Can you guys recommend a shield for me? I'd like to pay no more than $60 for a wifi shield. What I need to do is have a mobile phone communicate with the arduino. This does not involve internet. This is a straight connection from the phone to the arduino. I am able to do this now by using an ethernet shield, and a home router. I would like to cut out the router and use a shield like the xbee. I need the shield to act as a router where I can easily connect my phone to it. I also need the arduino to know the wireless strength of the connection so that I can complete actions when the strength goes above or below a certain value. This is for an arduino uno but I also have a mega that I can use. The arduino acts as a server. Open to any recommendations.
I presume a bluetooth shield would be necessary in your scenario,
something similar to the one here : Bluetooth Shield | Seeed Studio Wiki , what would follow next is an android app running bluetooth which there are tons available, especially on google API's page which help in customising your app for your PAN network. This way through your phone you just open up the app, which in turn would override the phone's bluetooth operation and establish comms with the arduino/device.
Although I haven't enough info on your scenario and with my limited experience, I would presume having the device operate off a battery, even so, it would afford utilizing sleep mode, and awakening the device using the app, preserving power and the component's "lifetime".
The reason I did not choose blue tooth is because of the range. Wifi has more range and the goal is to have a long range (100ft+?). I did have it set up for bluetooth but I was only getting a range of about 50ft through one wall. If there was a shield that would allow me to connect via bluetooth at greater distances and perhaps through more walls, that would be fantastic. Wifi seems to travel further and better through walls which is why I chose to go that route. Maybe you guys could give me some insight on that.
The only communication is between arduino and mobile device. All I have is an ethernet shield which I am going to replace with a wifi shield. The ethernet shield will no longer be of any use. The arduino will have a wifi shield ( or bluetooth if I can find one with a range of at least 100ft through a wall or two ) and the mobile device will connect to that shield and communicate back and forth with the arduino.