4 cm away from the metal object to get a response like the one in the picture.

[chocochips]

Like stated, NOPE!

The signal would be meaningless. The signal has to be in the slice of time that reflects the target response.

No, you cannot do away with the CD4066 IC. It is not used for disc but is used as a gate to sample the decay curve.

Oh my, does it mean I would have to build the whole chunk?

I have got not much time left for this project so I need to find a shortcut

How about linking the wire from Q1's emitter to the switches?

I'd imagine the Schmitt Triggers are made to close the switches when Q1's emitter goes to 12V (which is when the timers output goes to 0V) after the series inverting outputs.



Thanks again guys!

[homefire]

Like stated, NOPE!

The signal would be meaningless. The signal has to be in the slice of time that reflects the target response.

[dfbowers]

Hello!

Do you think I can do away with the two CD4066s? Because I am not looking at the discrimination bit of the metal detector.

If so, is it possible to replace them with wires only? (And the input to the op amp would the same, right? =\)

Please advise, thank you.

No, you cannot do away with the CD4066 IC. It is not used for disc but is used as a gate to sample the decay curve.

[chocochips]

Look at the signal after the sample has been taken here.

Hello!

Do you think I can do away with the two CD4066s? Because I am not looking at the discrimination bit of the metal detector.

If so, is it possible to replace them with wires only? (And the input to the op amp would the same, right? =\)

Please advise, thank you.

[homefire]

Look at the signal after the sample has been taken here.

[chocochips]

You have more signal to work with after the Integrator.

Thanks for replying.

Sorry but I don't really understand your post.

Isn't the integrator used to amplifying the signal from the sampling circuit?

So I would think that using an oscilloscope will be good enough for the job, right?

Please kindly advise, thank you!!

On another note, thanks QiaoZhi!

I managed to find most of the answers that I need!

[homefire]

You have more signal to work with after the Integrator.

[Qiaozhi]

Hello guys!

I have built a part of the circuit, namely the timer circuit until the input to the NP5534P op-amp. The plan is to power the circuit using PSUs and using oscilloscope to detect any changes in the waveforms.

The timer is working fine, but I cannot understand the output from the circuit; when in contact with a metal, the only observed change is a slightly steeper slope to 0V. Am I on the right track here?

I have attached two images to illustrate the question.

Lastly, can anyone please explain the purpose of each components please? (Except for the timer components) I can't find them on google

Thank you so much!

If you read some of the PI articles / projects here ->

http://www.geotech1.com/cgi-bin/pages/common/index.pl?page=metdet&file=projects.dat

you will find answers to all your questions.

[chocochips]

Hello guys!

I have built a part of the circuit, namely the timer circuit until the input to the NP5534P op-amp. The plan is to power the circuit using PSUs and using oscilloscope to detect any changes in the waveforms.

The timer is working fine, but I cannot understand the output from the circuit; when in contact with a metal, the only observed change is a slightly steeper slope to 0V. Am I on the right track here?

I have attached two images to illustrate the question.

Lastly, can anyone please explain the purpose of each components please? (Except for the timer components) I can't find them on google

Thank you so much!

BEFORE


AFTER

[bernte_one]

ok it works only set an ic not 100% correct had to press it harder in the socket
i can be so easy

[nelson]

Ok and thanks
Yes i will check everything and what you said is possible too. It happends to me , with one of my Delta Pulse.
Regards
Nelson

ok thanks until here
i will give a post for my results after that weekend


....wife where is my new solder iron?


@ nelson in another forum from another detector i have read about broken trimmers or pots that can be they have a mechnical part check them

[bernte_one]

ok thanks until here
i will give a post for my results after that weekend


....wife where is my new solder iron?


@ nelson in another forum from another detector i have read about broken trimmers or pots that can be they have a mechnical part check them

[mehdi]

hello mehdi thx

for q6 i use mpsa13 ( no change in position)
for q1 i use 2n3906 have it to turn 180degree (the bow shows at top)

will try it with original parts again

as you shown


if nothing goes:
if anyone sells a working singleside Pcb i would buy it (pcb with components)
the housings for long version a hard to find and to handle with the oxygenboard i could use a standard housing (plastic box) and not a pipe

all the best

[taliesin]

hello mehdi thx

for q6 i use mpsa13 ( no change in position)
for q1 i use 2n3906 have it to turn 180degree (the bow shows at top)

will try it with original parts again

as you shown


if nothing goes:
if anyone sells a working singleside Pcb i would buy it (pcb with components)
the housings for long version a hard to find and to handle with the oxygenboard i could use a standard housing (plastic box) and not a pipe

i used the oxygenboard the last one with all the corrections. seems to work ok.still shy of depth compared to other reports of the surf pi.