Custom USB Server Alert System

F

FoxFlame

Limp Gawd
Joined
Sep 3, 2005
Messages
143
Yeah I didn't know where to put this one...Audio and electrical engineering are my weak subjects. My basic question is audio related, but nothing else about it is so it's going in 'General Hardware':

I need an inexpensive device capable of easily emitting a very noticeable 'noise' across a household. Louder is better.

[Backstory]
I'm a data center engineer. I need to be aware when certain 'critical' events occur regarding my occupation. Nagios sends to my phone. That's fine. The problem is that I don't always have my phone on me, and I can't always hear it. (E.g. Sunday afternoon when I'm playing video games with my headphones on. Nope, don't keep my phone tucked into my robe on vibrate...)

So I need an alarm. I need it to be both audible across the house, and visual anywhere I might have headphones on. But I have all that sorted out.

I'll use an old laptop running CentOS (and probably eventually Raspberry Pi) that simply obtains emails forwarded to it through my ISP from our data center, or via the internal network if my phone gets a call instead. (Need redundant paths if either fails) From there it can easily enable the only USB devices connected. (via a shell script) The usb cable splits the appropriate number of times (as yet undecided) and switches to Cat6, where it can then run through the house to whichever plugs I want. Then back to USB where it can easily start powering alerting devices. (E.g. 'Woot-off' lights, or countless other devices)

The problem I'm running into is finding an acceptable aural alerting device that can easily be powered off 5VDC. This seems like it should be very simple. I know there are speakers capable of USB power (5VDC) but every piezo siren/horn/alarm/buzzer I've found requires 12VDC or 9VDC. I'd rip the noise maker out of those little water alarms but they too require 9VDC.

Yes, I could use a powered USB hub prior to splitting down in the server room, but I was hoping to avoid doing that. If I must, I will. I could also just take USB speakers and attempt to instead play audio files across them, but that's far more complicated, requires way more space, and frankly, I just need to know something is wrong, not precisely what is wrong. I'll figure that out when I get to my phone.​
[/backstory]

I'm not sure what happens if I were to apply only 5VDC to a 'noisemaker' that typically requires more. I suspect it would either be quieter or not function at all.

If I'm missing a blatantly obvious, efficient, simple, inexpensive and robust solution here, please let me know. (No, I will not be dual tasking another system in the house like my receiver or whatnot. This system is critical; it must have a single device dedicated to it. Receivers and personal computers can get turned off when used by other people. Each link in a chain is a potential point of failure.)

Any assistance with this is greatly appreciated.
Thank you,
--Fox
 
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Moved to Networking and Security subforum. Fairly sure someone else has had a similar requirement.
 
If you're feeling creative, you might want to look at an Arduino (www.arduino.cc). You can easily power Piezo sirens and bright LEDs with one. There are also plenty of wireless and wired networking examples.

Also, to answer your "noisemaker" question: If you use an internally driven Piezo and drive it at 5V instead of its rated voltage, it will simply be quieter. I use Piezo's rated for 12v - 24v in 9v systems all the time. If 5v is too far below the operating voltage to produce a loud enough sound, you can use a simple boost regulator from Pololu to bump that 5v up to 20v.

I have used these in the past (although not from that distributor): http://www.amazon.com/Alarm-Siren-1...UTF8&qid=1355202532&sr=8-1&keywords=12v+siren

The volume is above the pain threshold, and much louder than a typical US police siren.
 
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That's what I was looking for! Thanks guys; I'll let you know how it turns out. (I'll basically assemble it in steps with the least amount of pieces first to see if it's at acceptable levels and add relays/boosts if required)


And maybe one day in the future use a relay to power something like this:
http://www.amazon.com/Yellow-Rotating-Mechanical-Signal-Buzzer/dp/B008OULB7Y
:D
 
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Well that's no good. Attempting to modify /sys/bus/usb/devices power via the control file and autosuspend doesn't work against 'dumb' devices. Looks like the motherboard constantly feeds +5VDC across pin 1 regardless and cannot be controlled by the software.

I'll need a smart device of some kind (A managed hub or something) to pull this off...

