Great video! Thanks. It might be worth mentioning that whenever one needs to "clip off the connector" from the end of a cable (RCA in this case), it's smart to clip the wire much farther back on the cable (length permitting). By doing that, a second usable cable is created, saving future project cost. Clipping the RCA plug off so close to the end wastes a good opportunity to have a cable for another day.
why collin's series are the best: 1 - he makes everything easy to understand 2 - at the end his prefboards (or whatever he is using) always looks a lot better than mine 3 - he makes funny jokes about stuff while in most of times showing some cool use of something for example, I'm not on guitars or analog electronics circuits but he still makes this video interesting and fun to watch =)
You were probably missing a connection between one of those three bottom resistors. I came across the same problem while making the circuit. It was interesting, to say the least.
Two years late, but... This is because of the type of cable you used between the disk and the rest of the components. The cable he used (an old audio cable) is "shielded", meaning the audio signal won't be influenced by outside sources and won't pick up other signals. If you use standard wires or speaker wire, you have this problem because it doesn't have that shielding. (The shielding happens because the negative "signal" is on the outside.) This is important when buying regular cables for an instrument as well, specifically when you need an instrument cable (which is essentially was made here) versus an amp cable (which is usually not shielded). Source: I've been getting into this recently and needed to learn the difference when purchasing equipment.
Good to know. I'm fairly certain I bought a nearly identical cable for the project, and the interference did go away after I realized I had missed a connection and corrected the circuit. It may have been a combination of the two somehow, though I suppose going back through the project again with new parts and components would show it was the cable all along as you said. Anyways, thanks for the info.
@yhevrah The signal that comes from the Piezo or 'contact mic' is way to small for the amp, so it has to pre-amplified (the signal needs to be made stronger) so that it can be used with a guitar amp. Hope that answers your question.
Also, this video made my day a lot better, it's always nice to hear about interesting projects you can do with electronics; I was looking for some cheap ways to make sounds.
Source and drain are indicated wrong on the diagram. Source is a source of electrons, which are negative, so that one goes towards the ground via the 560 ohm resistor. Drain goes via the 1.5K to the + voltage.
I made one of these minus the preamp and I also added a second disc in parallel so that I could get a more even sound. I place them right behind the bridge, one on either side. I used an 1/8" jack so that I could plug directly into my computer. I think it sounds pretty darn good.
The MPF102 is an N-Channel JFET transistor, try substituting with other N-Channel JFETs. Maybe other MPF transistors, J201, 2N5457? Not to sure how important the transistor specs are in this circuit though? Just check the pinouts on the datasheets and adjust accordingly, to the schematic that is! Should work.
@Snuk1s It'll work the same, although the difference is that the microphone will require an excitation voltage to work (A power source). The amplification will also have to change depending on the voltage range you get back; this means you'd have to modify the choices for R and C.
@pietzeekoe You'd probably need to increase the amplification, not to mention add some filters to eliminate the high frequency noise from external power supplies i.e. 50Hz/60Hz mains.
if there is one thing that always haunts me about electronics is the power wires always snap off my projects...watching this i picked up how to help that...THANK YOU COLLIN
If you were to attach this to a glass pan on a window could you hear what was being said inside the room of that window? Because the soundwaves of the person's voice would strike the window and make it vibrate along with the contact mic?
I think the one thing that would help is a parts list. This video is better because he has them and shows them and the circuit is mostly understandable, but still, thought it was worth mentioning.
FYI - The image shown for the pinout in the MP102 spec sheet appears to be right, but not the diagram to the right that shows the correspondence to the schematic representation.
I have home made stereo contact mics on my desk right now! Perfect for for making duel or stereo sounds. The only thing you did different to me was use epoxy resin which seems a lot better than the hot glue I used. These are so cheap and easy to make and so much fun! :D
Piezoelectricity is really an interesting thing and is found in anorganic, organic and polymeric materials. High impedance output is critical. I experimented with another contact microphone type DIY, but piezoelectric materials are modern and have advantages against other technologies. Therefore I'll test that sort of material too!
I tinkered a bit with piezo microphones to get some kind of pick up for my acoustic guitar. The frequency response is kind of gnarly in piezos... I opted to go for a mini condenser microphone instead. Sounds much better for acoustic guitar.
I didn't even make the amplifier circuit just the piezo and 1/4 jack and I was able to press it against my throat and use it like a mic. If you were to add the amp circuit you most definitely could use it as a throat mic!
