My project idea .......!

[alpharhinonxt]

If the chemicals were to fizz up you could have your students press the Big Red Button which sends a text message to your phone alerting you about the situation.

[fuzzball27]

I thought you're NEVER supposed to push the red button?

what kinds of chemicals are you working with ("Gas" seems a little too vague)

[alpharhinonxt]

Yeah don't we love to yell that
"Don't push the red button!!!"
Sorry if this is shouting Xander but you have to admit it is funny

[helumpago]

Sorry if this is shouting Xander but you have to admit it is funny

Hmm, I just noticed something when you said this. Not even a month ago the above comment would've been directed at the now-inactive Brian Davis. I take it Xander's the new main ban-hammer? Welcome to you're new position of power, oh benevolent leader!

[muntoo]

Welcome to you're new position of power, oh benevolent leader!

Grammar mistakes will cost you's.

Also, the reason that the students are supposed to press the big red button, is so that they blow up the entire city. That way, there's NO chance of contamination.

[stryker001]

If you have a [non-NXT] gas sensor on hand, you should just be able to wire it up and use it as a 'touch sensor' in the programming. Just read the analog value coming from the "touch sensor" and determine the gas level based on that. Just an idea, though.

- Stryker

[mattallen37]

Just read the RAW value of the port. You will also need a 5v supply for the filament, and it needs more current than pin 4 can supply. I would build the circuit like the light sensor, so you can turn off the filament from within the code.

[fuzzball27]

I think we're drifting off topic (besides matt and stryker)
You say you want an alarm that is sent to the students; would that be a displayed message, an audible message, etc.?
Again I ask, what kind of chemicals are you trying to detect? (I see that gas wasn't the original wording)

[mightor]

Welcome to your new position of power, oh benevolent leader!

Who said anything about benevolent? As for moderators, there are 4 of us now. Steve H, Brian D, John H and myself.

I wouldn't rely on the NXT as your main monitoring system for a gas detection system. I am pretty sure it's not rated for that sort of thing

- Xander

[timpattinson]

I was searching Google Cache for useful info from nxtasy to post on Mindboards and I found this. It's about CO2 gas detection, but it might be relevant.
http://webcache.googleusercontent.com/s ... clnk&gl=au