Ethernet Shield reluctant to connect

[G+_Dan Jeffrey]

Ethernet Shield reluctant to connect. I have an Arduino project that opens and closes my garage door when I click a link in a web page (local network only). It works but the Arduino web server is tempermental when I have the thing in the garage. If I connect it near to my router, then all is well.

 

1. Does the longer run of Ethernet cable require more power to the Arduino?

2. What is the best power to feed it? Most of the Arduino power adapters appear to be 5Volt 1Amp. Is that enough? Would it help or hurt to use a 2 Amp power source?

3. If I go with PoE, can you recommend a brand of PoE "adaptor" to use (the thing that has a power brick, connects Ethernet device to a router, and sends power out to the device).

[G+_Fr. Robert Ballecer, SJ]

The Shield CAN be temperamental and I've found that it doesn't like certain switches. (For example, the won't work AT ALL if I have them behind one of my intellijacks.)

 

Is there a switch between your router and the garage? A longer run doesn't need more power.

 

A 2-Amp power source won't hurt it... the device will only draw as much as it requires. (That's NOT true of voltage... more voltage CAN kill your project.)

 

If you're going PoE, anything that conforms to the IEEE 802.3af-2003 or better should work just fine.

[G+_Travis Hershberger]

I've got a PoE adapter at home waiting for me to break out the Pi. Guess you have me a reason to. Don't remember what brand it is, but it is a 2.5 Amp.

 

Amp wise, more is fine, unlike voltage where you release the magic smoke. Might be good to figure max amps drawn by all your accessories. I think the minimum for a Pi is 500mA. It should be listed somewhere.

[G+_rick rangel]

A bit off topic, but I was toying with the idea myself. Would you mind telling what your setup is? Thanks.

[G+_Dan Jeffrey]

Yes, Padre! I had it connected through a cheapo Netgear 4-port (maybe 5?) switch and then into my main switch. I can run PC's through that switch. Come to think of it, I had problems with other things like Beagle Bone and Raspberry Pi -- I kind of gave up on them.

 

The switch issue would explain a lot of problems. Thanks a lot Padre!

[G+_Dan Jeffrey]

Sure rick angel -- I have an Arduino UNO with Ethernet shield. I have a couple of LED's to show me connection status. And I have code that puts out a web page by default -- that links to another URL that simply toggles the garage door. This is all in a bread board today.

 

For controlling the door I simply drive a relay with a binary Arduino pin. I used some cheap speaker cable to wire the controlled part of the relay circuit in parallel to the main garage door opener button.

 

I had some trouble with "bounce" -- or something like that. The door would open and close multiple times for one web click. I think that could be fixed with adjusting the time I leave the relay circuit high in the Arduino. Or maybe I need a pull down resistor on the relay for the LOW signal.

 

Does all of that make sense?

 

Next Steps:

1. Add a sensor that knows when the door is closed. A simple boolean the program can use to be sure it has done it's job. Then I'll make logical "open" and "close" operations that will work from the web page regardless of where the door is to begin with.

 

2. Add an indicator of door status on the web page (or a graphic would be cooler!)

 

3. Add some layer(s) of security -- some kind of challenge/response on a server that then talks to the Arduino in some encrypted way. Gotta figure this out still.

 

4. Figure out the electronics inside my garage door opener. Hopefully I can use the power that's there to drive my Arduino. If not, I'll just add a wall wart for it. This step is not important though because I can hook into the opener circuit anywhere along the wire.

 

After that, my sprinklers are going to get a new controller. I love this stuff!