Cheap Ethernet indoor temperature sensor

cheap? Today, can't be done for less than $75 cost; now double this at retail. No consumer market for such.

I use Maxim/Dalls one-wire sensors; $3 each; connected by phone wire, daisy-chained. Connects to $30 interface on PC serial or USB port.

If you want to ethernet-enable those devices (and know Java) you can use the Dallas TINI board which has a 1-wire bus and ethernet ability.

But as Steve mentioned setting up a 1-wire network and connecting to an existing PC is really the easy approach. Here is a open source project which uses this same system for HVAC zoning control.

-jr

stevech wrote:

Thanks! Java is good. I wrote an interface to my Napco alarm system in Java.

I'll check it out.

John

I agree that it can't be done for less than $50 today although I don't agree with your cost figure. Mouser has the Lantronix xPort for $49 and it's about $35 in OEM quantities from Lantronix. Add a PIC and thermistor and the cost is just over $50 even for one off.

This will shortly change. Microchip has announced a single chip Ethernet interface (ENC28J60) and Digikey lists it for under $10 in single quantities. Once it's available it will be economical to Ethernet enable almost any µController based project (assuming the µController has enough horsepower). If you use the QFN28 package it won't even require much board space.

Search

for the ENC28J60 datasheet and for the retail price.

"stevech" wrote: