Questions about the wifi shield and relays

Hey guys so I bought an arduino UNO for my project I am working on. Basically what I want to do is control certain 12v circuits that are in my car using an android device that I have fiberglassed into the vehicle. I will be controlling Mostly leds I have installed in the cabin. Anyways I was originally gonna do it over bluethooth but was told it would be easier to do it over WIFI. My main question is, do I not need an internet connection to be able to control the circuits? As stated It will be in my car, so I do not have acess to any internet so how does it work? Does the wifi shield act as a router? Am I able to connect over wifi to my arduino withought internet? I am really confused on that part. It seems like a good idea as I know html and could design a cool layout for the phone to display the buttons etc..

Also I imagine I need 5v relays?

I have an 8-relay shield that plugs onto an Uno for controlling things like you describe.

Here’s a clip of it driving 8 AC powered LED strings

The relays are controlled by a shift register can connect it to any 3 pins to control it.

Bluetooth seems the right choice for you.

In a home network, an Arduino Uno with Wifi Shield can be just another IP number in your home network. In a home network is easy to have everything in the network: computers, tablets, Arduino boards with Ethernet Shield, the Arduino Yun (with wifi included) and so on.

Controlling a single Arduino with a single computer (or tablet or phone) is a job for Bluetooth.

I have a board for Mega’s also, controlled by 8 discrete outputs instead.

@crossroads How much for the board? I'm assuming each relay can be controlled individually?

@Peter_n The reason I like the wifi idea, is because I can design a nice website with buttons as my goal is to have the phone look like an onboard navigation type unit. If I go with bluetooth I'd imagine I would be limited to what I can do, as I have no clue how bluetooth works.

So the wifi would work though, or I do need a internet connection? I thought with wifi, I'd have acess to onboard files and be able to comunicate with the phone and android.

I think $32 plus USPS shipping and paypal fee.
It uses these relays

plus the PCB, the headers, shift register, LED/resistor/diode per relay,
some of my time to mount all the surface mount stuff.
Kinda pricey compared to the modules found on ebay, but those seem to be hard to understand, lots of confusion on driving them, plus an IO pin per relay; vs 3 pins for all 8 - simple shiftOut() or SPI.transfer() command to turn them on/off, and indicator of on/off state. Plug it on and go.
I don't expect to sell many of them. Can't really compete with mass production & cheap or automated labor.

Thanks for the info! I'll make sure to keep you in mind. I just really need to figure out how I am gonna control the arduino/relays. Hoping someone can answer my wifi issue. From what I understand, I don't actually need internet, I can still comunicate over wifi to my arduino and run everything off an ip and have the website files stored on the sd? Or do I actually need an internet connection to be able to controle anything.