[K12OSN] OT: what do you use to schedule you schools bells

Jim Kronebusch jim at winonacotter.org
Tue Feb 19 15:53:48 UTC 2008

On Mon, 18 Feb 2008 09:52:57 -0600, Timothy C Litwiller wrote
> I need to find something "free" or very low cost to run the bells at our 
> 28 student private school. I think I have found a relay switch that I 
> can control with usb and wire into the bell circuit along with the the 
> push button.
> But I need some software that the teachers can use to schedule.   I can 
> setup the default - but some times things get changed around for a few 
> days and I don't want to have to be there for every change.

Well, our school already had an intercom system run throughout that we used to make
announcements and to play chimes with our old bell system.  However our old system only
allowed us to have 4 preset schedules to rotate, we needed far more.  I started looking
at different systems that could play 15 or so schedules, and the cost was ridiculous,
especially to make a chime.  So I built a minimal install Linux box with a sound card. 
I then recorded some voice messages in wav format (each message simply states the name
of the schedule for the day).  Then I found some chime files in wav format.  I created a
bunch of cron files in /var/spool/cron, all named with root.nameofschedule.  The cron
jobs simply call out times of the day to play the chime wav files and the voice
messages.  I then created a script for every schedule that simply runs a command to swap
in the correct cron job for the schedule of the day.  Then I set up webmin with a bell
user that only has access to the "Schedule Commands" module.  Now anyone can log into
this and schedule the commands for the next month of bells.

If anyone is interested in the scripts let me know and I'll post them to the list. 
These can easily play music or anything at scheduled intervals.

When finished I connected the sound card of the Linux box to the amp that runs the PA
system.  Problem solved for free.


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