PIC Audio

[peterdeco1]

OK. I have a couple of ideas. Give me a few days to try this one for you. We use the ISD5008 voice recorder IC all the time. I have never tried this but I will check to see if I can modify a program to output the incoming audio directly to the speaker. If so, it's a piece of cake. Releasing the activate button will have the PIC set the ISD chip into playback mode and jump to a memory location that has a prerecorded sound effect (of your choice). If the ISD won't allow this, there is another route to go but at this point I have very limited experience with a new ISD chip the ISD1700 series. With this chip, the incoming audio automatically outputs through the speaker during record indicating you have reached the end of the memory array. In theory, the chip could be addressed purposely to the end of the array. Incoming audio outputs through the speaker. When the button is released, the PIC puts it into playback mode and jumps to a location with your prerecorded sound effect. Again, I just began dabbling with this device and, being a different animal than a '5008, may take LOTS of time figuring out this one. Again, give me a few days to try the '5008 way.

[toofastdave]

Is there a push-to-talk button anywhere that you could hack into to trigger a PIC into making the sound for you? The 'push' would arm the PIC to make the sound, and after the 'push' has been held for X seconds, it would actually be armed, then the 'release' would trigger the PIC to make white noise for X ms.

Naaw, it's all hands free. The unit has to be in the helmet and there is no way to constantly keep pushing a button...especially when you are talking, holding stuff (blasters) and moving around. The armor is pretty complicated and you can't have any wires showing anywhere. You have to interact with the people around you so it would be very distracting to have to keep pushing the button everytime.

OK. I have a couple of ideas. Give me a few days to try this one for you. We use the ISD5008 voice recorder IC all the time. I have never tried this but I will check to see if I can modify a program to output the incoming audio directly to the speaker. If so, it's a piece of cake. Releasing the activate button will have the PIC set the ISD chip into playback mode and jump to a memory location that has a prerecorded sound effect (of your choice). If the ISD won't allow this, there is another route to go but at this point I have very limited experience with a new ISD chip the ISD1700 series. With this chip, the incoming audio automatically outputs through the speaker during record indicating you have reached the end of the memory array. In theory, the chip could be addressed purposely to the end of the array. Incoming audio outputs through the speaker. When the button is released, the PIC puts it into playback mode and jumps to a location with your prerecorded sound effect. Again, I just began dabbling with this device and, being a different animal than a '5008, may take LOTS of time figuring out this one. Again, give me a few days to try the '5008 way.

Does this chip have a logic pin that indicates when it is receiving audio? If so, you could eliminate the switch and have the PIC monitor the login state instead of having a switch. The unit I am looking at doesn't have any switches except to program it... I'm not really asking anyone to build this for me but I don't have ANY experience with audio so a little help would be great! Maybe suggest a chip that could do something like this or a combination of chips. I know you mentioned the ISD series. I could DL some of the data sheets to look them over.

Thanks!
Dave

[Pic_User]

Hi Dave,

Do you have a substitute amplifier board that will amplify your voice? That part may be a little tough, to get a PIC to amplify audio.

If you have an amplifier board or could build / buy one, the PIC may be able to do the rest.
Instead of a mechanical push-button switch, the A/D input or the comparator input could be used to “trigger” on a preset level. Some times called “VOX” (voiced operated transmission), this is used for hands free transmitter control.

You could tap into the audio and allow an adjustable threshold (voice) level to tell the PIC to be ready to playback your sounds. When the level drops below the threshold for a programmed period of time that would tell the PIC to play the sound now.
In other words; the PIC senses you are talking and then, that you have stopped talking. So it plays the sound, into the audio amplifier.

You have to figure out how to get the sound you want out of the PIC.

Interesting project
-Adam-

[toofastdave]

Hi Dave,

Do you have a substitute amplifier board that will amplify your voice? That part may be a little tough, to get a PIC to amplify audio.

If you have an amplifier board or could build / buy one, the PIC may be able to do the rest.
Instead of a mechanical push-button switch, the A/D input or the comparator input could be used to “trigger” on a preset level. Some times called “VOX” (voiced operated transmission), this is used for hands free transmitter control.

