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isd sound recording confusion

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breadboardguy

New Member
There is something that i dont get, if you go on the isd website:

Nuvoton - parsehqweb

you see that the lowest rec time is 4 sec, so how can i play a sound that is 2 seconds :confused:

I need so to make an laser tag system. Maybe i can rec a 2 sec sound then 2 seconds of nothing? Will i be able of getting another sound out of the chip while that "nothing time"? Can someone tell me please?
 

Mr RB

Well-Known Member
If you are going to be using a PIC or other micro, I have a nice software tool here;
(PicSound home page) Official Home Page of the Roman Black
that lets you turn wave files into 1bit sound and then you can pay back the 1bit sound just by setting an output pin on the PIC. So you dont need an external sound chip.

2 seconds will fit into the program rom on most of the larger PICs or you can use external eeprom etc to store the sound.
 
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neophyl

New Member
I dont see anywhere that states a 4 sec min record time from that page. Are you getting confused with the sample rate ?

The old lasertag circuits I used to build used the older ISD25xx and it was relatively easy to get a pic to play back the sounds. I was routinely using 20+ samples for various gun functions.
 

breadboardguy

New Member
they say :

ISD18A04 4-8 sec /4~8 /DIE 0 - 50ºC P Y ISD-COB18A04
ISD18B00 ISD18B12 6- 12 sec /4~8 /DIE Commercial P Y ISD-COB18B24
ISD18B24 12- 24 sec/4~8 /DIE Commercial P Y ISD-COB18B24
 

neophyl

New Member
Thats Max duration of record time ie 4-8 seconds max. You will have to download the actual datasheet for each of the devices you are considering to see if that devices capabilities meet what you actually want it to do.

From your description you need a device like the outdated ISD2500, one that has a simple 'push button' addressing mode, multiple message playback etc. Id check if those DIE chip on board devices that you list have all these capabilities first.

The ISD devices are constructed of cells (varying in size depending on device). Each recorded sound uses X number of cells so for each sound there is a little wastage but not alot.
 

neophyl

New Member
Im not familiar with the newer devices but the older ones had multiple modes of operation.
They could either be controlled with an address bus and extra control lines (10+ pins used on the microcontroller), for this you also need to know the start address of each sound recorded to the chip.
The other mode was a simple 'push button' mode, this operated a bit like a cd player, in that you could skip 'tracks' (sound samples) with one line, and upon reaching the one you want just trigger the play line. This combined with a reset to zero of the sound pointer meant that you could control playback with 3 microcontroller pins (a 4th pin was used to disable the audio amp during skip to stop noise during that process).

This method is what is used by the the original Battlefield Sports lasertag gear and is also the method used by later systems such as milestag. I should know as I designed the original BFS kit :)

I suggest once again that you thouroughly read the appropriate datasheets and get an understanding of how the devices are controlled and addressed otherwise you wont be able to write software to interface to them. Its also a damn good idea for selecting the device to go with in the first place.
 
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