Step 5: Tune It Up!!!!

Now that everything had been installed onto the body and the detector now looks more like somethign is time for the finishing touches. turn it on and listen for noise. Then screw the screw into the canister slowly and listen for change. If the tone goes higger, you are good. If you put it all in and nothing changes, you need more metal. One way to test this is to shove a big piece of metal inside the pick up coil, if you see a change and in some point beeping then you need more metal. IF it gets worse, then you have too much inductance, and the search coil is under inductance. try adding some screws to the detector plywood boddy. you have to get both inductors at same frequecy. with mine i needed more metal inside my pick up, and what i discovered is that metal close to the coils will change it more than in the midle of the canister ( like the screw). So now get those washers and nuts and put them inside the canister. Push them in until you get the sweet spot. then get some superglue and glue them there. this will add a lot of induction to your coil. then use the small screw to adjust it tight.

There's a lot of playing arround in this area, the better you make thigns the better they will work. IF the screw is too loose then it will go in and out of frequency all the time, this hapened to me and i'm in the process of re-engineering it. hoep it helps sned any Questions I'll try to help.
Hello,<br>I was planning on making one such metal detector. What I want id to search for coins in my garden(lets say) , to what depth would I be able to find these coins? Or, what would be best approach to achieve similar result on low budget?
<p>i dont get why my speaker makes no sound. 2coils seems to work according to multimeter reading. </p><p>Then <br> i made another circuit on prototypeboard and search coil didnt <br>oscillate. When i poked transistors and some resistors a bit then <br>speaker buzzed a bit and multimeter gave hz reading. But after some <br>playing around like that it went quiet too. And search coil still not <br>oscillating.</p><p>i'm using polyester capacitors. Why my capacitors same value came white boxed caps not like yours i dno, what the difference</p>
<p>Capacitors comes in many shapes and forms, that shouldn't make any difference as long as the farad value is the same and the voltage capacity is high enough. You say you use polyester caps and that is fine for the small ones, but they do not exist for 220uf caps, so you need electrolytic ones for this.</p><p>The components have a certain margin of error that may cause the problem? I'm not familiar with the circuit and there are no potentiometers, so there is no easy way to finetune it the way it is now as i can see, but i'm far from an expert. If i'm right the 0.01uf caps and the 39K resistors are the ones that generates the oscillation frequency.</p><p>I'd try to switch the 39K resistors with variable resistors and finetune them a bit to see if that helps.</p><p>I don't want to be a pessimist here, but i'm pretty shure this is not the circuit to go for if you want to make a detector for serious hunting. There are most definately a lot of better choices out there.</p>
<p>I found a lot of stuff with this detector :D After getting some experience with electornics i decided to make tesoro golden sabre. Very good and stable, added fm transmitter for wireless headphones :D Using litium batteries and made charger also for them. https://www.youtube.com/watch?v=YDDo7g47T1g 1 euro coin max is 30cm air depth. Doesnt differ much from ground depth. Now i'm making my own cnc mill as next project :D Ty for answering anyways.</p>
<p>Can it detect GOLD ?</p><p>PLease reply ~</p>
<p>It can if it works, but only if the nugget is big enough, close to the surface and if there is no other metals around. Short answer is: No.</p>
<p>Can someone please tell me if this detector can be used in gold prospecting....plz</p>
<p>Don't even consider it, it's definately a waste of time if you want to find gold with it. </p><p>Gold nuggets are hard enough to find with expensive metal detectors, with this detector it is maybe possible to find the gold ring you just lost in a sandbox.</p>
Like so!
Nice thanks.. Would it be a bit more of a weight reduction if you simply cut a circle out of the middle, then out of the scrap a cross beam you can just screw in place with a metal bracket if you need it? I figure a one inch rim, with the middle empty may be enough to still mount everything needed?
<p>i dont get why my speaker makes no sound. 2coils seems to work according to multimeter reading. </p><p>Then <br> i made another circuit on prototypeboard and search coil didnt <br>oscillate. When i poked transistors and some resistors a bit then <br>speaker buzzed a bit and multimeter gave hz reading. But after some <br>playing around like that it went quiet too. And search coil still not <br>oscillating.</p><p>i'm using polyester capacitors. You are not as i can see?</p>
<p>Ne fonctionne pas !</p><p>Does not work!</p><p>it is possible to have a photo of the plate, and complete description ? Thank you . Contact Me alexandreladra660 (at) hotmail.com</p><p>I am French , I use a translator.</p><p>Doc !</p>
<p>magnific, please contac me to jonath55@hotmail.com</p>
<p>plz help me idid but it seems not working!ive checked the schematic but it was right i test the transistor it was ok and the capacitor.i use a 2n2222a/ksp2222a pls help me why i did not work! pls answer me fast</p>
<p>one question....detect gold?</p>
Wow, brilliant job! you just made it. How many bulks you paid for your home made <a href="http://www.detectorall.com/" rel="nofollow">metal detector</a>?
How thin or thick was your coils? And how many rings did you make with it as well ?
its work but when i use large coil (60x30 cm) its detect just 20 cm or less for large object what i make wrong ???? cau help me plz
I have no idea what you may be doing wrong, too high frequency, or very low inductance may be your problem, it decreases the magnetic field growth. decrease the turns in both coils, or increase them? I'm no expert, good luck.
i made every thing but resistor 0.5 watt and 2.2mega 1 watt and when i make test the sound i have just esh sound and there is no change so what wrong i made ???
the wattage doesnt matter. if you hear static sound then its working. try to insert many metal objects into the small inductor, see if it makes it better, if not, remove everything of metal from the litle inductor then add metal to the big coil on the ground. find a way to make them the same. good luck
