Anyone Built a DIY metal detector?
- Thread starter Marauder
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I was on Geotech for a while,(got banned for my anti-capitalist stance), and there is literally thousands of posts with people building from scratch and being unsuccessful. I'm pretty sure they just get sick of people asking why theirs don't work. Even if you are absolutely intent on building one from scratch, it may still be less heartbreak to hang the expense and buy a complete and tested board from Silverdog. That way you will have a reference point for measurement and comparison.
Apparently it's a bit like riding a bike- once you've succeeded once, it's easier next time.
When I get back to my electronics again my first major assembly will be my seccohmeter, to measure coil inductance. Then I will assemble the Surf Pro DD (pre-built and tested board) with a ML commander DD. Then the XR71. But I already have many more ideas/experiments in mind for simple BFOs and IB/BBs. I have accumulated a plethora of coil wire types, ICs, components, boxes, copper boards etc.,etc.
Even the relatively simple builds can be a perplexing nightmare from breadboard prototype to designed/printed board to assembled machine.
Good luck with it Marauder.
Apparently it's a bit like riding a bike- once you've succeeded once, it's easier next time.
When I get back to my electronics again my first major assembly will be my seccohmeter, to measure coil inductance. Then I will assemble the Surf Pro DD (pre-built and tested board) with a ML commander DD. Then the XR71. But I already have many more ideas/experiments in mind for simple BFOs and IB/BBs. I have accumulated a plethora of coil wire types, ICs, components, boxes, copper boards etc.,etc.
Even the relatively simple builds can be a perplexing nightmare from breadboard prototype to designed/printed board to assembled machine.
Good luck with it Marauder.
How has it been going Marauder?
The problems your having really shouldn't exists as I've seen many vids on surf pi boards and builds with success. I don't understand why your having to tune soo much and not getting clear sound. Most online I've seen have worked unless they reversed the capacitor polarity when soldering and turned it on.
Have you still got the other surf pi?
The problems your having really shouldn't exists as I've seen many vids on surf pi boards and builds with success. I don't understand why your having to tune soo much and not getting clear sound. Most online I've seen have worked unless they reversed the capacitor polarity when soldering and turned it on.
Have you still got the other surf pi?
Hey Marauder have you had any luck?
What area do you live in?
If you live in Vic and are ever down Geelong way you are more than welcome to drop into my workshop and we can put it on the bench and see if we can sort any issues you are having. Same goes for anyone down this way who is having issues with DIY detectors. Just send me a msg and we can organise a time.
What area do you live in?
If you live in Vic and are ever down Geelong way you are more than welcome to drop into my workshop and we can put it on the bench and see if we can sort any issues you are having. Same goes for anyone down this way who is having issues with DIY detectors. Just send me a msg and we can organise a time.
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Hey Guys,
Yeah i've had no luck, Actually a bit pissed at the whole project.
My current theory is that i've put a resistor in the wrong spot(Instead of checking the colour codes when i put them on the board i just went with the lables on the cardboard, and since i was sent the wrong IC in one package i've got doubts on the Resistors.)
Basically the detector works, but very insensitive. I've guessing that i've got a 10k where i need a 1k or something similar which is dropping the gain on the op amp.
Used to know the resistor color codes of by heart! So my next job is to check each resistor. Just had to get back to work, back to school and I've been roped into building the wife a glass blowing workshop!
I've been seriously considering building my own circuit, with an arduino brain, but I need to finish this one first.
Yeah SteelPat, I live in Geelong. Actually used to live in Ocean Grove years ago. Thanks for the offer, If i can't get it going I might take you up on that offer!
Yeah i've had no luck, Actually a bit pissed at the whole project.
My current theory is that i've put a resistor in the wrong spot(Instead of checking the colour codes when i put them on the board i just went with the lables on the cardboard, and since i was sent the wrong IC in one package i've got doubts on the Resistors.)
Basically the detector works, but very insensitive. I've guessing that i've got a 10k where i need a 1k or something similar which is dropping the gain on the op amp.
Used to know the resistor color codes of by heart! So my next job is to check each resistor. Just had to get back to work, back to school and I've been roped into building the wife a glass blowing workshop!
I've been seriously considering building my own circuit, with an arduino brain, but I need to finish this one first.
Yeah SteelPat, I live in Geelong. Actually used to live in Ocean Grove years ago. Thanks for the offer, If i can't get it going I might take you up on that offer!
G
Guest
I got my secohmmeter built and working- this measures the inductance without the need or understanding of a CRO. You need 0volts between pin 6 and earth on the (?) IC (check the web). But if you reversed the batteries inevitably something will be fried. Always check each resistor value- with a multi-meter- before soldering.
The Surf pro DD I bought off ebay is built and up and running. I started with a ML commander 10x5(380uH). Got it working good, then made a 300uH coil from .25 enamelled.
