Please help me in debugging the circuit!

[bashok0011]

Hi

I started a project in electronics and I done everything in it but still a problem crept in n the circuit is not working. I need help in this regard!

The project is KnockLock. Its aim is to detect knocks on the door and determine if they are in correct pattern or not and to Lock or open the door based on the knock pattern detected. I got the design onto PCB. Microcontroller is flashed with program and ready. Somewhere there is a problem I am unable to diagnose. Please help! I am attaching a schematic of the circuit I made. The circuit should wait for a knock, detect asap its done n work accordingly. But the circuit on PCB is detecting a invalid knock as soon as the electet microphone is powered up and is never returning back from that state. The knock pattern should be waited for after 8 sec from detection of a invalid knock. But No, It shows invalid knock, Just in its way! Thanks if u can bail me out!



Ashok

 

[KMoffett1]

Not a lot of info!
Looks like PD2 and PD5 should have pull-up resistors. Floating inputs can cause all kinds of program problems.  That would be my first guess.

Ken

 

[bashok0011]

Yes there are input pins and have pull up resistors,,,there are no floating inputs which is why reset bar pin is connected to Vcc..!  Please have a look at the transistor configuration, i think there is a mistake there in it., somewhere there t3 biased and nothing is happening..Please advice me onto how to change this?

 

[audioguru2]

T1 is so poorly biased that it might be saturated, cutoff or linear.

The collector of T2 is connected to ground. It should be connected to +5V.
The emitter of T2 should have a resistor to ground.
T2 is also poorly biased.