Is this Bluetooth module cool for Arduino? I am making a basic project that will have 4 or 5 arduino nodes. Each arduino will have a bluetooth module attached. The thing I want is, I want to be able for each one of these arduinos to know the other is present in the room (let's say, 5 meters). For my experience in the cellphone, I don't even have to pair bluetooth devices to know about their presence, as long as they are in visible mode. Since I just need to know their presence, and no exchange of information will ever happen, I probably will never have to pair them right?

For this project I need a bluetooth (BT) module that:

1) Enables me to change the ID of each arduino, so that, even if I use my cellphone to scan for BT devices I will see (Arduino1, Arduino2, etc...) instead of default-factory-names.

2) Enables me to scan around for existing devices every time each X seconds, because I want each arduino to know if the others are in the room.

Will this module do the trick? http://www.ebay.co.uk/itm/Interface-Base-Board-Serial-Transceiver-Bluetooth-Module-For-Arduino-UNO-R3-/111482008102?pt=UK_BOI_Electrical_Components_Supplies_ET&amp;hash=item19f4d87226

Later I will probably hang around with batteries so I will want a low power BT module, having the same 2 capabilities mentioned. Will NRF8001 do the trick for me? http://www.nordicsemi.com/eng/Products/Bluetooth-Smart-Bluetooth-low-energy/nRF8001

Thanks!
From skimming that post, I believe that your linked pcb is not a full bluetooth module (note how there is no bluetooth chip or antenna of any kind). This is simply a "base board," which is why it is so cheap1.

You will need something like this that actually has the components you want.

To answer your questions:


The bluetooth library for arduino sets the discoverale name to ARDUINOBT by default, but that can be changed in the setup() method.  
"scan around" is a little ambiguous—AFAIK, bluetooth can only connect to one device at a time, but I'm not sure if that's totally true. You may want to look into using radios instead of BT, as they can communicate more freely with one another, are extremely cheap, and have extensive arduino libraries availible. I'm currently working on a project that uses the nRF24L01, and I'd be happy to answer any questions you have about it.


1: It also has a draw of 6v VCC, which is more than the Uno can output.