I never checked for 0volts before assembly, and I think there may be a (330R) damping resistor on this board- it was pre-tested too- because all experiments with damping it have resulted in less sensitivity. The volume is very low, but next time I dis-assemble it I will reduce the value of (R22?) for more volume. For now I use a Nokia amplified speaker. These coils are best at about 3/4 on delay pot (surf 1.2 doesn't have that). I have made a 50x30 coil, 450uH, for my Sniffer xr71-tried it on the Surf and it thumps! Over 2 foot on a $1 coin!! The delay set at about 1/4. Next experiment will be a 200-250uH coil and damping.
Sniffer is all laid out and board going in the box today.
The sniffer from Bulgaria off ebay-I msgd the bloke about his best kit for small gold, and going for the Vandal pulse2 next- a 3 frequency Pi design- he also has a fully built Vandal vlf detecor for about $400.
Marauder, I suggest you save yourself the grief and buy the secohmmeter kit(ebay $17) and another board.
Good luck with it mate- perseverance and the process of elimination is all that is needed.
The Surf pro DD I bought off ebay is built and up and running. I started with a ML commander 10x5(380uH). Got it working good, then made a 300uH coil from .25 enamelled.
I never checked for 0volts before assembly, and I think there may be a (330R) damping resistor on this board- it was pre-tested too- because all experiments with damping it have resulted in less sensitivity. The volume is very low, but next time I dis-assemble it I will reduce the value of (R22?) for more volume. For now I use a Nokia amplified speaker. These coils are best at about 3/4 on delay pot (surf 1.2 doesn't have that). I have made a 50x30 coil, 450uH, for my Sniffer xr71-tried it on the Surf and it thumps! Over 2 foot on a $1 coin!! The delay set at about 1/4. Next experiment will be a 200-250uH coil and damping.
Sniffer is all laid out and board going in the box today.
The sniffer from Bulgaria off ebay-I msgd the bloke about his best kit for small gold, and going for the Vandal pulse2 next- a 3 frequency Pi design- he also has a fully built Vandal vlf detecor for about $400.
Marauder, I suggest you save yourself the grief and buy the secohmmeter kit(ebay $17) and another board.
Good luck with it mate- perseverance and the process of elimination is all that is needed.
What I.D are the opamps ?
G
Guest
I get my ICs 10 at a time from China through Ebay usually, but there are a few good, quick suppliers in Oz selling through ebay, or just go to mouser AU.
Marauder... What is the IC number? I may have one on the shelf.
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Not sure on the IC number, but don't stress I should be able to grab one from work.
Just checked all the resistors, resistor R11 is coming up as 12.5k when it should be 22k. its marked right though, so maybe its buggered. Will pull it out of the board and test it on the weekend.
maybe that will fix it?
Just checked all the resistors, resistor R11 is coming up as 12.5k when it should be 22k. its marked right though, so maybe its buggered. Will pull it out of the board and test it on the weekend.
maybe that will fix it?
G
Guest
Mate, I'd say you've burnt out one of the ICs reversing the battery.
I've been reading through another site- some absolute must do's are check and measure each R before soldering, carefully check for dry solder joints, be very careful not to get too much heat in your soldering, especially around ICs and on heavier leads. With most of these kits there are also seriesed checks after each assembly stage, so if there's a problem you find it before it causes more problems or confounds you at the end of the build. And put the ICs (of each stage) in last.
I'm a stubborn tinkerer and problem eliminator, but I'd be tempted to start again in this situation.
I'm pretty sure Geotech has a step-by-step guide for building the Surf. As with all websites it's best to have a womans look first- the mods get absolutely fed up with answering questions over and over when the comprehensive answer is only a few pages back, or in the relevant section.
Good luck mate.
I've been reading through another site- some absolute must do's are check and measure each R before soldering, carefully check for dry solder joints, be very careful not to get too much heat in your soldering, especially around ICs and on heavier leads. With most of these kits there are also seriesed checks after each assembly stage, so if there's a problem you find it before it causes more problems or confounds you at the end of the build. And put the ICs (of each stage) in last.
I'm a stubborn tinkerer and problem eliminator, but I'd be tempted to start again in this situation.
I'm pretty sure Geotech has a step-by-step guide for building the Surf. As with all websites it's best to have a womans look first- the mods get absolutely fed up with answering questions over and over when the comprehensive answer is only a few pages back, or in the relevant section.
Good luck mate.
I would start by checking that you have the correct supply voltages at the ic's. It's really just a process of elimination. It's the sort of work I do every day so it's pretty straight forward for me but I can understand the frustration when things don't go as they should.
As I have said before, you are more than welcome to bring it in to my shop in Breakwater and we can put it on the bench.
As I have said before, you are more than welcome to bring it in to my shop in Breakwater and we can put it on the bench.
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