The layout of the LM358 on the breadboard is completely fouled.

The way you inserted the chip, pin 1 is shorted to pin 8, 2-7, 3-6 and 4-5. Imagine you V+ is on pin 8, your output of the op-amp is directly connected to V+.

Besides, the V+ should go to Pin 8 not Pin 1. The black wire should go to pin 4 not pin 3.

Shift the LM358 down by 3 holes and it'll be OK.

Allen

Hey,
Is it right this time?Any suggestion?
http://forum.allaboutcircuits.com/attachment.php?attachmentid=69699&stc=1&thumb=1&d=1402549340

 

Hello ScottWang,
I've done it again. Please check and tell me if its right or wrong. Also do we need to provide power supply to this circuit and then will it go to the pc keyboard's keys?Do we need to provide power supply to each piezo we use?

Thanks.

I'm not sure why you want to use LM386, in this case, you just using the LM324 or similar op amp is ok, the voltage gain of LM386 maybe not enough for the piezo amplifying, at least not for mine, the LM324 op amp and the LM386 audio amplifier, they designed for different purpose, if you want to use it, then you have to try it by yourself.

Almost the circuit need the power, otherwise the circuit won't work.

LM324 datasheet NS.

 

I'm not sure why you want to use LM386, in this case, you just using the LM324 or similar op amp is ok, the voltage gain of LM386 maybe not enough for the piezo amplifying, at least not for mine, the LM324 op amp and the LM386 audio amplifier, they designed for different purpose, if you want to use it, then you have to try it by yourself.

Almost the circuit need the power, otherwise the circuit won't work.

LM324 datasheet NS.

Hey ScottWang,
The pictograph was for representation purpose only. ! I didnt get the right IC image,thats why it happened.I'll use the LM324 itself for building the circuit. I asked you to clarify whether is this the way to do the connection via the schematics provided by you. In that case is this right.???

 

Hey ScottWang,
The pictograph was for representation purpose only. ! I didnt get the right IC image,thats why it happened.I'll use the LM324 itself for building the circuit. I asked you to clarify whether is this the way to do the connection via the schematics provided by you. In that case is this right.???

As the LM358 pictograph that you attached, I will say that again, please don't connecting the output of op amp to the +V and GND of breadboard, you have to find some position to connect the output, otherwise you may blow up the op amp or some other EE parts in the real world someday.

Except the above problem then the connections are ok.

When you used the different parts with the pictograph or some attached then you have to described it.

 

As the LM358 pictograph that you attached, I will say that again, please don't connecting the output of op amp to the +V and GND of breadboard, you have to find some position to connect the output, otherwise you may blow up the op amp or some other EE parts in the real world someday.

Except the above problem then the connections are ok.

When you used the different parts with the pictograph or some attached then you have to described it.

Hey,
Now tell me which of the attached picture is right? #1 or #2? Or are both of them wrong?
The transistor used is for representation purpose only.

 

Hey,
Now tell me which of the attached picture is right? #1 or #2? Or are both of them wrong?
The transistor used is for representation purpose only.

What's the internal structures of keyboard#1,#2?

 

What's the internal structures of keyboard#1,#2?

I mean that, as a keyboard is a set of contact switches, Connection#1 is the first wire of a key and connection#2 is the second wire of the same key.I want these two wires of a specific key to short to get a drum sound. Suppose the two wires of key 'B' shorts,It will make the sound of bass drum. And like this for a whole drumkit.
Hope you understood. Now say,which one is the right image??????????
PS-The IC & battery is for representation only.

 

I mean that, as a keyboard is a set of contact switches, Connection#1 is the first wire of a key and connection#2 is the second wire of the same key.I want these two wires of a specific key to short to get a drum sound. Suppose the two wires of key 'B' shorts,It will make the sound of bass drum. And like this for a whole drumkit.
Hope you understood. Now say,which one is the right image??????????
PS-The IC & battery is for representation only.

If you wish to use the piezo buz to be the input components, then they will be in stead of the switches or keys, when you hit the piezo buz, it will send the signal to the op amp, and the op amp will output a high voltage signal, then you can using the high signal to trigger other devices such as EE drums.

 

If you wish to use the piezo buz to be the input components, then they will be in stead of the switches or keys, when you hit the piezo buz, it will send the signal to the op amp, and the op amp will output a high voltage signal, then you can using the high signal to trigger other devices such as EE drums.

