I am looking for a device that meets the following criteria. a) Reasonably small. This probably wouldn't be rack mounted; it'd be wall 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 http://www.edtp.com 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