Control Hubs: Bringing It All Together - Smart Home Automation with Linux and Raspberry Pi - page 240

following day. The last point, amusingly, requires additional logic because, if I'm home after midnight, then the
“following day” is actually the same day, and we need to amend the process accordingly:

# For early morning/late nights
if [ `date +"%H"` -le 4 ]; then
REQUEST_DAY=today
MESSAGE="Back late - I hope it was a good night. Let's talk about the morning"
else
REQUEST_DAY=tomorrow
MESSAGE="Let us talk about tomorrow"
fi

CONDUIT=vox
$MINBIN/report $CONDUIT shower echo $MESSAGE

# ... other messages here ...

$MINBIN/report $CONDUIT shower echo Let me look at the calendar
$MINBIN/report $CONDUIT shower calendar $REQUEST_DAY
$MINBIN/report $CONDUIT shower echo Checking house events
$MINBIN/report $CONDUIT shower lstatus $REQUEST_DAY
$MINBIN/report $CONDUIT shower weather $REQUEST_DAY

Minty
Minty serves two purposes. First, it is a timeout system in which devices will auto-turn off if they are not used within
three minutes of their last usage. Second, it is a reference counting utility, to ensure the first component acts intelligently.
Therefore, if two people switch the light on, then it switches off three minutes after the last person to switch it off. This is
essential in an automated house as it's possible for one person to switch it on locally, another to do so remotely, and the
computer to do it automatically . . . and for all three to expect the device to be on while they're interacting with it.
To facilitate this, each device has a Minty on event, and a corresponding off event, described in two scripts such as:

/usr/local/minerva/conf/minty/shower_speaker/on
/usr/local/minerva/conf/minty/shower_speaker/off

So, when the device is first required to switch on, the script minty start shower_speaker is called, and the
time is noted. If this is the first time that the shower speaker is being turned on, then the script above is run. If not, its
count is incremented. Once you've finished using the device, and turn it off (with the predictably named minty end
shower_speaker ) the count is decremented and, if the count reaches zero, the three-minute timeout begins.
Because the on script is only called on the first invocation, you can trigger the same event from lots of different
places. So, for example, the shower speaker remains on if:

u you're playing music in the shower

u listening to the computer voice reading your calendar

u
Each of these event triggers make an identical to call to minty start shower_speaker so only after you have
stopped listening to music in the shower, and you're having your schedule read to you, and you've switched the light
off, does it get ready to switch it off.
Of course, if you return to the shower within three minutes and play more music, then the three-minute time out
begins again.

the shower light is on