Great project idea! Looks like the MPF102 transistors are no longer available, and the nearest thing I could find was a BF245. Tried it and it seems to work. No luck locally (Dallas, TX) finding the 3.3 MOhm resistor. Fry's had a 3 MOhm (well...they had 100 of them that I had to buy, in order to get one of 'em). Put it all together and it worked. However... Did the 3 MOhm sub for the 3.3 MOhm cut down on the volume? Seems I don't get much at all, unless I tap directly on the piezo pickup. I've found I have to have some foam or something else to push the piezo into the wood, in order to get it to detect my foot tapping on the other side of the wood (cigar box). Also, where would I put a volume pot? A tone pot? I'd like to be able to control both from the unit. And if you have any suggestions/experience with pickup placement/box size/etc. as to how it relates to getting the box to sound more like a real base drum, I'd love to know what you know. Thanks, and thanks again for posting this project!
You could use a voltage regulator, but the LM7809 9 volt regulator can take a maximum voltage input of 35 volts, and the LM7824ACT can handle up to 40 volts. Now that's the first option, the second one is buying or making a switch-mode power supply, pololu sells them, not sure what's the maximum input voltage for their switch mode regulator, but I suggest you to take a look on their website.
*Laughts* You are so awsom Collin. its looks like you hiting the big O when you playing and explore thos sounds... and you dont rush true everyting like other How to do shows do.
Can anyone help me out with calculations for above circuit.While calculating Voltage gain i am stuck at calculating gm and Vp.Please help me calculate voltage gain.
Use it as a throat mic? Can you test it and post a quility vid on it? Thanks for all these wondereful ideas. I am thinking about getting MakeMagazene because of these series.
@adequateautocrat Would your throat be able to deform the piezo disc sufficiently for the disc to pick up the sound? Maybe an electret mic would work better.
@dalbeersinghsohal USB might not be able to supply enough power depending on the amplification. I'd recommend looking at an external power source like a battery or rectified mains voltage. You'd have to choose an amplifier which won't attenuate high frequencies.
how good are these. I have brought a few small amp kits similar to this one and wired them up only to find they dont work. are there any tricks when wiring this circuit together so it will work. Thanks all.
Hi! thanks a lot for the tutorial. I have a little question: a have seen other videos and they don´t put any circuit at all. What´s its function is it a preamp? Also, how much is the impedance of the piezo with or without it? Thank you so much!
How would the signal be worse if you would connect the piezo directly to the amp without the circuit? Isn't the high impedance signal of the piezo actually ok for the guitar amp, since the electric guitar pick-ups are also passive? Thank you for answering!
Collin, can you use the contact mike to use it as a neck microphone for a walkie talkie? You know, for when you have to much noise around you to isolate your voice enough...
Good Rockin Out on that Wire Mesh! Growing up, my dad used to play the Rubber Boot. If he'da been able to go electric with it, he coulda been famous! :) Thanks for the info. I'm going make some noise!
This is the only reason I subscribe to Make. What happened to stuff like Weekend Projects? If Collin leaves, you've probably lost hundreds of subscribers. I know I'll be one.
seeing as the piezo element works on vibrations (unlike normal electric guitar pickups), dont you think encasing it in rock hard epoxy might reduce its effectiveness? In other places Ive seen them used (microphones, speakers, triggers, fogers, sonar...) they are never installed with such restrictions. Im no expert here, just using some common sense. I welcome any informed corrections
Nice! I actually made something work :D Thanks Collin! Now I'm trying to replace the battery with a power supply / switching adapter (9VDC, 1A), but I'm getting horrible hum! I've checked the polarity and all grounds are connected (tested with multimeter). Can somene please tell me what's going on?
I have a piezo laying around that I wanted to put in an electric guitar to make it sound like an acoustic (like Parker Fly or Ernie Ball MM guitars), but it was always so damn quiet. now I se that you are using a preamp circuit lol
Sounds light in bass frequencies. Piezo's need a high input impedance, in the many meg ohms, to produce a good sound. I would add a larger input resistor.
+nicethugbert You wouldn't want that on an acoustic guitar though. Most piezo soundboard transducers already output a very high input impedance. Most manufacturers have found that keeping the input impedance of their preamps around 1Mohm is the sweet spot for allowing the best frequency response.
