Wow - I was just logging in to ask about the details on if anyone had tried sending data from the gateway to sensors and here we are. This is great! I was looking to light up a LED when sensors tripped, but now I must send text to an LCD for a "real time feed" of what my sensors "see" or "know". I may need one of these by the arm chair in the den now that it can tell me useful stuff!

As to mounting and placement (not sure if NOTYETRATED was asking more along the lines of this context), I am mounting both Unos and Pro minis in standard light switch boxes (plastic electrical junction box). They are cheap and easy to "blend in" with a faceplate that matches everything else in my house that was built in the 1960's. I have several in my house that are duplex boxes where we are only using one switch, so I have the extra space for mounting a sensor and battery pack. An uno and batteries are pretty tight - I don't have any of these mounted "in production" yet. A mini pro mounted via "3M VHB Tape" (Very High Bond - stickiest tape I think ever made) works well.

Now to see about cutting a blank switchplate to mount an LCD, add a button and voila'! - weather by the back door to the garage!

Just FYI - I am using one of the ethernet shields like this one: ENC28J60(one of the "HAN RUN" cheap cards - my serial number on the part is the same, the "date code" looking number is different, though). What I found through trial and error was that when I was using the radio AND the ethernet shield, my 3.3V pin could not power both, so the ethernet card would not properly initialize. I finally figured this out by using an "arp -a" on my linux system and noticed that the DE:AD:BE:EF:FE:ED mac address always showed up with an IP of 0.0.0.0 even though it was hardcoded into the sketch.

The solution? This card ls 5V tolerant. I put my radio on the 3.3V pin, the ethernet on the 5V pin and my problem was solved - the card initializes properly every time. My radio on the gateway has also been a lot more stable (still using a 4.7uf cap, though).

To be clear - I am NOT saying just plug any card into 5V and expect it to work. Do check out the specs on your card, see if it is 5V tolerant and if you are willing to accept the risk and try it, it may be something to look into. I also recommend you turn on debug like Hek recommended. That helped me a good bit as well see where things were getting hung up on other sensor issues after I got past the ethernet issue...

Good Luck!

For an ethernet gateway, I have an Arduino MEGA 2560. Here is the pinout I have working:

• MEGA *
• ----------- Connection guide ---------------------------------------------------------------------------
• 52 Radio & Ethernet SPI SCK
• 50 Radio & Ethernet SPI MISO (SO)
• 51 Radio & Ethernet SPI MOSI (SI)
• 53 Ethernet SPI Slave Select (CS) Pin 53, the SS pin, must be an o/p to put SPI in master mode
• 9 Radio TX LED using on board LED (optional) +5V -> LED -> 270-330 Ohm resistor -> pin 9. ********
• 8 Radio RX LED (optional) +5V -> LED -> 270-330 Ohm resistor -> pin 8. ********
• 7 Radio error LED (optional) +5V -> LED -> 270-330 Ohm resistor -> pin 7. ********
• 6 Radio SPI Slave Select
• 5 Radio Chip Enable (CE)
• 3 Inclusion mode button (optional), 10K pull down to GND, button to VCC) ********
• 2 Radio IRQ pin (optional), W5100 Int, if linked to pin 2) ********

• ---

• Powering: both NRF24l01 radio and Ethernet(ENC28J60) uses 3.3V
  The ********* were just a visual reference for me on the "optional" pins since I was not using them in testing.