its work but when i use large coil (60x30 cm) its detect just 20 cm or less for large object what i make wrong ???? can u help me plz
I have tried mutiple times to build this with no luck, have used both circuit designs. All I get is a clicking sound when I first turn it on, then nothing else. <br>Any ideas what I might be doing wrong?
There is no way to tell, if you are using ONE, just ONE item that is different, that could make all the difference. Do you hear static? it could be that the frequencies are way off. maybe you are wiring it wrong. without me being able to look at the circuit in my hand, there is little to nothing I can do.
hello ... I really liked your article and I would like to know how I can modify it to find metal but 10 or more meters away, thanks
Your not going to build that your self, that would be impossible <br>
maybe increase the voltage, thus increasing the magnetic field. but beware resistors may need to be bigger, and so on.
im going to make one! i should have most of the components in my &quot;parts box&quot; lol<br> thanks!! for clarify some things the other site was weird....<br> i was wondering why you use &quot;off&quot; in the parts list?<br> why not use x instead lol<br> (2 off 220uF 16v electrolytic) (2x 220uF 16v electrolytic)<br> i took an electronics class for 2 years (2hours 30min a day) when i was in high school and never seen a parts list with &quot;off&quot; describing how many you need...<br> people dont just go around saying &quot;i need 3 off loaves of bread&quot; or<br> &quot; 2 off cans of beans&quot; lol...<br> off is describing if something is on or not lol.....<br> people also dont say i want 5x oreos 1x cup of milk lol<br> off just didn't make sense when used in the parts list<br> even if you got the list from the other site i would of fixed it. lol<br> (sorry im not trying to be rude or anything)<br> (lol electronics class was the highlight of my day any other class and im bored to death)....................
off is how engineers describe parts lists.<br>I know, i am an engineer
What type of engineer are you the word off means not on, like light is on or off, if you want to say you have resistors you use of not with a double f <br>
Thank you Captain Proper Gramar!<br>
Its Grammar Nazi btw
lol i was just saying.......<br> <br> so what have you found so far with your metal detector?<br> im sure everyone else is curious if you found anything with this home made metal detector.
I've barely used it, it was fort a college presentation on oscillating circuits. <br><br>I used it to find a spoon the professor buried to see if it worked. I used to find come screws i lost while working on a motorcycle in the grass. I may upgrade it since I'm now working making mine detectors for the military and they use metal detectors as well as Ground Radar.
nice good luck
hello if we have to increase the range say fing any metal upto 3ft then wat hv to do?
higuer voltage would do this, but you need to watch for the transistor's power dispation, and the resistors too. I dont know the answer to that Q.
I would like to make a metal detector for finding nails etc. in wood, so I want to be able to find small objects but also within a short distance. Can you say something about how to modify your project in order to accomplish this?
then you want a very small inductor at the bottom, whatever diameter you see fit. Maybe Two medicine bottles, with same windings, should match themselves easily. then move the pill container around the wood. if I'm not mistaken, higher frequency is less current on the coil which means better battery life, less flux around the core, so its more directional and precise. Thats is all a guess. good luck.
hi,, its it we have to match both of the inductance value ,, then only it will works? if thats so,, <br><br> can i have your inductance value of both coil,, coz i dont have anameled with 26 AWG of diameter ,, i just have 0.2mm.. i will try to match your value with this diameter wire of mine,, pleeeeeeeeeeeeeeez reply me,, TQ =)<br>
You can use whatever wire you want. Just got to calculate the inductance of both and they have to match. Use online calculators, look for &quot; air core inductor calculator&quot; and you use the size of wire, diameter and turns, and you can get in the ball park, use the screw to fine tune them.
thank you sooooooooooooooooooo much
SIR, <br> can i use any other ic instead of cs209a n making single chip metal detecter.
Hi Joel I am a amateur at this but I Have built this circuit 3 times now and cant git the speaker to make a sound I used all new parts when I built it each time.<br>Just don't know what I'm doing wrong. Can You explain whats happening in this circuit so that I can trouble shoot it better. All so I used the NPN 4011 and was wondering if there are different values of the same transistor or some thing.<br>Any help will be greatly appreciated.
Every single transistor has different values, and so minor tweaks may be need. It seems the Transistor you are using is WAY too old, and it was difficult to even find the Datasheet for it. Its also very high frequency and low gain. to drive the speakers you need high gain. <br> <br>Try a 2n2222 or a 2n3904 transistors, easy to find anywhere. <br> <br>I already explained what goes on in this circuit. The top small Capacitor-Inductor (LC) oscillates at the same frequency as the bottom LC circuit. They cancel each other out, when metal aproaches the bottom inductor, it changes the freq, and that difference peak pulse is aplified from left to right, trough each transistor, then to the speaker.
Can you replace the audio output with a visual signal? (small bulb / led / etc.)
You could but i dont know hwere exactly, i would suggest on the Collector of Q4 and ground
Hi,<br>thanks for this instructable. Can I use this method to make a security system like those we see in airports, those which look like doors that passengers pass to have been checked.
yeah you would have to make people pass trough the inductor at the bottom basically. match the inductance of each, make the bottom one a circle 6 ft in diameter. you can bend the circle into a square. you can also use the inductor on the side panels of the &quot;door way&quot; where people walk trough and make it oval so it covers the whole door area, doesnt have to be perfectly cicular.
thank you very much

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