How to Add AirPlay to Your sportsCar for High Quality, Wifi Audio

I was fed up with having so many cables floating around in my car and getting tangled, and I wasn’t happy with the compressed audio quality with Bluetooth. So, I came up with an awesome wireless audio solution. If you're bold enough to pop open an Apple AirPort Express and modify its innards, here’s how to hack Apple AirPort Express to put AirPlay in your car. P

Note: Ben's original has been edited down a bit to clarify things for the non-technically-inclined, so if y
ou want the original version, go here.P

Requirements:P

AirPort Express: $99
P
Car with an aux input in the stereo and a free “cigarette lighter” power plugP
Star/Torx screwdriver: $8P
Regular screwdriver: you probably already have oneP
USB cable: we all have spares of these too!P
Some standard wiresP
5V to 3.3V DC stepdown converter: $4P
A soldering iron & some solder: $8P
Super glue: $5P
Cigarette lighter-to-USB converter: $5-$15P
A little electrical tape: $5P
1. Open the AirPort ExpressP

Okay, deep breath. First, you’ll need to modify the AirPort Express so that it draws power from a USB cable, instead of its usual household plug. In this post in the North American Subaru Impreza Owners Club forum, user “enjoiful” describes one technique for this. (You might want to check out his or her photos too, for help with this part). Basically, to pop open the AirPort Express, stick your regular screwdriver in the seams at the corners and try some twisting and prying motions. It should pop open easily.P

2. Deal with the BoardsP

Unscrew all of the circuit boards from the AirPort Express. You can get rid of the L-shaped power supply, because we’re going to wire the USB power to the 5V-to-3.3V converter and use that instead.P

3. Open the CableP

Cut the USB cable, and peel the wrapping towards the larger plug (the one that normally connects to your computer), because you want to keep that side. This will reveal four wires:P

Green: USB DataP
White: USB DataP
Red: +5V DCP
Black: GroundP

4. SolderP

We're only interested in the red and black wires inside of that USB cable, because there’s no data coming over the USB cable. After threading the wires through the hole in the side of the AirPort Express (pictured above), solder the black one onto the ground of the AirPort Express (see photos below).P


Then, connect the red one to the VIN (voltage input) wire of the stepdown converter, which is green in this photo, and tape around that connection like this:


5. Super GlueP

You’ve made it through the hard part (hopefully without melting your brain or burning down your house). Congratulations! Now, you’ll want to super-glue everything into place so that it doesn’t jiggle around, potentially causing the solder to break, as you drive over your city’s pothole-riddled streets.P


6. Snap It Together and Tape Over the HoleP

Snap the AirPort Express back together. Then, use another little bit of electrical tape to seal up the hole on the edge of the AirPort Express, so that dirt and dust doesn’t get in there, like so:

7. Connect It to Your CarP

It’s time to use this thing. Put it in your car, connect the USB power cable to a cigarette lighter adapter, and plug that into your car.P

Then, take the audio cable that came with the AirPort Express and connect that to your car’s input. But wait! You’re not done yet, because you’ll need to set up the AirPort Express and your iPhone or iPad the right way (or Android, because those can totally support AirPlay, as weird as that is).P

8. Configure the AirPort ExpressP

This looks a bit convoluted, but it’s not, and you only have to do it once.P

With the AirPort Express powered up and running, fire up Apple’s AirPort Utility on your laptop, in the car. (You can also do this before tackling any of the steps above, but we wanted to make sure you make it this far before bothering with the software tweaks.) AirPort Utility will display your modified AirPort Express in a list similar to this:

Click the device and select "Edit." First, give it a name and a password so you can connect to it later to configure it.P



9. Configure your iPhone or iPad (or Android)P

How to Add AirPlay to Your Car for High Quality, Wireless Audio
You need to make your iPhone, iPad, or Android connect to the AirPort Express to send music, but to the cellular data network for everything else (including streaming music). We’re going to walk through the instructions for iOS here; Android people using these apps or these ones can apply similar principles on that platform.P

Open the iOS Settings menu, tap WiFi, and tap new AirPort Express network. This will connect the iPhone or iPad to your new car-based WiFi network — but you’ll find that because the AirPort Express doesn’t have an internet connection, the internet won’t work on your phone. But we can fix that. Tap the blue arrow next to the name of the AirPort Express WiFi network to view more options.P

From the screen (pictured at left), select "Static" as the type of IP address, and then enter the following IP address and Subnet Mask :P

IP Address : 10.0.1.4 (for example)
Subnet Mask: 255.255.0.0P

Make sure you leave Router, DNS, and Search Domains blank! This tells the iPhone that it should use its cellular network to route internet traffic rather than trying to do it via WiFi.P

And you’re done! Just one thing to keep in mind here though: When you’re connected on your AirPort Express WiFi network, the data icon at the top of your iOS screen won’t look like the WiFi network symbol, the way it normally does when connected to WiFi. Instead, you’ll see the cellular icon—E, 3G, 4G or LTE, depending on your data plan. Never fear, your phone is actually connected to the WiFi network for the purposes of AirPlay, just like we want it to be.P

source