Circuit to play sound after speech (reverse VOX)

Electronics Project Please the document attachment for a full illustrated description of the project. Concept for circuit as follows: 1. [url removed, login to view] mono amp runs from 9v DC PP3. 2. Passive 300Ω mic is connected to amp which is powered through amp circuit. 3. 2 x 20mm 8Ω speakers are connected to amp in series. 4. Digital Voice Recorder (DVR) voltage needs to be stepped down to approximately [url removed, login to view] with no extraneous drain through the voltage regulator. 5. When sound (from mic) ceases playing, the DVR circuit module plays a sound that has been pre-recorded ??" in this case a burst of static. The idea is create the end of PTT static burst sound on a shortwave set, E.g. I say “Hello, my name is Jim?? kssshhhttt (static sound plays that is digitised in DVR). The sampled sound plays for about 300ms and the delay between end of speech and sound sample should be 0 to 100ms (ideally controlled by a POT). 6. Sound output from the DVR needs to fed back into the amp. I tired connecting this directly to the output jack of the amp (no amplification). The sound was not quite loud enough. So, the sound from the DVR needs to amplified somehow. Without amplification, the output from the DVR is about [url removed, login to view] AC at peak volume. 7. It all has to fit in a box which is no larger than 69mm x 67mm x 19mm. I use a modified switchable 4 x AAA battery box to house the circuits. A relay will probably be too big although a miniature reed switch may work, better still, a 555 or NPN / PNP transistor. So, essentially, this is a VOX in reverse. The DVR is triggered after sound ends rather than when sound begins. My electronics skills are very basic ??" I’m a web designer, not an electronics guy. I purchase both circuits "off the shelf".

## Deliverables

1. Solution for the description of the project as above and in the attached document. 2. Will be in the form of a built, tested and functioning circuit or group of components. I am not skilled enough to start building circuits from schematics. 3. The project may be controlled by a PIC but this must be very low cost. 4. All circuit boards (including the 2 x existing circuits) and additional components must fit in an existing case that is 69mm x 67mm x 19mm. The completed project will be controlled via an external 9 volt PP3 battery. 5. All components must be readily available. 6. If an additional circuit is required, design, tooling costs and manufacture must be economic. 7. All designs, manufacture and solutions must be copyright free. 8. A clear schedule must be provided so both parties understand the time scales involved. 9. The completed design solution will need to go through a full test cycle before going "live".

## Platform

Electronics. Possibly PIC ??" Basic or other language.

Usługi audio Cisco Elektronika Oprogramowanie wbudowane Inżynieria Mac OS Odd Jobs

Numer ID Projektu: #2814074

O projekcie