Classic! They sound rad squashed between an electric guitars neck and body in parallel with another single coil too! The output is lower and acts as a high
@megacier try using sparkfuns pocket avr programmer it may simplify things, or the insturcatble/matt richardsons video on how to do it with your arduino
u can use use a stereo jack, connect the battery ground to the ring and the circuits ground to the sleeve, and then the preamp will only be on, pulling power from the battery when the jack cable is connected.
@niceyoungfellow If you put sth. (microcontroller etc.) between the piezo and whatever needs the trigger signal you can do this for sure. There might even be a dedicated IC for a job like this out there.
i have been trying to read up on google how to learn to do stuff like this and get into the basics of circuitry, but i cant seem to find anything good.... maybe im searching wrong, Anyway 1:20 how do u know what stuff to use, is there a site u know of that can help me, like i want to know how u just know which resistors to use and stuff like that, if u can simplify it and give me a site that be cool thanks
it's like learning a new language, when you speak that language long enough, you will know how to say what you think, unfortunetly i have no literature to give you, just find basics of electronics on youtube, I learned from there. I am not sure, but I think that this is basic amplifier circuit using jfet
1. Would a typical electric guitar patch cord substitute for the RCA cable? 2. for the 1/4 inch jack, is mono or stereo needed? I have a stereo one and I heard you can use it for mono.. is this true? Thanks
how does the transistor amplify the piezo circuit? I am just an electronics nube, but the sound from the comb couldnt have been producing more than a few tens of millivolts in the piezo and the FET requires a couple volts at the gate to activate, right? Could someone clear this up for me please?
I love this show. I've learned lot from him. Lot of memories watching this after many years.
The sounds from the wire mesh were pretty amazing!!
Great video! Thanks. It might be worth mentioning that whenever one needs to "clip off the connector" from the end of a cable (RCA in this case), it's smart to clip the wire much farther back on the cable (length permitting). By doing that, a second usable cable is created, saving future project cost. Clipping the RCA plug off so close to the end wastes a good opportunity to have a cable for another day.
Why are there no more Collin videos these days? He was the only reason I watched!
They are now on Adafruit.
why collin's series are the best:
1 - he makes everything easy to understand
2 - at the end his prefboards (or whatever he is using) always looks a lot better than mine
3 - he makes funny jokes about stuff while in most of times showing some cool use of something
for example, I'm not on guitars or analog electronics circuits but he still makes this video interesting and fun to watch =)
Honestly, this is the best Collin's Lab video yet, because he just gave me the key I needed to fulfill my one-man-band dream!
THANKS COLLIN! YOUDAMAN!
7:33 Has science gone too far?
yes. yes it has
So I made it and my guitar is picking up radio signals... I'm currently listening to the radio. I think I did something wrong
Frankie Romero lol
You were probably missing a connection between one of those three bottom resistors. I came across the same problem while making the circuit. It was interesting, to say the least.
Two years late, but...
This is because of the type of cable you used between the disk and the rest of the components. The cable he used (an old audio cable) is "shielded", meaning the audio signal won't be influenced by outside sources and won't pick up other signals. If you use standard wires or speaker wire, you have this problem because it doesn't have that shielding. (The shielding happens because the negative "signal" is on the outside.)
This is important when buying regular cables for an instrument as well, specifically when you need an instrument cable (which is essentially was made here) versus an amp cable (which is usually not shielded).
Source: I've been getting into this recently and needed to learn the difference when purchasing equipment.
Good to know. I'm fairly certain I bought a nearly identical cable for the project, and the interference did go away after I realized I had missed a connection and corrected the circuit. It may have been a combination of the two somehow, though I suppose going back through the project again with new parts and components would show it was the cable all along as you said. Anyways, thanks for the info.
Can i shield the audio cable with aluminum foil? Will it work?
This guy is a legend
Collin as always you made my day. I am so happy you're making your videos, please don't stop.
Collin, you are the best DIYer I've ever seen
You are the only reason I'be subscribed to MakeMagazine :D
oh, come one now. what are you doing with a comb??
@yhevrah The signal that comes from the Piezo or 'contact mic' is way to small for the amp, so it has to pre-amplified (the signal needs to be made stronger) so that it can be used with a guitar amp. Hope that answers your question.
Collin's Lab is the reason why I subscribed to makemagazine. You are awesome-o Collin-o!
What a great demonstration! Fun and educational at the same time!
