Beowulf Cluster Monitor

Lobo05

I am interested in using a Basic Stamp Microcontroller to monitor the enivronment within a 25 node Beowulf Supercomputer.·

What is the best stamp and board to use along with three of the temperature and humidity sensors.

Also, I would like to use the ethernet board to write software to update a webpage with this information, and email me on the off chance that the environment changes.

And another idea I had is to use the modem to call me, and because of caller id I would recognize the problem and respond.· Can I use both the ethernet controller and the modem together?

Suggestions and or ideas are welcome.

Thank you

Paul Baker

Any stamp should work since temp/humidity doesn't change very fast, though Id get a BS2 at minimum (mostly for the extra IO and program space).

Sensirion makes temp + humidity chips: http://www.parallax.com/html_pages/resources/catapps/cat_humidity.asp

Pink internet module: http://www.parallax.com/detail.asp?product_id=30013

Most BS users use Ceramtek modems.

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Lobo05

Thank you Paul,

I looked at all of these pages prior to posting a thread (I read the drama with digital DJ) and didn't want to ask an idiotic question, but I need to order parts before the holidays and didn't see if there were any design constraints required by each of these models, or if anyone had had problems with the Ceramtek modems and the Pink internet module working on the same controller (i.e. ip packet routing problems or things of this nature).

The cluster (which is a work in progress) is the more pressing issue (being used for quantum computing applications).

I will go with your advice and order these parts in the next couple of days.

Happy Holidays

Paul Baker

Dont worry, Im actually helping DigitalDJ in-depth off the forums (weve nailed down the direction we'll be going and after the holidays we'll proceed further in the direction we chose, the chip we are using as the basis of his project is so versatile and interesting I'll be building a duplicate board myself and will be using as a more general purpose module, after we are done, he will be posting everything in the completed projects forum (it was my only condition for my help)).

I dont think there would be any problem having the same stamp interfaced to the modem and internet module, do I understand that current aquired data will be posted on the website, and the modem will be used only if the data passes preset safety threshold(s)? (at which point you'd check the website to get the actual data).

Its good this isn't urget, since the PINK is backordered, though you could still have the alarm functionality. Id still order it though to make sure you get one when the next shippment of the module arrives.

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Post Edited (Paul Baker) : 12/14/2005 9:49:11 PM GMT

Lobo05

Paul,

That's correct, the system is stored in the basement of a chemistry building next to a high powered laser, so there is an immediate concern that the environment of the room is susceptible to serious changes of temperature and humidity...such as if we need to lower the temperature in the room so that the laser acts properly.· Also, since we live in the high desert, the humidity is very low and there is always a risk of static electricity.·

The plan is to use the modem to give a ring only if there is a serious problem with the environment in the room.· It would also be really neat to have a smoke detector interface with it...to cover all ground (so if you have heard of one that works).· We would like to be able to respond to the system asap in case something goes wrong.· The purpose of the website is to update the information on a real-time basis, we hope to eventually be able to notify users (or post an alert) when a series of calculations converge...since this usually takes a couple of days.

APC sells things like this, but they are set up to monitor systems that sit in a computer room where in general the environment is well controlled.· We have things like cryogens, chemicals, lasers...etc all in the same room so this system will be more unique.

Best of Luck with your project with DigitalDJ.· I will be interested in viewing the outcome.


·

Philip Gamblin

If the smoke alarm has an audion output, it should be not impossible to detect and respond to it. You could use a "Clapper" interface.

Paul Baker

Like Philip said, you could detect the sound, or using a scope, you could find what kind of signal is sent to the buzzer then tap it (with possibly some interface circuitry) to directly detect the signal sent to the buzzer.

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Lobo05

That's a great idea, looking at info for a smoke detector last night I found that it should be trivial to detect the signal...I am assuming that it uses something like a comparator to detect when the current in the ionization chamber changes current levels...then probably has a high on the output (probably not as simple as that....). However, I am sure that it should be relatively simple. I was thinking that since parallax had a module for most everything else that they might somehow have a smoke detector (or someone had developed one).

Anyway, it should be cheaper to do it with a $7 smoke detector anyway. Thanks for all your help.

SPENCE

I am not shouting. I have been able to read and type all caps much easier for over 55 years.

Reference the smoke alarm. `smoke alarms for security systems are already wired for a output to a external system.

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73
spence
k4kep

Tracy Allen

Most ionization smoke detectors make use of a single integrated smoke detector chip, the MC14467. It contains both the electrometer amplifier and the alarm generation circuit that monitors both the smoke and the battery level and drives a piezo disk.

