I just now found out that i have to build an audio oscillator of some fixed frequency and these microprocessors and complicated circuits are not allowed. i have to build a musical instrument with three audio oscillators of different frequencies.
By pressing one switch one oscillator should produce a sound, and by pressing other switch the another oscillator should produce the sound.

Can u please help me and tell me how to build an audio oscillator of a frequency say 261.63 Hz (which is the frequency of musical note C)?

 

I'd go with the 555, and the 4017. The 4017 is a simple sequencer, the 555 will do everything else (you'll need more than one).

Start simple. Look up the 4017, I have several example how to use it to power an LED in my LEDs, 555s, Flashers, and Light Chasers. Instead of powering an LED, either power a CMOS 555 oscillator tuned to the note you want, or use the 4017 to change a component that is common to a 555 oscillator.

Google, 555 organ.

 

Just read your last post, look up this article that I wrote...

555 Hysteretic Oscillator

 

I m not allowed to use such ICs, like 555 and all, my professor says, it becomes complicated. and so i am also not allowed to design such IC in my circuit on my own. so is there any other way?

 

A 555 is not complicated, but for us to even begin to help you need to tell us what you are allowed to use. Otherwise my suggestion is a whistle (we are not mind readers, and you set the conditions).

Just curious, did you even look at the article?

 

Yes man, i looked at the article. I had shown that 555 and 4017 liike similar things (I dont evn know wt they r called) from one of the mentioned circuits in this thread, to the professor , and he said you are not allowed to use these things, its complicated, and i can not use any programming.

I think I have to use a diode and some resistors and capacitors only. Can they help me in making the oscillator?

 

Nope. You need some solid state parts with gain. I suggest you ask your professor what active components you are allowed to use.

I was refering to the Hysteretic article, which is an oscillator with 3 parts (not counting the speaker), a resistor, a capactor, and the 555 timer chip.

 

Yes you were right.
My teacher still says i cant use it, but all fellow mates are using that only... so i will use that now man.. thanks... do gimme some more information on how itt works as i will also be giving the presentation.. thank you man

 

Hello,

Is the use of BJT transistors allowed?
Then you can use a PNP and a NPN to make a PUT (Programmable Unijunction Transistor).
See these pages how to make an oscillator with them:
http://encyclobeamia.solarbotics.net/articles/put.html
http://digilander.libero.it/nick47/thup.htm

The link come from this EDUCYPEDIA page:
http://www.educypedia.be/electronics/composetriac.htm

Greetings,
Bertus

 

There are still some questions about your assignment. You want to play 3 notes, or have a 3 note organ. In other words, 3 push buttons, each with its own note?

The way you defined it at first was a sequence of notes, which means a sequencer.

If you do go the transistor method, remind him he banned the 555. I have doubts about an instructor who won't define basic parameters, such as devices you can and can not use.

There are actually lots of oscillators out there. Doing a quick search Wikipedia has a old favorite.

http://en.wikipedia.org/wiki/Multivibrator

Put a switch on R2, have R2 as variable, and you have one way. There is also the phase shift oscillator, which only uses one transistor but has a fancier feedback, which you use a switch to select.

http://en.wikipedia.org/wiki/Phase-shift_oscillator

You'll also need to think about how to power a speaker, or whatever you're going to use.

There are definately better out there, this is just what I dug up on the fly.

 

Could not understand a thing man. I have no idea what is this PUT. i tried to read the first link, all went over my head,could not get a thing., the second one is in different language.

 

HEy bill
I have to build an instrument which can play some musical notes.
I chose three notes as i thought it will be easier.
Actually I was told to select a musical tone , say london bridge is falling down, and after finding its notes and frequency, I have to give that range of frequency to the oscillator.
I selected the Windows log on tone, as i thought it is easy, u can tel a different one if u want.
My friends are using 555, and that teacher is liking there stuff, he had not set the basic parameters but when i showed him the circuit design with 4017 chip, and the programming one, he said it cant be used.
But now, I m thinking of using the 555 only as now i have less time.
Still no basic parameters have been given to me, so help me with the easiest and the fastest man, that could play at least one tone. the number of the notes depend on the tone only. and yes, i need the push buttons with their own notes....


Somebody suggested me that i should use the potentiometer instead of the resistors to get the tuning of my own.But I have no idea what does that mean and how will that work.

 

Gee, I suggested the 555 timer in the very first reply to this thread. That was over a week ago.

Have you started reading the datasheet yet?

If not, you better get to studying or you're going to wind up with a big, fat "F" for this project.

 

I get the feeling you want us to draw a schematic. With school assignments YOU need to draw the schematic, that's how it works here. If / when you show the schematic we can help critique it. We will help, but not do the work.

Several 555's can make a sequencer (a 4017 will do it simplier), but there is no easy way to do this. You want easy you choose the wrong profession. It will take 10 555's to do what a 4017 will do. If you need to sequence like you said earlier then your teacher most definately did not forbid a 4017. Stamps, computers, yes, but a 4017 is not complex, it is almost required (that or 6 or more 555s). By declaring something "can't be used" you waste your time and ours. You would be better asking how to use the parts instead.

It sounds (from here) like you're overwhelmed. Start with a single 555, how are you planning on changing the note? How are you planning on sequencing it? Do you know what I'm talking about when I say sequencing?

Sarge, want me to butt out?

 

Bill,
Not at all.

Our OP needs to start with the basics; just learn how to get a 555 timer to work as an astable multivibrator for starters. Once they have that vital piece of knowledge, they can build on it.

If they don't get off their keister and do some work, they're going to bomb their course.

 

I covered the oscillator in post #23, though I doubt he followed up on it.

I suspect some of the terms escape him, which is common enough. I respect anyone who tries to learn english at the same time as electronics, but you need to ask questions if you see an unfamiliar term.

 

I really havent understood that article.
and yes I know u suggested the 555 on the first article , but at that time, i had no idea about it. now i do have some idea.
I surely try to brushup my english.
I know i will hv a F in my assignmnt, bt i jst hope u guys cud help me.
I had shown my teacher a 4017 circuit , i m attaching that file.
I really have no idea about sequencing.
and i dont know wat u mn by ' i want u to draw d schematic'.
Yes, i shouldnt hv taken this field if i want it ez, bt i m stucked, I really am. i can only change nxt yr.
If i fail, i will hv to do ds module again, and ,I know, again i wont understand it.
So i jst wantd tto pass it.
thnx neways fr the try.

 

here is my 4017 crct dt i tried, and my proff. said no to it.

 

Except there is no CD4017. There is a CD4051, and that page is a copy from one of Forrest Mimms books (I read that 30 years ago). CD4017 is a part, a Johnson counter. It counts, and only one of ten outputs are on at a time. You can do much the same thing with ten 555 Monostables connected in a row, just a lot more parts. You need to slow down and read what is written, you are jumping all over the place to conclusions, a lot of them wrong.

A sequencer sequences (look it up), it steps through a sequence. To play a simple tune this is what you need to do.

What did you not understand about the 555 Hysteretic Oscillator? It is about as basic as you can get, and it has pictures and schematics. It is the heart of making a sound. Again, slow down, read, and ask about specifics. Declaring you don't understand it as a whole leaves us unable to work with you. There are several ways to use a 555 as an oscillator, this is the simpliest. Another way to use the 555 is in the experiments in this article, 555 audio oscillator.

You will find if you slow down and read what we are saying that we are giving you clues how to do this. Your instructor expects you to read the technical material and use it to do the project, we are pointing you to material that will show you how to do it. You do the work.

 

thank alot man, gimme sm tym.