Path: utzoo!attcan!utgpu!jarvis.csri.toronto.edu!mailrus!purdue!decwrl!shelby!unix!hplabs!hp-sdd!ncr-sd!serene!pnet12!gbell
From: gbell@pnet12.cts.com (Greg Bell)
Newsgroups: sci.electronics
Subject: Re: Sine wave generator
Message-ID: <794@serene.UUCP>
Date: 21 Jul 89 04:36:07 GMT
Sender: root@serene.UUCP
Organization: People-Net [pnet12], Del Mar, CA
Lines: 37

cook@stout.ucar.edu (Forrest Cook) writes:
>In article <790@serene.UUCP> gbell@pnet12.cts.com (Greg Bell) writes:
>>I'm wondering two things:  What's the best/easiest way of making an electronic
>>doorbell?  I'd prefer the attention-getting sound of a "ding-dong", that's why
>>I'm going to all this trouble.
>
>Greg, here is a possible solution that could be programmed to make many sounds:
>
>[oscillator]->[4040 counter]->[EPROM]->[DAC]->[low pass]->[amp]->[speaker]
>      ^-----[flip flop]<---stop---|
>start----------^
>
>You could store both the ding and the dong waveform as a sequence in the
>EPROM, which could drive the DAC and output a digitized waveform.
>Generate the desired wave form with a program and burn it into the EPROM.

I've thought of that, but thought there'd be a better/cheaper way of doing
it... a more "conventional" way perhaps.

It just so happens I have an A-D, D-A, some RAM, a monitor EPROM, and an 8031
sitting in breadboard form on my desk in front of me.  I was basically trying
to record sound and play it back.

My goal is to have a telephone ringer that screams instead of rings 8-). 
Could do any number of other sounds too.  Biggest problem is getting the audio
digitized, and burned into an EPROM.  

My experimentation with A-D and D-A is producing questionable results.  I
really need to ad an anti-aliasing filter to the input, some low-pass on the
output, and a sample and hold circuit.  Problem is, I'm outta breadboard
space!  I need to wire-wrap the 8031 brain portion so I can free up the
breadboarding sockets for more fooling around.

    Greg Bell_________________________________________________________
      Hardware hacker          |
      Electronics hobbyist     | UUCP:  uunet!serene!pnet12!gbell
      EE major at UC San Diego |