The other thing you can do is go to a serial LCD adapter.  I ran out of pins on my very first project with a display because it takes so darn many pins to run the display.  I went to a serial adapter and haven't had a problem since.  Something like the LCD117 from Modern Device will do the job with only one pin (you don't need input from an LCD), power and ground.

http://shop.moderndevice.com/products/lcd117-kit

I love these little things and there's a bunch of them out there to choose from.  I do not recommend the 5V ones from SparkFun, they take up too much real estate with the oversized board, they work good though.  A serial adapter for the LCD and NewSoftSerial so you don't have to worry about serial ports and away you go.

I've had to replace the control unit twice on my dishwasher.  Both times because the darn thing got wet and rotted.  It was under warranty, but would have cost me a lot.  Needless to say, if it happens again I'll be copying your project  ]

I'll never be able to match the incredible job you did on the front panel (the nearest hacker space is 1.5 hours away), but I certainly could put in an arduino with XBee remoted to my overall house controller.

One thing though, my experience with hot glue has been less than satisfactory here in the Arizona heat.  It's great if the temps stay within reason, but ......  You may need to look at nylon standoffs, nylon screws and some of that epoxy putty to hold things on.  The epoxy putty for plumbing that you can get at the hardware store is really great stuff for hot and wet situations.  Sure, you will be sealing it as well as you can, but this stuff is cheap and easy.

Darn nice job, show it off to everyone that come in your house.

Shoot, I don't have a laser. 

Really, that is one of the best looking front panels I've seen and I want to know how you did it.  Don't you want a rinse and hold button though?

How the heck did you do that?  That is really nice.

If one of them breaks, the others route around the broken one.  It's a way of the network taking care of itself.  Really nice in a situation where you need to keep things working, just add a couple of strategic devices and keep a spare on hand that you can bring online when you need it.  This way a temperature sensor also works as a router to carry the data from some more remote sensor that in turn acts as a router.

Here's what I did.  I bought a few of the adafruit boards https://www.adafruit.com/products/127 and then went to digikey and bought the buffer chip, power supply, capacitors and such.  I populate the board on what I plan on doing with it.  If I have 3v available, I don't need a power supply, if I'm using 3V logic I don't need the buffer.  See the trick?  In one instance I didn't need the board at all.

However, I did need a minimum of one usb adapter to the laptop and one fully populated adafruit board with FTDI cable on hand as I got into the project.  You can get by with the minimum of an arduino and a FTDI with the adafruit board because the arduino can be used to connect to the XBee.

The reason I have the USB adapter is to monitor the working XBees in action.  If I want to see what is going on, I plug in the usb adapter and just watch things happen.  If a person only has two of them watching one end perform is good enough, with more of them you'll want to see the various interactions and occasionally put something out to simulate something.

So far I have six XBees running around the house and never bought a shield.  I do have several adafruit XBee adapters and in one case I wired the XBee directly to the arduino.  You CAN hook an XBee directly to the arduino by using the 3.3V supply, ground and serial pins.  I have a device running just this way because I ran out of adapters once.  To secure them to something I use two sided tape, simple and cheap.  If you want to see the various items I've got running take a lock at my blog at draythomp.blogspot.com under the XBee tab at the top.  I even stuck one to the side of a wall wart as a temperature sensor.

You DO NOT need a complicated setup to get these to work.  I do recommend that you have two ways to connect the XBees to your computer so that you can run two of them at a time.  It's much easier to set them up and get them working if you can run two at once and play with the configuration.  Also, I don't always use arduino pins 0 and 1 to communicate with the XBees.  I use newsoftserial version 10C and put the XBee on a couple of digital pins.  This way I don't have to remember to unplug it to download software to the Arduino. 

cantore's technique is exactly what I use as well.  If you want to send several values just separate each of them with a comma from the last one and then the server can parse them out.

Holy Cow, that is so cool.  Interesting how insurmountable problems somehow get resolved once one's mindset changes.  I am very impressed at your efforts on this.  Now, the real challenge begins, how the heck are you going to make this look good on the front of the dishwasher?

Be sure to come back and post again when you get it finished.  I'm going to steal ideas.

This may not be the best way to do it but I convert the ints, floats, whatever to ascii and send it as text.  This has the incredible advantage of being readable when debugging.  I usually format the data into comma separated values (CSV) and the do a get with the values.  Over the wire it would look like "Device1,128,36.4,12" and the receiving end would parse out the values it wanted.

