[Moved]: Interface Audio Amp to CD4067 IC

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cybertron

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Hi all

Need help Please.

If I can't directly connect an amps output to a CD4067 IC.
It can be any general Audio amp.

Then how do I interface an audio amplifier's output to an CD4067 IC.

A Diagram would be appreciated for connecting the pins.
 

Re: Interface Audio Amp to CD4067 IC

A CD4067 can switch one input signal to one of its 16 outputs or it can have 16 signal inputs and have one of them switched to its output.
For switching audio to the input of an amplifier its load is usually 10k ohms.
Its maximum allowed input/output current is only 10mA and its on-resistance is from 125 ohms to 1050 ohms so it cannot switch audio from the output of an amplifier to a speaker.
 
Re: Interface Audio Amp to CD4067 IC

Then What can I use to interface the audio amps signals output to the 4067. Would an ADC OR DAC WORK SOME WAY to connect to the 4067

The 4067 is replacing a 16 button keypad.It is to mimic the switches on the keypad.
 

Re: Interface Audio Amp to CD4067 IC

You can use the CD4067 to read switch closures or your case emulate switch closures by feeding a grounded Y input to the selected a switch port, as it is bidirectional.

But if the switch is part of a multiplexed matrix ( scanned low and high side), you need a 16P2T cross-point switch which are not popular these days if neither side is grounded. For simple arrays CD4016 switches are used with 4P2S capability.

MUX/DEMUX switches come in a wide variety for both analog and digital applications.
 

Re: Interface Audio Amp to CD4067 IC

Sunnyskyguy

I want to replace these keypads enclosed.And use a chip like the CD4016
WILL the 4016 mimic a 3X4 or 4X4 matrix keypad.

If the CD4016 will not work for me. Can you recommend a Chip that will work for my applications.
But? Can also interface an audio amp outout to the mix.To pick up audio feedback. Read my thread you will understand.

I enclose photo's of the keypads. I want to replace.
 

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Re: Interface Audio Amp to CD4067 IC

THe keypad looks like it not multiplexed with single pins to each port, perhaps NO switches with pullup to logic "1" so the CD4067 can mimic contact closure to ground and also be used to with another chip to carry mono audio sound if AC coupled with bias R to Vcc/2 and then AC coupled to 0V going out with 1V line input type signals. Ground the unused ports for ESD safety. If connection cable is long, you may also need some filtering.

Where is your audio block diagram?
 

Re: Interface Audio Amp to CD4067 IC

cybertron said:
Then What can I use to interface the audio amps signals output to the 4067?
The 4067 is replacing a 16 button keypad.It is to mimic the switches on the keypad.
Click to expand...
I guess the keypad is the dial on a telephone that produces DTMF? There is no audio on the keypad, it is simple logic signals.
We need to know the DTMF encoder IC you are using to see its datasheet.

Can also interface an audio amp output to the mix. To pick up audio feedback? Read my thread you will understand.
Click to expand...
I do not know what you are talking about. Your other thread is about a mic picking up DTMF sounds (and noise and echoes) in a room and there is no "mix".
 

Re: Interface Audio Amp to CD4067 IC


Hi Audioguru

This is for pickup logic signals keypads. Maybe I'm not understanding between the different kinds of keypads. the keypads that I enclosed one has no audio tone feedback but you can add it. the other has an audio beep when you press any of the keys.

The DTMF tone ''thread'' I posted about one mouth ago that you help me on which I appreciated and So did Sunnyskyguy. Is done and completed.
This thread is a brand new. I'am not using a DTMF tone decoder.Unless the audio feedback on on some these matrix keypads.Is that you could pick up DTMF tone.An I'm not using a tone decoder unless it will be need again. The new encoder is 74c922 keypad encoder.some of them have audio feedback when you press a button on the keypad.is that still considered audio tone feedback or DTMF.

Audioguru I bought this one on amazon enclosed
Sorry. I posted the wrong keypad. this is not it. Disregard this schematic.
Its the black keypad I purchased on Amazon.com enclosed.And the red and blue keypad that I posted in last post. The black keypad has no audio feedback But? the red and blue keypad does have that audio feedback when you press any key on the keypad.
 

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Re: Interface Audio Amp to CD4067 IC

When you say "audio feedback" I think you mean that you want to hear a beep when a key is pressed. The keypad decoder IC has an output that goes high when a key is pressed that can turn on a "beep" tone produced by another circuit which is probably built into the red and blue keypad.
The beep has nothing to do with DTMF tones.

Why do you want to replace a 74C922 with a CD4067? The 74C922 has digital outputs to show which key is pressed and also has one output when any key is pressed. The CD4067 only has one output when any key is pressed.
 

Re: Interface Audio Amp to CD4067 IC

I Don't want to replace the 74c922 that is part of the circuit .But it does not have an input to pick up the audio beeps when any key is pressed. I also need a chip that will tell me which key is pressed when I hear the beeps to.Is there a chip i could interface with the 74c922 that will tell me this.using an audio amp to pick the beeps.That's what I mean by audio feedback.
 

Re: Interface Audio Amp to CD4067 IC

The 74C922 has an output (pin 13 Data Available) when any key is pressed, not an input to turn on an external "beep" circuit. The 74C922 has outputs that tell you which key is pressed. These outputs can dial a DTMF IC.

You need an oscillator to make the beep sound that is turned on when the Data Available pin goes high. All beeps will sound the same.
 

Re: Interface Audio Amp to CD4067 IC

Could you tell me How do I connect the 74c922 outputs to the input of pin2 on the 8870 DTMF decoder. there only one input on the 8870 pin two. Do I need another chip between
the 74c922 and the 8870.If so which chip and can you give me the pin out connections.
 

Re: Interface Audio Amp to CD4067 IC

The question makes no sense. 8870 is a DTMF decoder that awaits an audio signal at it's input. Why and how should it be connected to a keyboard encoder?
 

Re: Interface Audio Amp to CD4067 IC

FvM said:
The question makes no sense. 8870 is a DTMF decoder that awaits an audio signal at it's input. Why and how should it be connected to a keyboard encoder?
Click to expand...


In post #12 Audioguru stated the 74c922 outputs can dail a DTMF IC. So the only way to do this is take the 74c922 outputs to the pin 2 input on the 8870. But you can't connect the digital outputs to analog inputs.you will need maybe a DAC.bUT i DON'T KNOW.So what chip can I use to interface the 74c922 outputs to the 8870 analog input.
 

Re: Interface Audio Amp to CD4067 IC

In post #12 Audioguru stated the 74c922 outputs can dail a DTMF IC.
Click to expand...
Yes, he's talking about a DTMF encoder. But 8870 is a decoder IC.
 

Re: Interface Audio Amp to CD4067 IC

FvM said:
Yes, he's talking about a DTMF encoder. But 8870 is a decoder IC.
Click to expand...

He does not mention a DTMF encoder.I'm assuming he would of said encoder. He said DTMF IC.
The 74c922 decodes any key press on a keypad.Not DTMF tones like the 8870. But the 74c922 puts out a 4 bit binary digital code.

I could be misunderstanding what he meant.
 

Re: Interface Audio Amp to CD4067 IC

Can someone help? If you have any ideas or worked with these ICs before. In post #19
 
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