Will you please get your own channel I could watch you talk about electronics all day even on things I already know you are a good teacher.
Also, this video made my day a lot better, it's always nice to hear about interesting projects you can do with electronics; I was looking for some cheap ways to make sounds.
Source and drain are indicated wrong on the diagram. Source is a source of electrons, which are negative, so that one goes towards the ground via the 560 ohm resistor. Drain goes via the 1.5K to the + voltage.
qual a solução?
Works great inside of my 12 string guitar! I don't know if I got lucky, but it sounds really full and there is zero noise.
The fact that colin can play guitar only adds to his awesomeness
collins lab is the only reason im still subscribed, i can ignore the other girl and guy in order to occasionally get something good from collin. :)
what is the difference between types of transitor, i couldn't find mtf102 in my area, can i use another types
I made one of these minus the preamp and I also added a second disc in parallel so that I could get a more even sound. I place them right behind the bridge, one on either side. I used an 1/8" jack so that I could plug directly into my computer. I think it sounds pretty darn good.
The MPF102 is an N-Channel JFET transistor, try substituting with other N-Channel JFETs. Maybe other MPF transistors, J201, 2N5457?
Not to sure how important the transistor specs are in this circuit though? Just check the pinouts on the datasheets and adjust accordingly, to the schematic that is!
Should work.
The source and drain were reversed in your instructions. The drain goes towards +Vcc and source goes to ground. Works much better.
Então como fica no esquematico!!???
@Snuk1s It'll work the same, although the difference is that the microphone will require an excitation voltage to work (A power source). The amplification will also have to change depending on the voltage range you get back; this means you'd have to modify the choices for R and C.
That comb sounded terrific!
As long as there is no mac, these videos are great.
This is the most inspired circuit I've ever been itching to try!!
considering the fact that you're running an acoustic guitar through what looks like an electric guitar amp, that sounds really good.
Man, you're cool!!
Wondering, could you have used the piezo crystals you created to make this "sensor"?
@pietzeekoe You'd probably need to increase the amplification, not to mention add some filters to eliminate the high frequency noise from external power supplies i.e. 50Hz/60Hz mains.
if there is one thing that always haunts me about electronics is the power wires always snap off my projects...watching this i picked up how to help that...THANK YOU COLLIN
It's always my master peace to learn electronic component. Please keep on!
You are a genius! amazing idea with piezo plate
DIY Electroencephalograph! We need that
I fed the signal from the piezo right into my guitar amplifierer. Works just fine. No pre-amp circuit needed
I can't find the MPF102 anymore, what can I use as a substitute? Will a J113 work?
Nice to see the perf board in action vs. jumpers all over the place.
@nThanksForAllTheFish You are right. However, the MPF102 is a symmetrical FET and this can be reversed. Not all FETs are reversible.
If you were to attach this to a glass pan on a window could you hear what was being said inside the room of that window? Because the soundwaves of the person's voice would strike the window and make it vibrate along with the contact mic?
collin is the best teacher ever!
I think the one thing that would help is a parts list. This video is better because he has them and shows them and the circuit is mostly understandable, but still, thought it was worth mentioning.
FYI - The image shown for the pinout in the MP102 spec sheet appears to be right, but not the diagram to the right that shows the correspondence to the schematic representation.
Estou tendo esse mesmo problema!!
The tip (center pin of the rca plug) is hot & the surrounding shielded wire (sleeve) is your ground or negative wire.
Can i replace mpf102 to 2SK30A mosfet?
I have home made stereo contact mics on my desk right now! Perfect for for making duel or stereo sounds. The only thing you did different to me was use epoxy resin which seems a lot better than the hot glue I used.
These are so cheap and easy to make and so much fun! :D
Piezoelectricity is really an interesting thing and is found in anorganic, organic and polymeric materials. High impedance output is critical. I experimented with another contact microphone type DIY, but piezoelectric materials are modern and have advantages against other technologies. Therefore I'll test that sort of material too!
I tinkered a bit with piezo microphones to get some kind of pick up for my acoustic guitar. The frequency response is kind of gnarly in piezos... I opted to go for a mini condenser microphone instead. Sounds much better for acoustic guitar.
Man .. You are awesome
... Very clear , easy and not least important , FUN tutorial.
I didn't even make the amplifier circuit just the piezo and 1/4 jack and I was able to press it against my throat and use it like a mic. If you were to add the amp circuit you most definitely could use it as a throat mic!
