List of parts used:
Raspberry Pi Model A
wireless usb adapter (based on RTL8192cu chipset)
usb to micro usb cable
3.5mm audio to 3.5mm audio cable
2GB or larger SD card
12v USB power adapter (maybe depends on car)
Raspberry pi case (built or purchased)
Here is the link to download the image https://dl.dropboxusercontent.com/u/6715184/minipi.7z
. Windows users will need 7-zip to expand the image and then use win32-diskimager to write the image to a 2GB or larger SD card.
This is based on latest raspian image, is setup for US keyboard and locale, is overclocked to 800mhz and has memory set to minimum amount for GPU. Uses default user and password of pi and raspberry .
The default SSID is MINIPI and password is DontBlink .
The files you will want to edit are as follows:
/etc/hostapd/hostapd.conf - where you configure the SSID and password for the wifi network
/etc/init.d/shairport - where you set the name of the airplay receiver.
You can edit these files after the pi has booted by joining its wifi and connecting with ssh. I use iSSH on my iPad to do any tweaking. Using putty on a windows laptop or desktop (with a wifi adapater) works just as well.
I have a 2009 MINI Cooper and wanted to add the ability to stream pandora from my iPhone to my car. The car has bluetooth but doesn't support A2PD for streaming. The car does have traditional iPod support and an AUX in port. So having a model A pi sitting on the shelf needing a project I set out to solve the problem. I had found other projects with similar goals but many of them require you to use your phone or tablet as a hotspot. I wanted to avoid this as many service providers including mine charge an insane monthly fee for the ability to use this built into the OS feature. First I got airplay (shairport) working on my local network and tested the sound output. The original build using the master branch of shairport had mixed results. I switched over to the dev-1.0 branch and found the sound output was stable and used less cpu/memory. Next up was to make my wifi adapter based on the RTL8192cu chipset work as a hotspot. After following 3 different guides I was able to connect to the pi as a hotspot, but airplay/shairport would not work. I tried many things trying to find the magic combo to get it work with no luck. Then one day I stumbled across this guide http://learn.adafruit.com/setting-up-a- ... t/overview
on adafruit. There were two things different in this guide than the others I had followed. 1. Using the pre-built binary from adafruit instead of building from source. 2. Removing WPASupplicant. These changes fixed the issue and now using airplay was as simple as joining the pi based wifi and picking the airplay receiver from the app. It took some experimenting but I figured out that as long as I don't send a DNS server address to the device I can still use my cell data to pull in Pandora or other streaming music while sending it out over wifi to the pi.
The main parts of the project now working I started testing to see how stable the setup was and what kind of issues I might see in use. After this testing I found that at times running without a keyboard the wifi adapter would not properly start and as such the hostapd and dhcp servers could fail. So I made some changes and have all the services start in the proper order at the end of the boot process using /etc/rc.local file. I have tested this setup on 2GB class 4 SD cards through 16Gb class 10 cards on 256MB model B, 512MB model B, and Model A Pis and feel the setup is stable enough to release out into the wild.
I use iSSH on my iphone with a connection setup for the pi and sends the command "sudo init 0" to gracefully shutdown the pi when I remember. I have not had any problems so far in the 3 weeks of use in car with a corrupted SD card. In the car I use the built-in usb port which powers on when I open the door and shuts down with the external lights after exiting the car. I built a case using the container an iPod touch came in with a little dremel work, some superglue and plastic standoffs. I plan to add a push button or toggle button to gracefully power down the pi in the near future.