On a pc you can do a split() to have the data values separated, on the arduino there are other techniques that you can use.

Does any of this make sense?

Just a quick (hopefully) note on the other things that came out of this discussion:

Lefty you're right (pun totally intended) I have seen young people on this forum and others that I wouldn't recommend messing around with a 5V supply, much less something that can overcome skin resistance.  My problem was only with preaching that it was unsafe without an example or instance or anything.  That's what I ran into when I was reading a thousand or so posts on this kind of thing around the web.  Just, "Don't do it, it'll put your eye out" kind of statements.  I guess the "kid with the BB gun" in me can't accept that.

Your example of having to share a ground with the AC neutral is a good one as was Jack's of a hot chassis.  These are both problems that can be overcome relatively simply, but if one is going to ever share such a thing....beware of the uninformed.  The floating (voltage wise) arduino is another concern because someone will probably grab the arduino and the faucet at the same time; especially in a stainless steel, grounded refrigerator.  Sigh.

So, as I mentioned before, I'll bite the bullet and get a transformer, darn it.

In answer to some of the other questions.  Yes, you sample the instantaneous voltages over a power cycle as well as the current (going to use a hall device this time) and then integrate to get the various values.  You can measure the power factor and frequency of the incoming power to see what happens when you turn on the plasma cutter to cut a kink out of the tractor's fender.  I already do this for both phases of my home power using 200A current transformers wrapped around the mains input inside the circuit box (see, I'm not afraid of the voltage).  The calculations sound complex, but actually aren't bad at all.  My reading on an instantaneous basis rival the power company's expensive meters.  Yes, they've been out here explaining how they measure the power and comparing their results to mine.    Over time, their temperature compensation is better and my sums (of the readings) drifts from the KWH they record and I pay for, but not by enough to worry about. 

I've had county inspectors looking at it, people from the power company looking at how I did it and even energy conservation experts from a swimming pool company comment on it.  It was a really fun project that is ongoing (forever) and now I want to start applying it to smaller appliances.  For example, I have separate refrigerator and freezer.  Individually, they don't use much power and represent a minor expense, however with demand metering, if they both kick on at the same time, it drives demand usage up and I pay a ton for the small fraction of time that they operate together.  Hence, this project.  I describe this in horrifying detail on my web site at draythomp.blogspot.com.  I also have the various schematics and code that is running most of the devices I've incorporated into this project.  So, if you want to do something similar, grab anything you want and go for it.  Around my house, the current power usage is as easy to find as the time of day.

[That's it Jack, you nailed it.]

That's it Jack, you nailed it.  If I hook directly to the mains for my circuit, it will be fine until I turn the plug over.  Now, the hot side is in a different place and can cause some real problems. 

That's exactly what I was looking for and no one ever mentions.  Sure I could put a polarized plug with a ground pin on it to keep myself out of trouble, but if someone copied my circuit and didn't.....boom.  It isn't that its unsafe to do this, it's like you said, someone else won't take the care that I (hopefully) did in setting it up or modifying it.  There are ways of avoiding the problems you pointed out (excepting lawyers), but it's hard to make something foolproof; fools are too resourceful. 

Thank you.  I guess I'll go look for a really small power transformer that I can use to sample voltage and leverage it as a power supply for the rest of the circuitry.  The hall effect device will still be in the mains circuit, but it's optoisolated, doesn't care which leg it's in and UL rated to 3KV.

Found it!  You probably have the correct library.  There is a configuration parameter in the file apps-conf.h and you have to select WiServer for this.  The part you want is up at the top and looks like this:

Code:

//Here we include the header file for the application(s) we use in our project.
#define APP_WEBSERVER
//#define APP_WEBCLIENT
//#define APP_SOCKAPP
//#define APP_UDPAPP
//#define APP_WISERVER

comment out the APP_WEBSERVER and uncomment APP_WISERVER, then you should be fine.  I did that so long ago that I forgot about it.

Just tried SimpleClient and it compiled correctly.  You probably already did this but, did you restart the IDE after putting the library in place?  The development environment has to be shut down and started again so it will notice that there is a new library in place.  I've made this mistake a couple of times and gotten the same kind of message.  Another possibility is that the library you picked up has a problem, you may need to hunt down a later one; maybe at the asynclabs web site.  I got mine there.