Maybe your robot goes on by itself because you failed to use shielded audio cable to connect to the mics, and your unshieded wires pickup interference like mains hum and local radio stations. Unshielded wire makes a great antenna.
no i said it has the problem without the mics mounted on the preamp(the problem is from the preamplifier, yes it is really a lousy preamplifier design)
The datasheet for your pic shows that its inputs respond to TTL levels: 0.8V or less is low and 2.4V or more is high.
The output DC voltage of the mic preamp is floating at rest because the PNP transistor is off. Therefore the input to the pic is also floating somewhere between a high and a low. Who knows what the pic thinks it is? You disconnected the preamp, same problem. The LED won't pull the input low, a resistor to ground will pull an input low.
Connect a 1k or 10k resistor from the pic's input pin to ground to make certain the input is low at rest. The PNP transistor can easily pull it high when there is sound.
i used from two 1k resistors between the pic inputs and the ground but with no change at the pic outputs,
Try it and it might work. :lol:
But it is still a lousy mic preamp design. :cry:
Didn't we post some good mic preamps in your other thread? :?: