Now thats a serious metal detector. I'm really looking forward to the next episode!

Metal detector aside, I think this was the most clear explanation of how AM gets demodulated. I knew the idea behind AM transmissions and saw the single diode demodulator in a lot of radio schematics, but I never noticed the capacitor after it and I never thought about how the actual demodulation is done. Thank you very much for that bit of knowledge!

Crazy how your first prototype is already 10 times more sensitive than the chinese one :)

I've been wanting to understand metal detectors since i was a kid. Thank you for the explanation! Also love that you wind your own transformers. Another piece of magic. Thanks!

I'm glad you've desoldered the buzzer!

when I was in school I made a 3 coil design. it had the coils wound on a piece of 4 inch PVC. the center coil was the driver and the outer two were in series, but connected out of phase. The result was a unit that could separate diamagnetic materials from magnetic materials.

Amazing, I can't wait for the next episode. The sensitivity of your circuit is mutch better than the one from the metal detector I build a while ago. Also I learnd a lot. Have a nice day.

Thank you for making the video. It is very gracious of you. I am glad that you added the audio buzzer. As I understand it, there is an art to using a metal detector and that art is learning what to listen for.

Sometimes you make me think "am I real that stupid"? 😅 Great design and explanation as always!

That is so cool. I'll add it to my 'build it' list.

This circuit is really useful 👍🏻👍🏻

Big fan from India

For audio indication, I would use demodulated voltage and feed it after first or 2nd stage to the 555 set up as an oscillator so it changes the frequency of the tone, also you could use phase comparator section of some PLL IC you have laying around and put 2 LEDs one for ferromagnetic metals and the other one for everything else (at least), it would be a great device capable of beating the pro ones 😜

As always very informative, big thumbs up...

To mitigate the drift of the receiver you can use two low pass filters. One low pass filter for the demodulated waveform and then another one with a much longer time constant to act as an averaging filter. This way you could feed the output of both filters to a comparator and use the average as a reference and the demodulated output as a trigger. So the circuit would become self-calibrating to an extent.

Excellent work, it all made a lot of sense, next episode's gonna be great ...cheers.

Top man !! Real metal detector well explained, described and clear schematic Thank you

Nice Use opamp for first stage of amplifire. Use 2 input inductor for transmiter instead of center tab transformer and put the tx coil directly. Increase inductance of coil and use frq around 7khz. I have designed several digital metal detectors. Vlf metal detectors are simple and really fun

That's actually a really nice solution and circuit. And lots of thought put in ahead of time so there's less trouble later. Initially I winced at the suggestion of an audio alert, but the demonstration looks really useful. I think it's because the detector has to work on changes so the sound will never be a shrill constant annoyance but more like a record scratch. Very nice, looking forward to the next ones!

Very clever receiver/amplifier. I see the changes you made to the receiver coil connections and think I understand the reason.

Love your channel. Your knowledge is priceless my friend. Ty for your time.

Good job. I agree with the pet!

Would love to hear this guy have a conversation with Thoisoi.

Its a very interesting design but I was wondering if you considered using probably one of the oldest metal detection designs. Basically its two LC-oscillators for the same frequency (couple of 100KHz), one has its coil as a large search coil on a wand/stick. The coil of the 2nd oscillator is small and shielded inside the detector housing. The output of the two oscillators is mixed and amplified to headphones. If the two osc. have the same frequency you get nearly no tone but the more the frequency differ even slightly you get a tone with increasing frequency. This happens when the search coil gets into the vicinity of metal because it changes the inductance and therefore the frequency of that osc. If you adjust the freq. to differ just a little so that you hear a steady tone with no metal, you can even detect if the material is ferro-magnetic or not because one will make the tone freq. sink and the other rise.

looks so promising, specially at the end when you showed the audible indicator, which is light-years away better than that crappy buzzer from the chinese board (which thankfully you got rid of!). I really want to know how far it could possibly detect metals and if there's a way to focus the beam (like using some directional antenna radiator optimized for the same frequency); Also, if you increase the sensitivity too much to get metal objects from far distance, does it get interfered by unwanted metals like iron in your blood? 😜

Nice video

Hello, my dear engineer, please make a skeleton so that we amateurs can understand the work, and we can make one from your training.

Very nice job

I build very simmular detector with oscilator and transmitter.I can hear signal from detector on AM radio reciver on middle waves 540-1600kHz

Very nice project and explanations as usual 👍 thank you. 🙏 A dog ?? Where is the cat ? 😂

You should build an fm transmitter... That would be great!

Really good video again. and thank you for removing the buzzer :D

Really nice work! That thing is really sensitive

You are really a genius and you also understand what you construct and are able to explain it to others! Great Job! Magnetic induction and resonance is still a bit of a miracle to me - although i got the general concept :-)

Reinventing a wheel ))) Like, as always.

Niiiiiiiiiiiccccccccccccceeeeeeeeeeeee. =)))))))

new breadboard 😄

Can it detect the metal pins of the circuit components it is made up of

An interesting project. Perhaps a useful addition would be to have the detected imbalance control the amplitude of an audio tone, but then also add a phase comparator that controls the tone frequency. You'd develop a feel for the audio signature of different objects or metals as you sweep across them. A low transmitter frequency (a few kHz) will likely work best when detecting phase shifts.

Love the explanation. Thanks!

That picture you drew looks like me after I smoked something😂

Thank you very much That's a huge work There is a nice schematic using a double 555 timer or a single 556. I tried it my self. But I always have a problem on the winding part

ETI 549 Induction Balance Detector 1977 is good project I built then.

Activate the subtitles so that those of us who do not speak your language can understand you better, so you would have more views !!

