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Music Effects with 4017 and 555

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afs87

New Member
Hello to all!

I have just had an idea for a music effects generator. I hope this is not too muddily.

A push switch could trigger a 4017 to move to count 0. This would trigger a 555 monostable which would in turn trigger a 555 astable. The astable would be set to a specific frequency to play a particular note on a 64 ohm speaker (eg. A=440hz). The monostable would time how long the note plays for. When the monostable comes to the end of the timing period it would then trigger the 4017 clock input and the 4017 would move to the next count. This would then repeat the same as above but with a different note of course.

This setup could be used to play a tune. However there are a few problems:

1) Is it possible to have the 555 triggerable by logic 1?
2) How could the 4017 move onto the next count when the monostable reaches the end of the timing period?

If anybody could solve these problems I would be very grateful.

Thank you.
 

mechie

New Member
Fascinating !

Hmm,
Not the most obvious way of playing a tune but why not?

Question...
If the 4017 is triggering the monostab which steps the 4017 (full circle),
why not just have a slow 555 astab clocking the 4017 ? the result would be the same but easier to set up ?

The rest actually sounds fairly straight forward !

Any takers to draw a circuit ?
 

afs87

New Member
Re: Problem

mechie said:
Hmm,
Not the most obvious way of playing a tune but why not?

Question...
If the 4017 is triggering the monostab which steps the 4017 (full circle),
why not just have a slow 555 astab clocking the 4017 ? the result would be the same but easier to set up ?

The rest actually sounds fairly straight forward !

Any takers to draw a circuit ?
This was my original idea but by using that method the gap between notes would vary. Eg. if the 555 had a delay of 1 second and a note had to play for 1/4 of a second then there would be a long gap and if another note lasts 1/2 of a second there would be a short gap. Of cource there would be a need for a gap between notes but not a gap which changes between long and short. Thank you for the idea anyway.
 

mod_critical

New Member
The method suggested actually would work fine. Just clock the 4017 ( prolly multiple of them chained) at a rate of say, one eigth note at 120 bpm. Then for a quarter note connect two consecutive 4017 pins to the same tone generator, with diodes. Then for an eigth rest leave a pin diconnected, and two consecutive for a quarter rest.This method will work fine, but you will need to have several 4017's chined to play simple melodies (four measures would require four 4017's [32 distinct eigth notes, thus 32 pins])
 

mod_critical

New Member
afs87 said:
1) Is it possible to have the 555 triggerable by logic 1?
2) How could the 4017 move onto the next count when the monostable reaches the end of the timing period?
Sorry about that. To answer your question, a 555 could be triggered by logic 1 by driving its Vcc (pin 8 ) through an NPN transistor from the logic source. a 4017 could be incremented by falling edge by connecting the monostab to a PNP transistor that would have its emitter connected to the 4017's clock. when the monostable goes low (falling edge) the transistor will allow flow to the clock of the 4017. The 4017 will increment (rising edge) and when the monostab is reactivated and its clock goes high, the emitter of the PNP will go low and the 4017 will not react. (this once the monostab goes low again the 4017 will increment once more)
 
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