Hey Collin, I just LOVE your videos. I can't wait to try this out and maybe get my daughters accoustic guitar amplified so she can play Rocksmith !!
Hey Collin. It´s great. But you can do this much easyer just puting a cable to the piezo if you are going to use an amplifier! Thanks for the info!
Great project idea! Looks like the MPF102 transistors are no longer available, and the nearest thing I could find was a BF245. Tried it and it seems to work. No luck locally (Dallas, TX) finding the 3.3 MOhm resistor. Fry's had a 3 MOhm (well...they had 100 of them that I had to buy, in order to get one of 'em). Put it all together and it worked. However...
Did the 3 MOhm sub for the 3.3 MOhm cut down on the volume? Seems I don't get much at all, unless I tap directly on the piezo pickup. I've found I have to have some foam or something else to push the piezo into the wood, in order to get it to detect my foot tapping on the other side of the wood (cigar box).
Also, where would I put a volume pot? A tone pot? I'd like to be able to control both from the unit. And if you have any suggestions/experience with pickup placement/box size/etc. as to how it relates to getting the box to sound more like a real base drum, I'd love to know what you know.
Thanks, and thanks again for posting this project!
Olá @brad, como consegui, pois eu não consegui, trocar o transistor bf 245, sem acerto para algum resultado, me de uma mão, para construi-lo
You could use a voltage regulator, but the LM7809 9 volt regulator can take a maximum voltage input of 35 volts, and the LM7824ACT can handle up to 40 volts.
Now that's the first option, the second one is buying or making a switch-mode power supply, pololu sells them, not sure what's the maximum input voltage for their switch mode regulator, but I suggest you to take a look on their website.
*Laughts* You are so awsom Collin. its looks like you hiting the big O when you playing and explore thos sounds... and you dont rush true everyting like other How to do shows do.
Can anyone help me out with calculations for above circuit.While calculating Voltage gain i am stuck at calculating gm and Vp.Please help me calculate voltage gain.
I tried this a while back with no pre-amp...no luck. I'll have to give this a go.
Use it as a throat mic? Can you test it and post a quility vid on it? Thanks for all these wondereful ideas. I am thinking about getting MakeMagazene because of these series.
@adequateautocrat Would your throat be able to deform the piezo disc sufficiently for the disc to pick up the sound? Maybe an electret mic would work better.
@dalbeersinghsohal USB might not be able to supply enough power depending on the amplification. I'd recommend looking at an external power source like a battery or rectified mains voltage. You'd have to choose an amplifier which won't attenuate high frequencies.
how good are these. I have brought a few small amp kits similar to this one and wired them up only to find they dont work.
are there any tricks when wiring this circuit together so it will work. Thanks all.
One of the most interesting projects on here!!
Hi! thanks a lot for the tutorial. I have a little question: a have seen other videos and they don´t put any circuit at all. What´s its function is it a preamp? Also, how much is the impedance of the piezo with or without it? Thank you so much!
+Pablo Martín Yes, the transistor works as an amplifier, without the circuit the output would definitely sound lower in volume.
Would I have to use different resistor values if I chose a different power source, say 11.1 volts?
Cool as always Collin. Great stuff.
A while ago I tore apart some old multimeters with piezos in them and converted them into drum triggers for my DM5. Fun stuff.
could you place it on a sheet of glass (like a window) and have it amplify the sound waves the glass picks up?
This is really great! Worked excellent for my needs! :) Thanks Collin!
How would the signal be worse if you would connect the piezo directly to the amp without the circuit?
Isn't the high impedance signal of the piezo actually ok for the guitar amp, since the electric guitar pick-ups are also passive? Thank you for answering!
Collin: the NEW, more tech savvy, Kip Kay [and now with a serene voice!]
i love this guy, all his videos are entertaining and very useful
6:13 , how to create distortion in sound just like Electric guitar using circuit and normal music amplifier
Can the output just light up an led? I wanted to just build a sound sensor that just flashes when ever the is sound
Collin, can you use the contact mike to use it as a neck microphone for a walkie talkie? You know, for when you have to much noise around you to isolate your voice enough...
Best part, your acoustic playing. Nice rhythm.
Good Rockin Out on that Wire Mesh!
