Slider2732
Newbie level 4
555 on off switch
Hi there, first post here
I've hit a problem that would seem rudimentary and easily solved :|
I'm changing the circuit of an eprom based sound samples player, so that a small 1 octave keyboard can be used.
Design is similar to: **broken link removed** in the 'Hardware' section.
Each key must start the 555 oscillator and also, when pressed, enable a connected resistor to change the oscillation rate of the 555...forming a rudimentary keyboard, with different value resistors (a resistor ladder could also be used).
My main problem is that of using a switch (keyboard key) to both switch on the sample playback and also set the rate. For some reason, the 555 stops or doesn't trigger.
As things currently sit, I can press the original on/off switch, which is the Pin 3 output connection between the 555 and the 4040's and then change the pitch using a resistor arrangement. The resistors all have a common tie to each other at one end and each switch is connected to the other end. This gives the rate changing desired. But, the original on/off switch has to be held down and thus playing the sample anyway, for the rate to change on pressing one of the rate change switches.
No amount of diode useage, or even an opto-isolator has solved things, so that a switch will both start the sample playback and change the rate at which it does so.
....so I thought i'd ask here
Hi there, first post here
I've hit a problem that would seem rudimentary and easily solved :|
I'm changing the circuit of an eprom based sound samples player, so that a small 1 octave keyboard can be used.
Design is similar to: **broken link removed** in the 'Hardware' section.
Each key must start the 555 oscillator and also, when pressed, enable a connected resistor to change the oscillation rate of the 555...forming a rudimentary keyboard, with different value resistors (a resistor ladder could also be used).
My main problem is that of using a switch (keyboard key) to both switch on the sample playback and also set the rate. For some reason, the 555 stops or doesn't trigger.
As things currently sit, I can press the original on/off switch, which is the Pin 3 output connection between the 555 and the 4040's and then change the pitch using a resistor arrangement. The resistors all have a common tie to each other at one end and each switch is connected to the other end. This gives the rate changing desired. But, the original on/off switch has to be held down and thus playing the sample anyway, for the rate to change on pressing one of the rate change switches.
No amount of diode useage, or even an opto-isolator has solved things, so that a switch will both start the sample playback and change the rate at which it does so.
....so I thought i'd ask here