Update: http://www.gniibe.org/development/ac-power-control-by-USB-hub/index

I don't understand why this isn't more prevalent. Why is nothing I want to do *ever* easy?
I'm starting to think I should have done this via RS232.
 
Last edited:
FoxFlame said:
Well that's no good. Attempting to modify /sys/bus/usb/devices power via the control file and autosuspend doesn't work against 'dumb' devices. Looks like the motherboard constantly feeds +5VDC across pin 1 regardless and cannot be controlled by the software.

I'll need a smart device of some kind (A managed hub or something) to pull this off...

Update: http://www.gniibe.org/development/ac-power-control-by-USB-hub/index

Or this: http://www.instructables.com/id/A-USB-Power-Controled-Plug-Strip-With-Isolation/

I don't understand why this isn't more prevalent. Why is nothing I want to do *ever* easy?
Click to expand...

Sounds like a project for an Arduino.....
 
All the Arduino items I've seen appear needlessly overpriced for this project, from what I've seen at least. The simple act of enabling or disabling power via USB shouldn't cost that much. Maybe I'm looking in the wrong place, or haven't researched Arduino enough, but the cheapest item I've seen to do this task is $25. It certainly won't break the bank, but a $10 USB hub and a program compiled in C will do the same thing, yeah? I'll research it more in a bit though. (When I'm sober!)
 
wizdum said:
If you're feeling creative, you might want to look at an Arduino (www.arduino.cc). You can easily power Piezo sirens and bright LEDs with one. There are also plenty of wireless and wired networking examples.

Also, to answer your "noisemaker" question: If you use an internally driven Piezo and drive it at 5V instead of its rated voltage, it will simply be quieter. I use Piezo's rated for 12v - 24v in 9v systems all the time. If 5v is too far below the operating voltage to produce a loud enough sound, you can use a simple boost regulator from Pololu to bump that 5v up to 20v.

I have used these in the past (although not from that distributor): http://www.amazon.com/Alarm-Siren-1...UTF8&qid=1355202532&sr=8-1&keywords=12v+siren

The volume is above the pain threshold, and much louder than a typical US police siren.
Click to expand...

I was going to post this as well. Would be really easy to do with arduino, the hardest part is making whatever program actually send the signal via serial to it. I found that Python makes it the easiest. It's a pain trying to get serial communication to work with C++, just too many little flags to worry about.

So basically you'd code the arduino device to have a basic serial interface that takes command, one command to ring the alarm, one to stop the ringing. Could even go a step further and have minor, major and critical so you could have a set of 3 tones and 3 lights.

I'm guessing the alerts come in as emails, so what you could do is setup Procmail which would then run the email through a custom app that would parse it out then send the proper signal to the arduino.

You'd just need an Arduino uno for this project, they're rather cheap, like 30 bucks.
http://www.canakit.com/arduino-uno.html

I remember when I was a kid making a simple electrical circuit to activate a Piezo siren from my room to stop my dad from snoring. Got it at Radio Shack (called "The Source" now) maybe they still carry those.

Could also just write an app that plays a wav file but then you have to depend on the speakers being turned on and loud.
 
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Red Squirrel said:
I was going to post this as well. Would be really easy to do with arduino, the hardest part is making whatever program actually send the signal via serial to it. I found that Python makes it the easiest. It's a pain trying to get serial communication to work with C++, just too many little flags to worry about.
Click to expand...

Completely forgot about this. Theres a program called "Gobetwino" that can run on a PC and act as a go-between for the PC <-> Arduino connection, if you don't feel like writing your own program for the PC. http://mikmo.dk/gobetwino.html
 
That's kinda neat, too bad it's only for Windows though. Though that just gave me an idea, rather than using python to write specific code to access the arduino, I should write a generic script that simply listens to a TCP port locally and relays to the serial port and vice versa. Would be fairly easy to do too.

I use arduino for environmental monitoring. Only have a few monitors on it so far but I plan to add more. Right now I have AC power fail, DC voltage, and mouse traps. Yes, mouse traps. I know, I'm a nerd. :p Have temperature too but that's using another system.
 
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