Electronic Music Box Project

[bluechilledkola]

Hi,

My kids and I are thinking of making an electronic music box / piano combined with a crank & wheel with interchangeable pegs to play the notes.

Our problem is that we were only able to find a 13-note electronic organ DIY kit, and the sound is rather irritating and earsplitting as compared to a piano's soothing sounds. We were also able to get a small bell kit, but it only plays 1 pitch, we need a multiple-pitch chromatic scale . We are not experts in electronics but we do know how to build the circuit by reading the instructions lol.

The image and schematics of the kits that we have are below:

13-Note Organ:
Image:
Schematic: http://www.apelectronics.co.za/Stores/toptronic/ArticleImages/FK243E-1.PDF

Small Bell:
Image:
Schematic: http://www.futurekit.com/2009/MANUAL/future/eng/PDF_FK2/fk251e-1.pdf

Being a noob, would really appreciate it if someone could help us with our queries :)

1. Is there a simple way to change the sound of the electronic organ kit into a piano, bell, or music box?
2. If the 1st is not possible, can we add a potentiometer to the small bell kit to adjust the pitch? If yes, how do we do this? (a schematic will be great)
3. If both options above are not possible, is there an existing DIY electronic kit out there that can play the 13 notes but in a piano, bell, or music box sound?

Thank you very much gurus!
- Blue -

[audioguru]

The electronic organ uses a squarewave generator IC. A squarewave sounds like a buzzer.
A completely different circuit can make a sinewave that sounds like a flute or make a triangle wave that sounds something like a violin.

The piezo beeper in the bell circuit creates a tone at the resonant frequency of the piezo and its housing and this frequency cannot be changed.

You could make a variable frequency sinewave or triangle wave oscillator and have its output level ramped slowly down with part of the bell circuit.

[Hero999]

The trouble is, to get an authentic sounding bell, you need to adjust the decay time along with the frequency so a low pitched bell rings for longer than a high pitched bell.

[Guest CN_santon]

In my opinion,I think you should learn more about the timer IC NE555. You said that the sound is irritating,as you see in the design introduce material,the 13 resistor is used to change the frequency of the sound.It also depend on the value of the R14,R13 and R14.I am not a music professor , I don't know much about how the frequency affect the tone.This design just give you a method to design a music box(In fact, the circuit is so simple and I doubt that if it  can play music on it.),but you must try to adjust the design to satisfy yourself.I think that while you can make 13 different tone,you should cheer for the success of this design,do not except too much,like make it replace a piano or other things.
The speaker's sound is only supplied by the NE555(2nd pin).You can try to make the output current lower to solve the soothing sounds problem(The sound is too noise,right?I am a Electronic information college student from China,my english is so so,I am not sure if i understand you ideas).
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1. Is there a simple way to change the sound of the electronic organ kit into a piano, bell, or music box?(I think you have got my idea.And here is a free software about how to change output  voltage wave of the NE555:http://www.schematica.com/555_Timer_design/555_Timer_Free.htm)
2. If the 1st is not possible, can we add a potentiometer to the small bell kit to adjust the pitch? If yes, how do we do this? (a schematic will be great)(It can not help,the frequency is the key factor)
3. If both options above are not possible, is there an existing DIY electronic kit out there that can play the 13 notes but in a piano, bell, or music box sound? (Of course it have,but it must be complex,at least,not as simple as this design.The normal solution is use the DAC(digital to analog ) products,and need the micro controller.

[audioguru]

In my opinion,I think you should learn more about the timer IC NE555. You said that the sound is irritating

You should also learn about the 555 IC, its output is a square-wave. You should also learn that square-waves have an irritating sound like a buzzer or an amplifier with its volume turned up way too high. The loudness and frequency have nothing to do with the irritating sound.

A flute has a smooth sine waveform. A violin has a triangular waveform.
All musical instruments have formed rise (attack) and fall (decay) times, and are not abruptly turned on and abruptly turned off like a 555 oscillator.

[Guest CN_santon]

Er.....I may not understand what the "irritating sound" means....I just play attention on its duty ratio and do not consider about the edge leave change problem. :-[