Audio & Voice Announcements

The objective of this project is to look at audio announcements as part of our Home Control System (HCS), the goal being to provide a simple and efficient user experience for certain information. These announcements could be in the form of audio tones, pre-recorded speech, pre-recorded text-to-speech (TTS) and dynamically generated text-to-speech.

The objectives of this project are to:

• Experiment with what type of audio works best and to determine where audio announcements are appropriate.
• To understand what hardware is required to best generate audio and where it is best located.

Progress

Audio Tones

We have collected a range of audio tones and are currently testing them to see which work and under what situations.

Text-To-Speech

The advantage of TTS is that you can use it to provide a consistent set of audio voice announcements in terms of volume, speaker and quality. There are some very good (and also free) services to generate the required announcements. These are a few web-based services we have looked at and like:

• iSpeech - Female american voice.
• IM Translator TTS - Range of voices.
• TTS - Applications that you need to download.

The disadvantage with web-based services is that you need a PC to generate them and another to record them. Ideally, both should be laptops, to avoid any mains hum on the recordings. None of the above services generate an audio file directly.

In the end, we decided to use an iPhone app to generate the text-to-speech for us as we found one that had a range of good quality voices. The app is called Speak It!. We are using the 'Lucy, British Female Voice'.

Recording & Editing Audio Files

To do the audio recordings and editing we are using Audacity software which is open-source. It allows you to tweek the levels and avoid clipping of the audio. It also allows you to crop the audio files and save them in a wide range of formats.

Java Audio Playback

Rather than write a load of code to play audio files in our existing Java code, we did a quick search and found this example, which explains how to simply achieve our objectives. It took less than five minutes to get this integrated and working.

Audio Hardware

Our Home Control System (HCS) is based around a Mini-ITX PC which has stereo, line-level audio output. For now we have used some powered speakers to play out audio into our study and these are using a 12Vdc power supply.

The intention is to install some ceiling or in-wall speakers near the front door and back door, to see how well this works and to test out possible hardware solutions. We've never been particularly impressed by ceiling mounted speakers and they don't look very good. They do have the advantage of being relatively cheap though. Ideally, we would like to install some hidden 'in-wall' speakers like these ones Amina Technologies but they are quite expensive. They are certainly something we will investigate for our next home.

The other option is something like these Monitor Audio SoundFrame speakers which are not invisible but, are decorative and mounted into the wall, rather than within it.

Experiments

Having got the basic audio capability working, the next part of this project was to see where audio announcements are appropriate. By 'appropriate' we mean that they are not intrusive, add real value and are the best mechanism to convey the piece of information.

Mains Power

An obvious application for voice announcements that we spotted was to convey when the mains power had failed (.WAV file) and when it had been restored again (.WAV file). Whilst this is quite obvious during the evening or night time, it is not during the day. It was very simple to add this as an initial test case.

Twilight

A second case was the announcement of dusk being detected. We could annouce dawn as well but we don't want to be woken up at around 4:30am during the summer months! Dusk is signalled in our house by variosu lights comming on automatically but this only happens in a few rooms.

House Alarm

It makes sense to announce when the house alarm is enabled or disabled. It also adds value in playing out a reminder when the front door is opened, thus triggering the alarm and reminding the person entering that they have x seconds to deactivate it before the external sounder is activated.

Conclusions

Our current thinking is that audio and voice announcements have limited value in an automated home but, there are a few instances where they prove useful.