Raspberry Pi for Theater

Raspberry Pi: Live @ The Brick Box

I was helping with a Theater production at the Brick Box here in Rutland, Vermont. I was in charge of running the lights and sound, but the only sound they needed for the show was a telephone ring. I could have looked online for a phone ring device designed to be used in theater, but instead I decided to use a Raspberry Pi to get the job done. Here is how I did it.

First off, I was going to be in the back of the audience, and the phone ring needed to come from behind the stage. So I needed a way to have my Raspberry Pi Setup back stage, but be able to control it from the back of the theater. I decided to set it up as it’s own wireless access point, with DHCP server. To accomplish this, I configured the wireless adapter on the Pi with a static IP address of 192.168.42.1, and installed a program called hostapd. The hostapd program allows you to broadcast an SSID (name of network for other devices to see and connect). Then I edited the config files to use the name I wanted for the network, as well as set a password, so only I would be able to connect to the network. I also needed to install  isc-dhcp-server which allows the Pi to act as a DHCP server, and assign IP addresses to any device that connects to the Pi’s wireless access point. After all of these were install and set up properly, my Pi was ready to run headless (without a monitor connected to it).

To set up the wireless access point, I followed instructions found here: https://learn.adafruit.com/setting-up-a-raspberry-pi-as-a-wifi-access-point?view=all

Now that my Pi was set up properly, all I needed to have plugged into it was power, and a speaker for the ring noise. I used a rechargeable speaker called a Music Bullet I got for Christmas a few years ago, but never really used til now. I also used a Lenovo Battery pack for recharging devices like cellphones and tablets on the go. I tested it, and the battery pack can keep the Pi powered and running for the better part of a day on a single charge. The only thing left to do was copy the sound file to it.

Pi Project finished

Bottom: Lenovo Battery, Middle: Raspberry Pi in a case, Top: Music Bullet rechargeable speaker.

IMAG0008

All that needed to be plugged in was Power on the left, and speaker audio cable on right. The wireless adapter is inside the side door of the case, and protected from being removed.

Screenshot from 2015-03-22 11:10:02

I connected my Laptop to the wireless access point of the Pi, in my case it was called TheCocktailHour as that was the name of the show.

Screenshot from 2015-03-22 11:08:05

Then I used the ssh command to connect to the Pi. Once connected I copied the phone ring .wav file that I found online using the “scp” command. With the sound file on the Pi, It was ready to go.

Screenshot from 2015-03-22 11:08:39

I used a command line media player that was already included with Raspian called “omxplayer” to play the .wav file called Phone1.wav at a volume of 800, which we decided was loud enough for the audience to hear, but not too loud to the point of distorting the ring sound from such a small speaker.

So for the shows, I would plug in the Pi and speaker backstage, and turn everything on. I would have my laptop with me up in the back of the audience, next to the light board. I would connect my laptop to the network “TheCocktailHour, and ssh into the Pi. Once there, it would sit, with the command typed waiting for the cue for the phone ring. When it was time, just pressing enter started the ringing. Once the actor exited stage to answer the phone, I waited a minute, and then used Ctrl+c to end the media playback, as if they answered the phone. It worked flawlessly every night.

If you have any questions, or comments, please feel free to leave them in the comments below, or reach you me at chad.merkert@merkerttech.com


Chad Merkert
Computer Technician/Web Developer
chad.merkert@merkerttech.com
www.merkerttech.com
www.chadmerkert.com

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