Public School bell system
Cogburn
Posts: 62
Hey guys,
I teach at a small rural high school in Central Arkansas.· Our current bell system for changing classes and for fire drills, tornado drills,etc. is an antiquated electromechanical system whereby small metal tabs placed in the movement of the clock actuate a switch that rings the bells.· Of course there are ways to manually override the automatic bell system but really no good way to select different ringing schedules as in the case of pep rally days or days when we have an assembly or speaker.· This alternate bell schedule is a big pain as our secretary has to watch the clock and manually ring the bell at different times.
I want to build a system that will allow a dedicated PC (old pentium 2)to be used to select which bell schedule to use and to provide a way (bs2?) to actuate a solid state relay at certain times to do the task.· Of course the GUI should be user friendly (something a secretary could use) to select the schedule and still provide a manual override for tornado drills etc.·
I guess what I am asking is some advice on the best way to proceed.· Is the ds1302 and oscillator capable of giving me what I want with appropriate code or perhaps the pocket watch B with the BS2 or pocket watch with visual basic code?· This project will tax my programming abilities I am sure and I may have bitten off more than I can chew but I would really appreciate any advice anyone has on the best way to proceed.· I plan to use a solid state optically isolated relay to connect to the 120 V electrical wire that will·actually ring the bell.·
It is not a big problem if the "clock" loses or gains a few seconds a day as it can be reset periodically.
What about the internal clock in the PC with some VB code to actuate a relay through the serial port?·
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Showing up to school doesn't·mean you are a student any more than crawling up in an oven means that·you are a biscuit.
I teach at a small rural high school in Central Arkansas.· Our current bell system for changing classes and for fire drills, tornado drills,etc. is an antiquated electromechanical system whereby small metal tabs placed in the movement of the clock actuate a switch that rings the bells.· Of course there are ways to manually override the automatic bell system but really no good way to select different ringing schedules as in the case of pep rally days or days when we have an assembly or speaker.· This alternate bell schedule is a big pain as our secretary has to watch the clock and manually ring the bell at different times.
I want to build a system that will allow a dedicated PC (old pentium 2)to be used to select which bell schedule to use and to provide a way (bs2?) to actuate a solid state relay at certain times to do the task.· Of course the GUI should be user friendly (something a secretary could use) to select the schedule and still provide a manual override for tornado drills etc.·
I guess what I am asking is some advice on the best way to proceed.· Is the ds1302 and oscillator capable of giving me what I want with appropriate code or perhaps the pocket watch B with the BS2 or pocket watch with visual basic code?· This project will tax my programming abilities I am sure and I may have bitten off more than I can chew but I would really appreciate any advice anyone has on the best way to proceed.· I plan to use a solid state optically isolated relay to connect to the 120 V electrical wire that will·actually ring the bell.·
It is not a big problem if the "clock" loses or gains a few seconds a day as it can be reset periodically.
What about the internal clock in the PC with some VB code to actuate a relay through the serial port?·
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Showing up to school doesn't·mean you are a student any more than crawling up in an oven means that·you are a biscuit.
Comments
If you go the stand-alone route, this article will certainly help you move data between a VB app and the BASIC Stamp:
http://www.parallax.com/dl/docs/cols/nv/vol3/col/nv89.pdf
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Jon Williams
Applications Engineer, Parallax
·· I also have something that might help, and is both along the lines of what you want to do, as well as what Jon was pointing out.· I built a digital thermostat some time ago.· It checks the DS1302, displays the date and time, and checks the temp and displays that too.· But for the ability to have it set the temperature automatically at different times of the day it also checks a list of pre-programmed times, as well as the date to determine what the temperature should be at that time.
·· You could do the same thing by re-vamping the code to simply activate the bell at the correct time.· And, when you needed to alter the schedule, you could do that without really interefering too much.· I used a battery-backup on mine so that when I re-programmed it, or when the power went out it didn't lose the time.· I also added the ability to store certain settings in the DS1302's RAM which would be checked on startup.· If you think that would help, and you want a solution without the PC being dedicated, I could post the code.
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Chris Savage
Parallax Tech Support
csavage@parallax.com
Please post the code for your temperature monitoring program with time checking.· I would be interested in seeing how you made it work.· I think I could use it for my project in a modified way.
Thanks,
Cogburn
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Showing up to school doesn't·mean you are a student any more than crawling up in an oven means that·you are a biscuit.
·· Here it is, I hope it helps.· The section that checks the date and time could be easily modified for your use, and they could be updated as needed by simply updating the source code.· If this needs to be maintained by a secretary, then it could be adapted to use a data table that could be optionally downloaded from a computer.· Or the edits could be done in the source code as I was doing, although I don't know if that's feasible for your situation.·
·· Also note that this program expects the time on the DS1302 to be set already.· I actually used another program to set the time and then loaded this one.· Eventually I was going to add a feature to detect when the clock wasn't set and do it within this code, but I never got around to it before I moved to CA where I don't need heat!· Anyway, good luck.· If you have questions on the code, post them here and I will try to help you out.
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Chris Savage
Parallax Tech Support
csavage@parallax.com
We run a Weather Radar and there are some 'instant alarm' occurances that we want to know of with a doorbell system.
So, we run in some TTL signal lines from our system and have an old DOS program that will detect certain instances in a given time for these few faults (that was a mouth full).
Then what happens is it sets DTR high (or somehting like that...can't quite remember) and this line goes to a 'blackbox' with some 555's set up for the ding and the dong of the system. (there's a few relays in there to switch the 120V to the bell system too).
We also happen to have this system tied in to a modem that will call out to a pager system and give us a simple code based on the particular alarm situation.
I haven't skimmed the other posts....but you mentioned using this bell system for fire alarms...just note that you can not tamper with the fire system unless you are licensed to do so!
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·
Steve
http://ca.geocities.com/steve.brady@rogers.com/index.html
"Inside each and every one of us is our one, true authentic swing. Something we was born with. Something that's ours and ours alone. Something that can't be learned... something that's got to be remembered."
·· He's talking about the bell for classes.· Like to switch classes, and for fire drills.· Not the fire alarm.· In any event I would be for not relying on a PC due to the need to keep a battery backup system on it, etc.· Using the Stamp would be a lot cheaper, and probably more fun too!
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Chris Savage
Parallax Tech Support
csavage@parallax.com
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Showing up to school doesn't·mean you are a student any more than crawling up in an oven means that·you are a biscuit.
I am prototyping a system based on·the·OUT &h378,0 and the OUT &h378, 255 commands to control the output of the parallel port of an old 486 running Qbasic.· I have the timing features working well using TIME$ and nested IF, THEN, ELSE statements for the 16 times a day that the bell must ring.· I am able to turn on an LED from the printer port of the computer for any number of seconds desired when the computer time equals the desired bell ringing times.· I will put a nice menu for the GUI that will direct the secretary to choose which bell schedule she wishes to run that day.· I will test the ttl output tomorrow to see if I am able to activate the SSR to turn on a 120V light bulb.·
As I go through this, I am more and more wanting to·explore a different·approach·using·a BS2IC and maybe a pocket watch B.·I am thinking·about a wireless·setup with some·debugin statements that would allow the secretary to·initiate the proper bell schedule from her desktop.··Without a menu to choose from, I·worry about the secretary's ability to initiate the proper schedule without help.·
Anyway, thanks for all the help.· As I explore the other method, I may be back if I run into trouble.
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Showing up to school doesn't·mean you are a student any more than crawling up in an oven means that·you are a biscuit.