So which of the provided images is the right one ?????
According to the circuit you have provided, will the piezo act as a trigger switch instead of a key/switch of the keyboard ????

 

So which of the provided images is the right one ?????
According to the circuit you have provided, will the piezo act as a trigger switch instead of a key/switch of the keyboard ????

The piezo buz active as a spring not like the normally switch, the reflection just similar as the surface of drum, so using piezo buz is better then the switch, I mean that as spring is to describe the voltage amplitude of piezo buz, but the switch can't reach that function.

 

The piezo buz active as a spring not like the normally switch, the reflection just similar as the surface of drum, so using piezo buz is better then the switch, I mean that as spring is to describe the voltage amplitude of piezo buz, but the switch can't reach that function.

Hey friend,
You have'nt still mentioned whether which of the two images are the right one?
Also, do you have any working video of the circuit you've made with the LM324???

 

Hey friend,
You have'nt still mentioned whether which of the two images are the right one?
Also, do you have any working video of the circuit you've made with the LM324???

I don't have the video, but I saw the LED of two circuits that they working just like the video you linked, I already separated the 2SK30 and the npn bjt circuit.

 

If the drum project is not independent from computer, then they should be have the software to analyze the input signal, so now you can draw the all idea with whole block you want the drum to work, and then it' will be more easy to discuss.

 

If the drum project is not independent from computer, then they should be have the software to analyze the input signal, so now you can draw the all idea with whole block you want the drum to work, and then it' will be more easy to discuss.

Yeah, I'm using a free software called DvDrums.
We'll discuss.Lt me plan something.

 

If the drum project is not independent from computer, then they should be have the software to analyze the input signal, so now you can draw the all idea with whole block you want the drum to work, and then it' will be more easy to discuss.

But I have a question.
Is the current in a keyboard's single key enough to complete the circuit you've provided for a single piezo? Or do I need to provide external power supply.?????

 

But I have a question.
Is the current in a keyboard's single key enough to complete the circuit you've provided for a single piezo? Or do I need to provide external power supply.?????

You can get the power from USB +5v and GND, it's enough for the op amp to use. (buy a USB expanding cable, and an USB male plug)

How may pieces of piezo buzs you need, it depends on how many input key you want.

 

You can get the power from USB +5v and GND, it's enough for the op amp to use. (buy a USB expanding cable, and an USB male plug)

How may pieces of piezo buzs you need, it depends on how many input key you want.

I want to use a total of 12 piezo for the 12 inputs. Will the USB handle the power supply or should I provide external power supply?Is yes how much?

 

I want to use a total of 12 piezo for the 12 inputs. Will the USB handle the power supply or should I provide external power supply?Is yes how much?

There are many kinds of USB cable, I suggest the type as this.

wikimedia USB knowledge.

The USB pinout as :

The USB male plug as:

Computer USB +5V female plug → male plug, USB cable, female plug → USB male plug, op amp Power.

 

There are many kinds of USB cable, I suggest the type as this.

wikimedia USB knowledge.

The USB pinout as :

The USB male plug as:

Computer USB +5V female plug → male plug, USB cable, female plug → USB male plug, op amp Power.

Hey, Please wait patiently for the discussion because my exams are coming up, so I cant sit on the computer always.
But I've tried the circuit you've provided on a breadboard, but it just lights straight away when connected,and it doesnt makes any use of the piezo. What can be the problem??? Also, I've attached another pic which i simply tried with LM324.Its 1,2,3 pins are connected and followed to a 4.7K trim pot. It lights when the piezo is hit,but a full current doesnot passes through it. . The LED shows a partial blink. What do you say?

 

Hey, Please wait patiently for the discussion because my exams are coming up, so I cant sit on the computer always.
But I've tried the circuit you've provided on a breadboard, but it just lights straight away when connected,and it doesnt makes any use of the piezo. What can be the problem??? Also, I've attached another pic which i simply tried with LM324.Its 1,2,3 pins are connected and followed to a 4.7K trim pot. It lights when the piezo is hit,but a full current doesnot passes through it. . The LED shows a partial blink. What do you say?

You didn't provide the power for the LM324, pin 11 connecting to GND, and the pin 4 connecting to +Vcc.

GND for the battery negative, and the +Vcc for the battery positive.

LM324 datasheet.

I have something important, Tomorrow need to back to the country side, so it may not easy to get online, I will still to try if I could.