Need help on a ground keying circuit

[dss56]

So I have a sound module that is 4mb storage not much about 3 minutes of time.
Module has 8 channels for playback if set up for mp3 player. And thats how i have it set up.

Problem is if you ground any of one of the 8 channels the channel will activate when ground is applied.

2 ways to set up
1 will be when grnd is on any channel channel will play and stop when thru playing.
2 will play but will stop when ground is removed from any channel.

Main problem is if ground is constant to either modes sound will repeat until ground is removed.

this will be activated by pin 3 on most radios to key the module but if you keep the mic keyed sound repeats and i dont want that.


Is there a small circuit i can build to just pulse any one channel to go low and then high so I can keep the mic keyed after the sound is played using the pin 3 on say a cobra 29ltd.

Talking a bout 1 second ground pulse is all thats needed so after sound is through with mic keyed I can start to talk with out the sound repeating.

thanks for any help

here is a youtube link of the module

DY-SV17F MP3 Player Voice Module 4MB Flash Voice Playback 8 Channel IO Trigger Serial Port Control USB Download FLash​

 

[NZ8N]

I used to build Digital Voice Recorders out of ISD1000's from Radio Shack (and other such, Memo Mates, etc...) in the mid to late '90's. My design was that when a play line was triggered, automatically keyed the radio and held it keyed until the sample was finished, by sampling the voltage from one of the sound out lines, to power a transistor, to key the radio.

Does that module run "stand alone" ? Without external CPU control? Does it record too?

 

[dss56]

NZ8N
Dont think i can do that here because any of the 8 channels repeat as long as ground is present.
I need something when the mic is keyed a channel will see ground and then go high while the mic is keyed so when sound is finished person can talk. Un key the mic then keyup and start the cycle all over without the channel be in the repeat mode. Dont know if im explaining what is happening. LOL

 

[nomadradio]

Needs a monostable multivibrator. Commonly called a "one-shot". More than one way to do this, but it's bedtime. Film at 11.

73

 

[brandon7861]

Can you use a capacitor and pull up resistor?

The blue trace represents the voltage on Pin 3 when the PTT is pressed and released. The yellow trace is the test point Pulse. By sampling the PTT line with a capacitor and having a pull up resistor on the other side of it, when pin 3 goes low, both sides of the cap go low, and then the pull up resistor begins charging the cap again so it don't stay low. The zener holds the right side of the cap from spiking the 8v regulator when PTT is released.

Edit: The zener is chosen to be just above the PTT high voltage. Depending on the pull down current required to activate the noise toy, the noise toy itself may be able to serve as a pull up. The cap and resistor value used are not ideal, just used them to illustrate the idea. This can be dialed in better with some measurements. 1uF and 100k would be a far better starting place because the values I used in the top circuit would lead to surge currents an 8.2v zener's datasheet isn't going to comment on.