LMAO, Great video and coil design. The way you speak reminds me of Forest Gump with an accent. Its hilarious .. Great video man

Wow, things go to interesting side!

thank you dgw. we should build your very good circuit and then go looking for gold or other metals.

Could you please explain the transmitter part in more detail?

Very cool project and practical explanation¡¡. I feel greedy on seeing a more powerful transmitter but i guess it would be worse to tune out

Mechanical adjustment of the coils seems tedious and difficult to implement. I wonder if it would be possible to get them as balanced as possible mechanically and then have a fine adjustment on the transmit power to null out minor variation? Is this a worthless idea?

Вообще можно использовать еще импульсную схему и улавливать отовжение чигналв от объекта, тогда по разности в фазе сигналов можно обнаружить и определить приблизительне расстояние до обьекта.

Please make a better version and schematics for it, so i can make it at myself.

i love your new jokes, always chuckle

Excellent ❤❤❤

would be intersting use operational amplifiers instead of transistors for signal amplification, that could give pretty high sensivity

Now we just need some metal to look out for!

Nice to see the Jack Russel Dog, ;-)

I waiting For your video :)

Awesome! Saving this for later :)

At ~10:40 you describe the clipping limit (rail voltage) of the signal amplitude. So... what if you drive at ~48v or 96v? or even higher (>120)?

Im a fan from 2016

Cat ?

In the third episode you show us how you unearthed the treasure of Priamus .

I have no modicum of doubt that this video will turn out to be impressive. You are indeed great with excellent teaching skill. On a closer look at the receiver circuit, I was persuaded to ask: (1). How would I modify the receiver circuit to achieve a neat AM radio receiver ? (2). Is it possible to also use any of the circuits to build my own analogue TV transmitter ?

Please ,Can i use a diode 1n4148 or 1n4007 to replace the diode 1n5819 for demodulate a signal

Would it be possible to make a stealth metal detector shoe?

This is super cool!

Don't forget that those breadboards have high stray capacitance. You are also waisting 50% of the transmission power, use passive reflector, and parasitic radiator. After all, you are building a radio and antenna. The best discriminater is the human ear, make the output Audio and use Hi-Q headphones. Give some thought to using higher frequencies and superhetrodyne.

fix the coil and You can make a variable transmitter Frequency with a microcontroller To ensure the stability of the signal

Hi I have one question... Is any thing like red mercury tube is invented really??

Good job 👌

Thank you.

hola muy buen proyecto,puede compartir los diagramas y componentes del detector?

ALL metals , have a free electron like the outer most electron of the copper wire. the "free" electron in copper requires less magnetic force to move it, than in other low cost metals. Insulator atoms requires huge, tremendously large magnetic forces to move electrons , hence can create only very tiny miniscule current flow.

Would you try to use a rodin poe as your antena instead?

Here's the dog!

Nice project , is the soil magnetic properties can affect the detector sensitivity and can this detector separate the non ferrous metal .

why not use a PNP, NPN Setup? that way in the later stage u could make the leds turn ON instead of OFF when a metal object distords the field.

Wondering if anyone could help me out. I replicated the circuit but im having problems. The reciever part seems to be working fine, since when i touch the reciever coil input, the led blinks(probably from the 60hz mains interference) but the oscillator circuit seems to not work at all. I did use different transistors but I don't think thats the problem

YAY, you actually built that, i also built it, and found cool stuff with it!! one thing i was looking for is how to make it more powerful ... btw i built the 555 version, i might try your version, looks like it works better :)

Why should it detect onky the ac part of the modulation? Why not let the modulation comes out as frequency (probably like most commercial md)?

You tried to build a metal detector, and made a seismograph as well.

Nice.

Could you make a very sensitive microphone by putting the detector coil on a membrane?

Very nice TY !

That's cool

Interesting as always. But I wouldn't call the metal detector kit a toy, it can be a useful tool if you want to drill a hole in a wall and don't want to hit an electricity or water pipe. Not suitable for the treasure hunt, of course.

Nice 👍✌️🙏

I think there is maybe an error in the transmitter schematic. The value for transformer primary inductance should be probably 0.39 mH, not uH. I simulated this circuit in LTspice and it oscillates on 177kHz, way too high. Also, 0.39 mH at 44 turns would result in AL = 200 nH/turn2 for the transformer core, which is more realistic value.

centimeterssssss

13:51 How crt oscilloscope work with these digital function

Next week it will be a Theremin - lol -.

I would definitely choose a 3D printed coil holder instead of using resin. If it goes wrong, you can change the 3D design and try again. If you use resin then good luck trying to salvage/reuse the coils.

Lm555 and bc327 its not pound we cant other ic and transistor using this circuit please tell me sir this circuit wiring diagram description is your video

u re the best

DGW, your breadboard might not be perfect, but it's probably better than 98% of the ones currently being sold. People with older breadboards are quite fortunate, as the Chinese flood of them for US$1 apiece has made it difficult to do breadboard experiments. The connections on modern Chinese boards are absolute crap. Paying more doesn't necessarily help, either, as most resellers are just getting theirs from China as well. As almost all breadboards look identical, it's nearly impossible to choose a high-quality one. @Everyone: If your parents or other people you know had any sort of electronics background at school or work, ask them if they have an old breadboard that you can have or at least borrow. If stored in good conditions, it will be superior to most of what you will find today.

Good video thanks ;)

Great to see a project that doesn't use a microcontroller.

could the bread board be creating parasitic capacitance that's affecting the over all circuit and the main coil??? P.S. YOUR GETTING THERE! I MEAN IT IS IMPROVING COMPARED TO THE KIT VERSION.. : ) SEE THE NEXT VERSION.. }B=[ >

17:13 and here is the Dog...... *Says nothing about the cool LED display and Nixie Tube Clock*