Growing up, my dad used to play the Rubber Boot. If he'da been able to go electric with it, he coulda been famous! :)
Thanks for the info. I'm going make some noise!
This is the only reason I subscribe to Make. What happened to stuff like Weekend Projects? If Collin leaves, you've probably lost hundreds of subscribers. I know I'll be one.
Nice video, but why use a transistor amp instead of a neatly packaged amplifier IC like an LM386?
seeing as the piezo element works on vibrations (unlike normal electric guitar pickups), dont you think encasing it in rock hard epoxy might reduce its effectiveness? In other places Ive seen them used (microphones, speakers, triggers, fogers, sonar...) they are never installed with such restrictions. Im no expert here, just using some common sense. I welcome any informed corrections
Where did Collin Go???? He was the whole reason I subbed makemag. :(
If I were to make this with a 2.5mm line out instead of the 3.55 mm stereo jack, would this work to make a throat mic?
Nice! I actually made something work :D Thanks Collin!
Now I'm trying to replace the battery with a power supply / switching adapter (9VDC, 1A), but I'm getting horrible hum!
I've checked the polarity and all grounds are connected (tested with multimeter).
Can somene please tell me what's going on?
eu , tenho o mesmo problema , tambem não achei, de onde vem o zumbido , eu o mau não funcionou , tambee, quero uma ajuda!1
I have a piezo laying around that I wanted to put in an electric guitar to make it sound like an acoustic (like Parker Fly or Ernie Ball MM guitars), but it was always so damn quiet. now I se that you are using a preamp circuit lol
it can also be used as a piezo tweeter :)
Sounds light in bass frequencies. Piezo's need a high input impedance, in the many meg ohms, to produce a good sound. I would add a larger input resistor.
+nicethugbert I'm going to test that out as I want to try and use this for my acoustic bass guitar. thanks for the info
+nicethugbert You wouldn't want that on an acoustic guitar though. Most piezo soundboard transducers already output a very high input impedance. Most manufacturers have found that keeping the input impedance of their preamps around 1Mohm is the sweet spot for allowing the best frequency response.
TOCS I did this on my acoustic and it sounds so great I did it on my brothers acoustic bass guitar
John Strauss
You tried various input impedances? Which input impedance did you find the most pleasant after experimenting?
No I did what Collin did and it work out great for me on both Acoustics I did it on.
Classic! They sound rad squashed between an electric guitars neck and body in parallel with another single coil too! The output is lower and acts as a high
@megacier try using sparkfuns pocket avr programmer it may simplify things, or the insturcatble/matt richardsons video on how to do it with your arduino
u can use use a stereo jack, connect the battery ground to the ring and the circuits ground to the sleeve, and then the preamp will only be on, pulling power from the battery when the jack cable is connected.
Do u have a video on how to build a led cube or if u can make one
@niceyoungfellow If you put sth. (microcontroller etc.) between the piezo and whatever needs the trigger signal you can do this for sure. There might even be a dedicated IC for a job like this out there.
i have been trying to read up on google how to learn to do stuff like this and get into the basics of circuitry, but i cant seem to find anything good.... maybe im searching wrong,
Anyway 1:20 how do u know what stuff to use, is there a site u know of that can help me, like i want to know how u just know which resistors to use and stuff like that, if u can simplify it and give me a site that be cool thanks
it's like learning a new language, when you speak that language long enough, you will know how to say what you think, unfortunetly i have no literature to give you, just find basics of electronics on youtube, I learned from there.
I am not sure, but I think that this is basic amplifier circuit using jfet
1. Would a typical electric guitar patch cord substitute for the RCA cable?
2. for the 1/4 inch jack, is mono or stereo needed? I have a stereo one and I heard you can use it for mono.. is this true?
Thanks
Output is better with the prea-amp then without, but still the signal is quite weak, can the circuit be easily adapted to amplify a bit more?
Please bring back Collins Lab D:
I want moar episodes/videos D:
I've been trying to find a way to make my own pickup! This is awesome! Just what I was looking for!
is the circuit necessary???? because ive seen videos where they just hook it up to wire and the amp and it works fine.
Can i use bjt instead fet or mosfet ?
how does the transistor amplify the piezo circuit? I am just an electronics nube, but the sound from the comb couldnt have been producing more than a few tens of millivolts in the piezo and the FET requires a couple volts at the gate to activate, right? Could someone clear this up for me please?
Could a potenciometer and a switch be added to the squematic?