You could tap into the audio and allow an adjustable threshold (voice) level to tell the PIC to be ready to playback your sounds. When the level drops below the threshold for a programmed period of time that would tell the PIC to play the sound now.
In other words; the PIC senses you are talking and then, that you have stopped talking. So it plays the sound, into the audio amplifier.

You have to figure out how to get the sound you want out of the PIC.

Interesting project
-Adam-

Adam,
Yes I was planning on using an external amp..not sure which one yet but using the A/D comparator sounds like a great idea! The noise I want the PIC to simulate is just static or the short squelch sound that you hear when you unkey a transmitter... Forgot to mention that the board I am trying to emulate is driving 8 ohm speakers... I think it's pushing like 8 watts at 12vdc.. It's actually pretty loud in the video that I watched.

I figured since I have PBP and Proton Plus that I should be able to beat the 105 pound sterling ($210.00us) price for the board if I build it myself. Like everyone else though, I just lack the time.. I'd buy the dang board if he had them available just to save myself the trouble.

-Dave

[Pic_User]

Hey Dave,

Do you have a link to the board you are looking at?

You may want to make a band pass filter to get the restricted radio voice type sound.
The PIC could add the rushing radio sound (squelch tail) at the end of your “transmission”.

If you have the schematic of the amplifier that would be handy.
You could add a rectifier stage to rectify the voice audio. Use this audio voltage to charge a capacitor. Monitor the capacitor voltage with the comparator or A/D of a PIC. Let the PIC decide you have been talking and now you have stopped (for a certain length of time).
Have the PIC produce a “burst” of white noise.

We all know about lack of time (seems to be universal), do what fits.
If you do find time to make your own, you could add stuff. Like color LEDs. Green most of the time, red to show you are talking, blue to show “end of transmission”......
Maybe the red LEDs could be a line of LEDs that travels back and fourth while you are speaking?

-Adam-

[toofastdave]

Hey Dave,

Do you have a link to the board you are looking at?

You may want to make a band pass filter to get the restricted radio voice type sound.
The PIC could add the rushing radio sound (squelch tail) at the end of your “transmission”.

If you have the schematic of the amplifier that would be handy.
You could add a rectifier stage to rectify the voice audio. Use this audio voltage to charge a capacitor. Monitor the capacitor voltage with the comparator or A/D of a PIC. Let the PIC decide you have been talking and now you have stopped (for a certain length of time).
Have the PIC produce a “burst” of white noise.

We all know about lack of time (seems to be universal), do what fits.
If you do find time to make your own, you could add stuff. Like color LEDs. Green most of the time, red to show you are talking, blue to show “end of transmission”......
Maybe the red LEDs could be a line of LEDs that travels back and fourth while you are speaking?

-Adam-

Adam,
Sorry for the late response, I've been on the go all weekend. I like your ideas and can probably incorporate them into the design initially to help with the design. The link to the board I am trying to emulate is

http://www.romfx.com/

Check it out and go to the Audio / Video page and you can listen to what the board actually does. I know the PIC will play tones.. but do you actually think you can produce an un-squelch sound?

-Dave

[Pic_User]

Hi Dave,
There are two things that you may want to try.
Find a way to band-pass or “restrict” the audio going through your amplifier.
This will make your voice sound like it is coming over the radio (like a telephone voice sound).

I have never made white noise with a PIC.

The PICBASIC Pro manual says it is possible with the sound command.
See PBP manual: 5.78. SOUND
SOUND Generates tone and/or white noise on the specified Pin.

You may have to make a filter similar to the one in the DTMFOUT section.
See PBP manual: 5.17. DTMFOUT
Maybe leaving the signal as a white noise square wave would enhance the “radio” sound. This will be a low level volume. It will have to be injected into the amplifier at a low level stage. Hope someone that has used the white noise jumps in here.

If you are set-up to breadboard the PIC SOUND command, you should try it to see (or hear) for yourself. It should sound like the burst of broken squelch a radio makes when turning back to receive.

This sounds like a do-able project but it may take you a little more time that you might expect. The fun of doing it would be the reason, not the money saved.

-Adam-