I like to challenge myself. Today I decided to figure out how to convert This high school project aka School lock-down system into a useful technology.
If I understand correctly, one of the possibilities of pursuing this project involved detecting sound and if the sound is so loud it will cut on lights. However, the technology I have in mind is a completely different concept therefore starting a new thread was in order.
As many of you probably already know from previous college experience, to much sound (and/or cars parked in the center of the street) will attract undesired attention "police". You have also probably noticed when people start drinking they tend to become louder and louder which typically results in someone turning up the music so people can hear it.
I know this because I lived in a frat house for a few years and I was the one in charge of keeping everyone out of trouble. I ended up rigging the houses sound system so that the speaker wires went under the house, then up through my room and cross two light switches located in my room, then went back under the house and to the speakers. If things got to loud I could flip the switches and no one could do anything about it, and few knew what the cause of the sound outage was caused by. Most thought it was a power overload in our sound system. I would then flip them back on after 5 minutes or so which would result in people restraining from the urge of turning the music up to loud.
But if I had the system that this group is interested in designing I would have installed the sound detector outside (probably in the shed where it would always stay dry) and have it communicate wireless to another arduino which would act as the arduino that controls the light system in their case. Instead of turning on lights, why not have it turn on the wire that leads to a PnP transistor? That little bit of current from the arduino would flip the transistor to open (break the connection) to the sound wires so it would cut the sound off. You could then install a 5 minute timer program that way the system would automatically turn itself back on, and besides the few brothers living in the house, everyone would assume the system overloads itself if the music is turned to high.
What I am now curious about is not the way the arduino detects sound, but rather if this PnP transistor would be able to take the current from pin 2 of an arduino Uno when high, and open the switch to a speaker wire, or a lamp even to turn it off? For practicability sake well say the arduino is controlled by a webserver phone app rather than a volume identifier.
Is it possible? Would this PnP transistor work?