The RaspiVoice Kickstarter project is an incentive to give Arduino users the opportunity to leverage the superb sound playback capabilities of Raspberry Pi into any Arduino project. It achieves this by allowing Arduino users to use a low cost Raspberry Pi as a serial text to speech device. Basically almost anything that you can output on the serial port of the Arduino using Serial.Println statement are received by the Raspberry Pi unit and converted into speech.

Step 1: How It Works

There is a special small interface board (or shield) that plugs into the Raspberry Pi that adapts the 5V signal of the Arduino TTL output to the 3V3 input required by the Raspberry Pi. All that is required is to connect three wires (Rx, Tx and GND) between the Arduino and the Raspberry and you're in business.

The Raspberry Pi solution is a pre-compiled project called RaspiVoice and a lot of effort has been put into making it as simple as pie (excuse the pun) for non Raspberry users to set up and use. Raspivoice can produce three different types of sound:

High quality male and female voice. The high quality male and female voices are produced by playing separate voice WAV files of each of the individual words that forms a sentence. The result is that the words are clear and sounding like a real human, but the individual words are still broken up. The type of text to speech is good for short sentences where clear voice quality is important, but it does not sound right for long sentences. The RaspiVoice app includes about 9000 male and female voice files on SD card to facilitate this type of speech.

Medium quality speech synthesized speech voice. This voice type is based on the eSpeak text to voice synthesizer. Yes, it sounds a bit robotic and can easily be confused with Stephen Hawking, but is speaks fast and can say almost anything under the sun. It even allows you to have speech in different nationality accents and languages. The method of speech is preferred if you have to produce lots of speech or you want it to speak fast. But if you are not listening carefully, it can sometimes be hard to follow.

WAV file playback. The RaspiVoice device also allow you to add your own WAV files on the SD card of the Raspberry Pi and instruct it to play them back through serial port control. This useful for for things like sound effects or music clips etc.

Want to hear a demo what it sounds like? There are some demo videos and sound files available. Please check out the project website at www.raspivoice.com or follow it on https://www.kickstarter.com/projects/raspivoice