Hi


I have one speaker in my system and two sound sources. First sound source is the uC which generate a short wave on its pin making shound and other is a ISD chip which plays a stored voice message. both use speaker. my problem is how to mix them so that both use the same speaker. Here are two systems.

- there are two pins on ISD chip +S and -S both connect to speaker.

- 12V to speaker, speaker to TIP125, TIP to ground. Base of tip driven by uC.


So how i make these two system share the same speaker. Do i need to use relays which can be controlled to connect one system to speaker... but that will make system design expensive. Already using two relays.



i know this is not a 8052 question but i have this place where i get instant answers to my questions. please do let me know about any good group on net where i can post this sort of questions.


THanks a lot
Shahzad Aslam