Make your Raspberry Pi speak!

I found an article online once that taught me the “say” command on OSX – which i think was pretty cool! The command line function allows you to activate the speech to text feature of OSX and can be used for a variety of fun project. You can try it by firing up terminal (Applications > Utilities > Terminal) in OSX and typing

Say "hello world"

I embarked on an audacious project to teach my son programming over the holiday and thought this feature would be a really cool addition to one of the lessons. The idea is to teach him programming in python on the raspberry pi so he learn basic programming structures and also the hardware that it runs on. Natively the RPI does not have this (say) function built in but lucky I found a way to get it done. Here follows the instructions to get the RPI to speak.

The Raspberry Pi needs mplayer and internet access to make this work. By default it does not have mplayer installed by default.

sudo apt-get update
sudo apt-get install mplayer

Now you can create a command out of it by creating a /usr/bin/say file

#!/bin/bash
mplayer "http://translate.google.com/translate_tts?tl=en&q=$1";

Depending what speaker setup you have, you may need to adjust some settings. In particular, you can try telling the Pi what audio interface to use with the command

amixer cset numid=2

numbid can be any of
0=auto
1=analog
2=HDMI

On a side note, if you get this error from amixer:

amixer: Mixer attach default error: No such file or directory

The fix for this is to run this command

sudo modprobe snd-bcm2835

That command will create the necessary device directories in /dev/snd/

To actually run the file as a command or program it has to be executable, and in linux that means changing the permission attribute on the file:

chmod +x /usr/bin/say

And that’s it, you can now get the RPI to speak by typing the say “hello world” like on OSX.