Hi All,
As I told before, here I am coming with second implementation which is very basic implementation. In fact I made this in very short time and posting it. I thought of improving and making complete Karaoke based on web and service running on Raspberry Pi, but as short of time I could do only basic playing song, stopping song and show lyrics features.
Concept Overview-
In this concept in order to use Wolfson Card to make Karaoke Player, I could not use Pi Face control display, As it could not stack on Wolfson module. Also as in first demo, I didn't want to make Karaoke Player dependent on big screen like TV/Monitor. So in this case Making a Karaoke player for which we can use mobile as User interface and Raspberry Pi as Processing device was better idea for me. Hence I installed apache webserver on Raspberry Pi, also made Raspberry Pi to act as Access point so that I can connect mobile to it to access webserver pages, and wrote a small php script (As I am from electronics background I was new to it) to control songs and lyrics.
You can find demo video here
Rocking Raspberry Pi Challenge demo 2 (Wolfson Audio Card and Basic Karaoke)
Implementation details-
Wolfson Card Setup with Raspberry Pi-
To setup Wolfson card I did some search and then found that the official image for Wolfson Card was too big, that could not fit into 8GB SD card. Hence I came across following link
where Ragnar jensen provided precompiled kernel image, driver modules and shell scripts that are in official release. Thanks Ragnar Jensen for it.
This made the work easy and saved driver/kernel compilation time which I was going to do.
I just downloaded the tar file provided on above link which you can find at
https://drive.google.com/file/d/0BzlaxMH3N5O1RnJfcGVpdmY1T1E/edit?usp=sharing
Download the tar file from above link and just extract it in root folder "/"
cd /
sudo tar -zxvf /tar_file_path/kernel_3_10_25_wolfson.tgz
After that your new letest kernel which contains wolfson driver will be there under /boot/kernel_wolfson.img, hence in order to
instruct Raspberry Pi to boot this new kernel from next time you need to mention it in /boot/config.txt file like
add this line "
kernel = kernel_wolfson.img
" in config.txt file.
and then reboot this will enable driver support in kernel when raspberry pi boots on wolfson kernel provided.
You can download manual about Wolfson card from www.element14.com/wolfson
for further test you can refer user manual for Wolfson Card.
Note: I found as Wolfson card connects Raspberry Pi on Pogo Pins sometimes connections are not proper, and you won't hear sound even you detect the wolfson card. So I suggest if you find any problem with working of Wolfson card please check your pogo pin connections are proper or not. Better use screw with the plastic piller which is mounted on Wolfson Card.
Now once your Raspberry Pi rebooted with new kernel, you can play with Wolfson card. In this case Wolfson Audio Card will be having card 0 hardware address and bcm (default audio card) card will be having hardware address 1. So you can use this address in order to access respective card.
In order to set the Input/Output which you are going to use,Wolfson provided use case scripts which you can find in /home/pi/use_case_script. I tried Playback_to_Headset.sh, Playback_to_LineOut.sh, Playback_to_Speakers.sh to play audio out on headphone, line out and loudspeaker connectors respectively.
you can play audio with following command
aplay -Dhw:0 -r 44100 -c 2 -f S32_LE <file>
In order to record input from any input you can use
arecord -Dhw:0 -r 44100 -c 2 -f S32_LE <file>
In my implementation I am using DMIC input using above mentioned command when I play song from web browser.
Setting Raspberry Pi as Wifi Access Point-
I refered Online resources for setting up this.
Following are the steps to make Raspberry Pi as Wifi Access Point with WiPi Wifi Module
Install following demon to make it Access point and DHCP server so that it can provide IPs to connected devices
sudo apt-get update
sudo apt-get install hostapd isc-dhcp-server
Setting up dhcp server configuration
open DHCP configuration file to change settings
sudo vi /etc/dhcp/dhcpd.conf
then comment following lines
option domain-name "example.org"; option domain-name-servers ns1.example.org, ns2.example.org;
like this
#option domain-name "example.org"; #option domain-name-servers ns1.example.org, ns2.example.org;
Also find
#authoritative;
and remove comments from it (remove #).
Then save file and exit from file.
Then run
sudo vi /etc/default/isc-dhcp-server
and find INTERFACES="" and make it INTERFACES="wlan0" so that DHCP server will work on wlan interface.
Then run
sudo vi /etc/network/interfaces
and edit file
Find auto wlan0 and comment it by adding # in front of it.
Also comment following lines
#iface wlan0 inet static
#wpa-roam /etc/wpa-supplicant/wpa_supplicant.conf
#iface default inet dhcp
and add following line after "auto wlan0" to set static IP to WLAN0 interface
iface wlan0 inet static
address 192.168.1.1
netmask 255.255.255.0Save and exit.
sudo ifconfig wlan0 192.168.1.1 which will be AP and DHCP server address.
Now configure access Point details by creating new hostapd config file
sudo vi /etc/hostapd/hostapd.conf
You can edit
ssid="yourid" and wpa_passphrase="yourpw"
as per your requirements.
Also make
driver=nl80211
Save and exit.
then open
sudo vi /etc/default/hostapd
find #DAEMON_CONF="" and uncomment and edit it to access hostapd.conf like DAEMON_CONF="/etc/hostapd/hostapd.conf".
Then start both hostapd and DHCP server service.
sudo service hostapd start sudo service isc-dhcp-server start
Then you must be able to connect your mobile to Raspberry Pi.
Install Apache server and php on Raspberry Pi
sudo apt-get update
sudo apt-get install apache2 php5 libapache2-mod-php5You can edit permissions and user groups from /etc/apache2/envvars
PHP script to play song and show lyrics placed under /var/www/ folder-
<html><body><h1>Raspberry Pi Karaoke Player!</h1>
</body></html>
<?php
if (isset($_POST['Lyrics']))
{
echo file_get_contents( "lyrics.php" ); // get the contents, and echo it out.
}
?>
<?php
if (isset($_POST['button']))
{
echo 'Playing song';
system('mplayer -vo null -ao alsa /home/pi/Karaoke/devashreeganesha.mp3 ');
}
?>
<html>
<body>
<form method="post">
<p>
<button name="button">Play Song</button>
</p>
</form>
</body>
<html>
<body>
<form method="post">
<p>
<button name="Lyrics">Show Lyrics</button>
</p>
</form>
</body>
<?php
if (isset($_POST['closebtn']))
{
echo 'closing song';
system('killall mplayer');
}
?>
<html>
<body>
<form method="post">
<p>
<button name="closebtn">stop song</button>
</p>
</form>
</body>
I hope the implementation details I gave should be fine. I thought of implementing more but as time was short I couldnt. I will update same demo even after this challenge. Kindly let me know if I am missing something in here.
Thanks Element14 for giving me such opportunity.
Thanks,
Shrenik Shikhare.