I'm working on a project that I'd like to have ethernet connectivity for. I have very little "in the weeds" experience with networking, so bear with me if this seems ultra-basic.
The Arduino in question will be monitoring simple stuff - temperatures, etc. I want visibility into this "stuff" from anywhere. Twitter seems the best solution, since I can check it from any computer without having to log into email, and/or FWD to email or SMS by "following" the twitter account.
My goal is to get the Arduino to post to a twitter account once an hour, or some other set frequency. Plus, post to a different twitter account when alarm conditions exist. This way, I can check the first "normal" account through a web browser when I'm curious, and have the second account set up to email and SMS me when an alarm triggers.
Seems like any of the common interfaces can do that. My criteria are simple:
I want an Ethernet interface that takes up as few resources on the Arduino as possible - memory is already filling up, and I'm running out of pins. I'd like to preserve all 6 PWM pins, if possible.
I'd also like to not have to code the thing from the ground up, so an Ethernet interface with good examples for tweeting would be best.
Cheap is always good!
It seems like my choices are as follows:
An "official" shield with a Wiznet W5100 chip
A shield (like ladyada's) with an Xport interface
A shield like the cheaper of the two from seeedstudio, with an ENC28J60 interface
I've read through threads where people have used all three of these, but I'm having a hard time evaluating them based on my criteria above. Any suggestions?
I did something similar. Check out Tom Igoe's book Making Things Talk and the cat email project. In this case the Arduino is hooked up to a computer running Processing that listens for changes from the Arduino and then calls a PHP page that sends out the actual Tweet.
I have never tried connecting by Ethernet, but have used the WiShield by Asynclabs with good success. It connects wirelessly to your home network. You might also look at Pachube and triggers. You can upload data to Pachube and set it to trigger stuff. One example might be to hook up temperature sensor to Pachube. If it reaches a theshold then Pachube could call a PHP page to send out a tweet.
Thanks for the suggestion. I really don't want this to be tethered to a PC or any other intermediate hardware. Maybe I got into the details too much - basically I'm looking for a dirt-simple comparison of different Ethernet interfaces, based on:
of pins consumed
Typical memory consumed for tweeting
Cost
People get into some of those concepts on posts from time to time, but I'm having trouble putting the pieces together.
The wireless stuff sounds cool, but it's more expensive and I'm guessing it's more resource-intensive, but maybe I'm wrong there.
Have you looked at the products from AsyncLabs? The ethernet module does use up two of the PWM lines, but you could pair a WiShield 2.0 with a Seeeduino Mega and still have a ton of I/O lines left over. I think the YellowJacket is really cool too, provided it has enough I/O for your application. For only $55 you get an arduino and WiFi.
Interesting, but I don't want the cost/complexity of wifi.
FWIW this is for a custom Arduino clone, so I can't just switch to a Mega.
Really just interested if someone can give a comparison for the typical ethernet interfaces: ENC28J60, Wiznet W5100, XPORT, etc. based on the criteria of resources used, coding required, and cost.