Does anyone have a recommendation, or should I just ditch this one and buy a W5100?

@Si

I've tried using your ETHER_28J60 library, but I get several errors when trying to compile it.  I'm not sure how to troubleshoot this.  I'm far from an expert in C.  Dueminalove with 168, Arduino 18 environment, etherShield library, ETHER_28J60 library, ENC28j60 ethernet module.

Code:

C:\Program Files\arduino\arduino-0018\libraries\ETHER_28J60\ETHER_28J60.cpp: In member function 'char* ETHER_28J60::serviceRequest()':
C:\Program Files\arduino\arduino-0018\libraries\ETHER_28J60\ETHER_28J60.cpp:79: error: 'class EtherShield' has no member named 'ES_make_arp_answer_from_request'
C:\Program Files\arduino\arduino-0018\libraries\ETHER_28J60\ETHER_28J60.cpp:108: error: no matching function for call to 'EtherShield::ES_make_tcp_ack_from_any(uint8_t [501])'
C:\Program Files\arduino\arduino-0018\libraries\EtherShield/EtherShield.h:51: note: candidates are: void EtherShield::ES_make_tcp_ack_from_any(uint8_t*, int16_t, uint8_t)
C:\Program Files\arduino\arduino-0018\libraries\ETHER_28J60\ETHER_28J60.cpp: In member function 'void ETHER_28J60::respond()':
C:\Program Files\arduino\arduino-0018\libraries\ETHER_28J60\ETHER_28J60.cpp:158: error: no matching function for call to 'EtherShield::ES_make_tcp_ack_from_any(uint8_t [501])'
C:\Program Files\arduino\arduino-0018\libraries\EtherShield/EtherShield.h:51: note: candidates are: void EtherShield::ES_make_tcp_ack_from_any(uint8_t*, int16_t, uint8_t)

I would visit www.cnczone.com.  The forum has information on just about anything you want to buy/build.  I built a cnc router for about $500US.  The cutting area on mine is 24" x 36" and 6" height.  It's not a fast machine, but it does a nice job.  I built a Sosylva machine.  The most expensive parts will be the stepper motors, motor controllers, and power supply.  Good luck!

I would suggest looking into using interrupts.  Unfortunately, I don't have any experience in using interrupts so, hopefully, someone who can provide some good knowledge will step in and add some details.

In the interest of being cheap, I want to do away with the mechanical water meter and timer on my water softener.  I want to use Arduino to control the valves, cycle timing, and cycle rate --by measuring water usage-- and convert it to electronic control.

What about taking a wire and making a few wraps around the plug wire, feeding it to a small circuit containing a 5V zener diode, then to the micro.  This should induce a voltage, the zener would keep it low enough for the input to the micro, and you should be able to measure the timing between signals.  The only issue I can see here is with engines that us a wasted spark ignition method.

Wow, you could nearly replace the whole furnace for that price.

Hope you got your furnace fixed. Used to work on them for a living. Work for a manufacturer now. I know how much of a bind that can put you in. Can be expensive too.

I have personally built a cnc router and I think you may want to get some more threads per inch.  The 1/4 inch rod is probably appealing, but the 20 TPI will cause issues with travel times and weak torque on your motors.  The faster the stepper motor turns, the lower the torque it can provide.  I am currently looking into changing my rods to a more coarse thread for faster travel.

All of that being said, the goal is to keep the project under $100, so I understand if speed and torque are not of prime concern.

@lefty--how true it is!

Barish,

I understand what you're saying about the temperature of the radiator feed water, but I think you could probably do it by using a PI loop to determine how much heat is required, rather than the outdoor temperature.  With a PI algorithm, you can decide how much heat to add by measuring how far you are from the desired temperature and how long you have not been at the desired temperature.  The outdoor temperature would affect how fast you drift from the desired temperature, but you would probably need to determine experimentally how much gain to add based on the outdoor temperature.  A PI would do this automatically, and without the need for the outdoor temp.  Food for thought.

The same is true in Aviation.  English is the spoken language for airlines.  Yes, there are people who are multi-lingual, but if you want to fly the big birds, you must speak English.

I'd suggest looking at this post: http://arduino.cc/forum/index.php/topic,8721.0.html
I finally got it working at my house this weekend.  The Apache server configs need some massaging to get it to work, but I can give you some details.  I have a password protected website with my Arduino remote control webpage behind the login.  My test setup was to put an LED on the Arduino and use the webpage to turn it on and off.  I plan to move toward controlling other things, like lights (lamps), possibly garage door, etc.  I don't know how to do any visible feedback on the webpage.  I may look into doing something like that as well, although it isn't my main concern.

There is one gauge that I might suggest.  There is a guy that used to write for kitplanes magazine and I saw this:
http://www.rst-engr.com/kitplanes/KP0006/KP0006.htm
http://www.rst-engr.com/kitplanes/KP0007/KP0007.htm
http://www.rst-engr.com/kitplanes/KP0008/KP0008.htm

I think it's a very nice solution, AND, you won't have any chance of ignition if you follow their suggestion and coat the plates.  Have a look.

You could use something like this to determine if the go button is not released.  Once the button is released, it changes the value of go_button_pressed.  When the value goes from 1 to 0, the program starts on your PC.

Code:

              if((go == LOW) && (last_go == LOW))
                  {
                     go_button_pressed = 1;
                  }

              if((go == HIGH) && (last_go == LOW))
                  {
                     go_button_pressed = 0;
                  }