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Re: My yearly post about environmental monitoring devices

  • From: Owen DeLong
  • Date: Thu Dec 02 11:55:50 2004

I don't know if they're here yet, but, PICs with builitin Ethernet are
definitely on the way. I'm not that much of a hardware geek, but, some
of the hardware geeks I know have bee talking about these for a while
in terms that make me think they're expecting samples any day.


--On Thursday, December 2, 2004 11:42 AM +0000 [email protected] wrote:

I am looking for a device that meets the following criteria.
a) Reasonably small. This probably wouldn't be rack mounted; it'd be
mounted, desk mounted, celing 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.
d) Provides Temperature and Humidity.
e) Has 4 or so input contact sensors (connections to AC units, etc.)
f) Has 4 or so output contact sensors.
Sorry Alex, but I think you are barking up
the wrong tree. A cheap simple temperature
and humidity sensor would be built around
a PIC chip and would use a serial bus
to communicate status. Since this is 2004
that would be an I2C serial bus, but in
reality an RS-232 daisy chain would suit
this application just fine.

When you add Ethernet as a requirement
then you are asking for an I/O interface
that is more complex and more expensive
than the basic temp/hum recorder on the
PIC. However, it definitely is possible
to do this and many people have done so.

I suggest that you go to a company like and tell them what you
want and how many you would buy in the
next year as well as an estimate of how
many they could REALISTICALLY sell to
other companies in 2005. When you look at
the prices on his website, remember they
are single unit hobbyist prices. I think
that a PIC board built around his packet
whacker Ethernet would do what you want
and could easily be powered with PoE
and be installed in a box with flexible
mounting options. If you can't get what
you want from this company, then start
looking for people who do PIC development.

You might even be able to get a college
sophomore to design and manufacture these
for you for some spare pocket money. The
PIC code including TCP/IP stack, is readily
available through googling. The only area
where you might have to compromise is
SNMP since I think most people who do
this are trying to make PIC web servers.
But it's simple to run a custom SNMP proxy
on a server if you need to hook this
into your management system.

Please report back on what you find.
I think a lot of people would be interested
in this type of unit.

--Michael Dillon

If it wasn't crypto-signed, it probably didn't come from me.

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