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Subject: Re: Can anyone help me to build addtional features to the two switches
to control a toy?
Date: Sat, 30 Nov 2002 15:44:23 GMT
NNTP-Posting-Date: Sun, 01 Dec 2002 02:44:23 EST
Organization: BigPond Internet Services (http://www.bigpond.net.au)
> I need to design a Module for a Y-cable so that two switches must be
> pressed to activate one toy (to teach cooperative play with 2
> students) with jacks on all ends so that a variety of switches and
> adapted toys can be used.
> With help, in general this is what I have to do in order to activate
> a toy by pressing two swiches.
> for each one toy:
> battery + and -, call them Batt+ and batt-
> toy+ and toy-
> switch1 contacts, sw1a and sw1b
> switch2 contacts, sw2a and sw2b.
> Now, connect batt- to toy-.
> Connect batt+ to sw1a.
> Connect sw1b to sw2a
> connect sw2b to toy+
> Thats it! Only when both switches are on will the toy get power.
> In addition, more features are required to add to the design, JUST
> RIGHT AFTER THE FIRST SWITCH IS PRESSED:
> I need to build an indicator such as light or LED to signal that the
> first switch is already pressed.
> And the same time when indicator led turns on, a recorded voice plays
> (such as music or command voice, it said "the first switch is already
> pressed, press the second switch now, counting down 3, 2, 1). In
> this case if the person press the second switch during the recorded
> voice plays, the recorded voice has to be terminated right away.
> Do I have to use an addtional power source to power an indicator and
> the recorded command voice? How do I connect it? What kind of chips
> should I use? Can anyone help me with information so I can build this
> particular design?
> Thanks alot.
As an alternative to Al B's EPROM option, which requires an EPROM
programmer (a device rapidly going out of common use), you could simply
use a small micro with an A/D and a serial flash. At 8000 samples a
second a 256kbit flash chip gives you 4 seconds of speech, a 1Mbit
serial flash gives you 16 seconds. 2 input wires for the switches, a
microphone through an LM358 or LM386 for input. Output through a PWM
signla to an LM386. OR alternatively - get one of the early ISD
sssspeech recorder chips, on a pre-built board, these are easily found.
Wire the trigger for the board to the 'first switch pressed' detector,
wire the reset to the 'second switch pressed' detector
This project would be easiest to implement on a small micro. It could be
done in logic if you can't find any friendly engineers or hobbyists
nearby with a spare PIC.