Simple (I think) problem with very basic drum machine

[Pancra85]

Thank you very much for taking the time to read this and help me!

I designed this circuit which I think is a pulse generator, made with a 555 IC, counter and an inverter to generate a ryhtm for the drum machine:
Out of the picture (down) is a hi-hat circuit.

First of all this part is working fine, it generates a desired pulse and is having no problems by itself, also the hi-hat works fine in rhythm.

I also made two PCBs for this circuit: **broken link removed** and connected each one (bass and snare) to the designed pins on the right of the first image. That also works fine by itself.

As I also want the drum and snare to be triggered by a button when the snare and bass ryhtm is disabled (by disconnecting the switch on the right of the first image, next to the snare and bass rhythm output pins) so I also connected a button to +9v and the other pin of the button to each trigger and THATS WHERE THE PROBLEM IS.

When I press the bass button it first triggers a bass drum sound, but when I realease it it makes a snare drum sound, also it seems that the snare button doesn't triggers the snare at all.
I tried putting a very small resistor (10 ohms or 220 ohms) from bass trigger to GND but it makes the same thing.

Help pleaseeeee??? Thanks!!!

 

[BradtheRad]

When I press the bass button it first triggers a bass drum sound, but when I realease it it makes a snare drum sound

Looking at your attachment, it appears that the 'bass-activation' wire is connected to the input of the inverter (node labelled '3'), whose output is labelled 'snare'.
You probably need to install a diode in the bass wire, so that none of its switch action gets back to node 3.

it seems that the snare button doesn't triggers the snare at all.

There's the question as to what part of the waveform triggers a snare sound. Is it the positive-going edge, or the downward-going edge?
Does the incoming snare signal produce the necessary waveform?

You may find out what is the necessary waveform by examining what comes from the 'bass' activation wire.

 

[Pancra85]

THank yo uvery much for answering, I tried adding a diode between the bass pin and the trigger of the bass and another diode between the snare pin and the trigger of the snare sound (tried before and after the other pin of the button but it works in a weird manner)
Well... I might only make it to sound in "automatic mode" without the buttons triggers.
Thanks again!!!

 

[Pancra85]

I really want to give this another go, because having two trigger buttons will add a lot more functionality to the device.
I corrected the schematics as BradtheRad told me it could work, so it's clear for everybody.

There's the question as to what part of the waveform triggers a snare sound. Is it the positive-going edge, or the downward-going edge?
Does the incoming snare signal produce the necessary waveform?

You may find out what is the necessary waveform by examining what comes from the 'bass' activation wire.

The snare trigger works if the bass it's not connected, I should point out that the bass sound and snare sound are the same circuit (erik's Mini Space Rockers, the black schematic on a few posts above)

Any ideas?

Thanks!

 

[BradtheRad]

To use technical terminology, you need to figure out whether pulling a wire low activates the snare, or pulling the wire high.

Then you'll get a better idea how it is influenced by the bass activation wire.

This is a typical challenge when working with logic signals and switching, namely what polarity makes which event happen. Also the effort to keep track whether a wire being 'high' (or low) can interfere with something else happening or not happening.

The problem is solvable. It may be a matter of where to put (or not put) an inverter, or which direction to orient a diode. Etc.