Anyone need a project? [SNMP temp sensor]

Dec 03, 2004 1 Replies

I hang out with a bunch of network admins [they let me post to their list if I don't talk BGP...] and one (and likely most...) are seeking a environmental sensor:



a) Reasonably small. This probably wouldn't be rack mounted; it'd be wall mounted, desk mounted, ceiling mounted, etc.



b) Powered by PoE.



c) Is SNMPable over Ethernet. NOT RS232 or serial, or anything archaic like that. Not MODBUS. It's 2004, people. [Hey, I add, what about Fallon PhoneNet....]



d) Provides Temperature and Humidity measurement.



e) Has 4 or so input contact sensors (connections to AC units, etc.)



f) Has 4 or so output contact sensors.



I added:



g) cheap, so as to encourage quantity deployment.



to the requirement set.


Now, absolutely accuracy is not a big issue; they just want to know when the AC has quit, or the humidity is WAY too low, etc.



So what do the collective geniuses of s.e.d think is the best solution?



A host is a host from coast to coast.................wb8foz@nrk.com & no one will talk to a host that's close........[v].(301) 56-LINUX Unless the host (that isn't close).........................pob 1433 is busy, hung or dead....................................20915-1433

Except for a) small, b) PoE, and g) cheap, there are already such products on the market for monitoring the power, door contacts, temp, humidity, etc. in data centers. Start with the UPS manufacturers.

There are several small/cheap Ethernet project sites out there, but none are doing PoE yet that I've seen, so you'd need to roll that in. Here's a popular one that'd need to be trimmed back to reduce cost:

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Linear has been doing PoE for years now, heavily in Cisco's products:

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And an article on PoE:
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On the super cheap side, start with something as a derivative of

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- add PoE, a handful of input and output drivers for the contacts, and a one-wire sensor for temp and humidity. Or maybe something like the project boards here:
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More expensive, more compact, and closer to turnkey, products like the XPort and DigiME are pretty slick but don't offer PoE last time I looked.

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comp.arch.embedded would be another place to ask around.

Have fun! Richard

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