Sensor to check if a equipament is connected or disconnected

Well, In my project i must have a Software WEB (Java) that receive a information from Aurduino, this is information is the ID of Equipament (i.e: 1003) and a signal if this equipament is connected or disconnected (i.e: if a refrigerator is ON or OFF).

When my software web receive this signal saying that a particular equipament is "ON", the software starting a clock that will determine how much time this equipament was connected, until someone disconnect (turn off).

The problem is:

1 - I need a sensor to determine if a equipament is ON or OFF (i.e: refrigerator, air conditioning, television and others). Which sensor can i use for this propose ?

2 - I need a arduino connected in this sensor, that will receive information from sensor and send to SOFTWARE WEB. I need a protoboard to this connection between sensor and arduino ?

3 - My arduino must send the information received from sensor to my SOFTWARE WEB, how kind of Arduino Board i should buy to send this information through INTERNET ? (Better is Wireless, but if this arduino is very expensive i can use a Ethernet Cable just for test), so give the 2 models please.

4 - I imagine that i can't have a BIG KIT (Arduino + sensor + protobard) because this will be plugged in a JACK and should be as small as possible.

  1. Use this sensor to determine if/how much current is flowing through an AC power cord.

  2. This will require a breadboard circuit. Read through the description and comments of the product page in the link above to see how to get it hooked up to an arduino.

  3. There are Arduino shields for both wired and wireless communication. Buy one and attach it to your Arduino.

  4. You can make this thing pretty small, maybe about the size of 3 decks of cards stacked on top of one another.

I didn't understand the item 3:

"3 -There are Arduino shields for both wired and wireless communication. Buy one and attach it to your Arduino."

I should buy a arduino and after a arduino shield ? Can you give me some example more simple ?

A shield is simply an add-on board for an Arduino. So you would have your Arduino (say an Uno for example) that interfaces with the sensor and processes data from it. The ethernet and wireless shields are simply another board that you attach on top of your Arduino that give it ethernet or wireless capability. Here is a picture of a wireless shield on top of an Arduino Uno.

Does that make sense?

Right, now i understand but:

1 - Which arduino i should buy for my project (specification, as you said UNO) ? 2 - Wich "add-on" (specification) i should buy (wired and wireless) ?

You are probably best getting the UNO. It's not the smallest Arduino (the Micro is), but the UNO will fit best with the shields.

In terms of the shield, buy one of the ones I sent you in the original link. If you go to those links and look right below the pictures, there are buttons for buying from the Arduino store or buying from other distributors. Just pick if you want to go with ethernet or wifi.

Here are the links again for your convenience:

For wifi, buy this shield:

for ethernet, buy this shield:

So, i should buy this itens for my project:

1 - Arduino UNO: 2 - Arduino Shield Ethernet: 3 - CT Sensor: Didn't find yet, in BRAZIL Store. 4 - Protoboard:

My buy list is right ?

Looks good to me!