I is quite possible to pick off the analog signal from the output of the electrometer amplifier and feed it into an analog to digital converter. The MC14467 is a 16 pin DIP, and usually pin 15 is not soldered to the circuit board,which helps identify the orientation of the chip even from the bottom of the circuit board. The top of the chip is usually hidden underneath the ionization capsule. Pin 15 is not connected to the circuit board, because it is the input to the electrometer amplifier and it is bent up and connects directly to the high impedance sense electrode hanging free in air. The electrometer voltage can be tapped at low impedance at pin 14 on the chip. (Pins 14 and 16 are "guard pins", which isolate it from stray currents and drive up the input impedance.)

I know a lot about Stamp interface to smoke detectors, as I developed this project:
ehs.sph.berkeley.edu/hem/page.asp?id=27
Since the ionization detector contains radioactive Americium, the radiation safety office has to approve and track every units we place in service. We also make use of photoelectric smoke detectors, but the interface is much more complicated.

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Tracy Allen
www.emesystems.com

Orion

Most 110v powered house hold detectors sold around me have a three wire hookup. 2 are for the 110v power and the third for interconnection between others in the house. One goes off they all do. It outputs 110v during an alarm and would be trivial to interface to a stamp.


search homedepot.com for

BRK Electronics
Direct Wire Ionization Smoke Alarm



Post Edited (Orion) : 12/16/2005 2:46:49 AM GMT

Paul Baker

Ah so thats what the third wire is for, I wondered when yanking it from the ceiling the other night when a grease fire started in the oven. The sad thing is the third wire goes nowhere, you'd think the apartment complex would have that signal goto a call box or something. Guess it's time to get renter's insurance.

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Bruce Bates

Paul et al-

Just a bit of clarification. This thread has already mixed system and non-system smoke detectors, so let me start there. Safety, is never off-topic, IMHO.

System smoke detectors are generally not 110 volt (or whatever line voltage is), they are ALWAYS connected back to a (generally) supervised central panel. and nearly always there is also what's called an "end of line" (EOL) resistor at the end of that single alarm circuit. The purpose of the EOL resistor is to guarantee the integrity of that particular alarm circuit.

If the central panel "sees" anything on that line other than the EOL resistor, and the specific voltage (if appropriate) that it's sending through that circuit, the panel will set a TROUBLE indication for that circuit. The cental panel will annunciate as it has been set to do.

If the central panel "sees" either a voltage (if appropriate), or continuity (other than the EOL reistance, if appropriate) coming back on the return wire, then that circuit goes into ALARM status. Again, the cental panel will annunciate as it has been set to do.

Other types of sensors (heat detectors, etc) on such a central panel operate in a similar manner. Often, these are 24 volt systems. Usually one only sees these types of central alarm systems in commercial buildings or "places of assembly" (a fire and building code term).

Non-system detectors are used in other locations. "Other" includes residences, so long as there are not more then [noparse][[/noparse]some statuatory number] of dwellings or residences, within one building framework. The determination of "separateness" may depend on whether there are extant firewalls in the building. Depending on the specific and particular circumstances, this "statuatory number" may be locally, county, state or federally derived.

Non-system smoke detectors generally come in two types: ionization, and photoelectric. Which ones are permissable is usually based on the fire codes which are recognized in that particular state, or in the overriding decisions which may locally supercede the state fire codes, so long as they are more strict or stringent.

Both photoelectric and ionization smoke detectors can usually be "interconnected". Interconnection provides for a "one-alarms, all sound off" operation. One should NOT interconnect smoke detectors of different types (ionization and photoelectric) unless the manufacturer provides for such an arrangement. One should NOT interconnect smoke detectors of different brands, either. There is no mandated standard for how this interconnection is to take place (voltage used, polarity used, presence or absence of signal, etc) therefore the necessity of the prohibitions above.

Local, county, or state fire codes will determine whether interconnection is required by law. If it is NOT, there is no earthly reason why it still can't be employed optionally. During initial installation, before the walls and ceilings are up, this is easy. After the fact, it may be a bit more difficult.

I hope that was helpful, and not too boring.

Regards,

Bruce Bates

Tom Walker

On a slightly more "low-tech" approach, one could just sense for the "sound" of the annunciator that should be hooked up to the detector. I would recommend listening for more than one occurence of the annunciation, to filter out the random loud noise...such as the one that a human might make when the laser does something "interesting".

Caution: Do not look into laser with remaining eye.

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Truly Understand the Fundamentals and the Path will be so much easier...

Lobo05

Thank you all....for all the great information as to how to approach this project. The posts have been extremely helpful and we look forward to posting the finished project on the Forums.·

Thanks Again