MusicPD Soft Ramping Alarm Clock

For a long while, I’ve had a disdain for the abrubt awakening caused by traditional alarm clocks. I wanted something that was still going to wake me, but wouldn’t cause my heart to be racing first thing in the morning. So I wrote some crontab entries to help:

0	5	*	*	*	mpc vol 10
0	5	*	*	*	mpc play
5	5	*	*	*	mpc vol 20
5	5	*	*	*	mpc play
10	5	*	*	*	mpc vol 30
10	5	*	*	*	mpc play
15	5	*	*	*	mpc vol 40
15	5	*	*	*	mpc play
20	5	*	*	*	mpc vol 50
20	5	*	*	*	mpc play
25	5	*	*	*	mpc vol 60
25	5	*	*	*	mpc play
30	5	*	*	*	mpc vol 70
30	5	*	*	*	mpc play
35	5	*	*	*	mpc vol 80
35	5	*	*	*	mpc play
40	5	*	*	*	mpc vol 90
40	5	*	*	*	mpc play

For those not used to reading crontabs, at 0500 set the volume to 10%, then start playing music, and every five minutes increase the volume by 10%, play the music again (as it might have been turned off), and continue to the normal listening volume (90% in this case).

Of course, writing that by hand is a pain, so I have an xs script generate that chunk of my crontab for me:

# User configurable values
max_vol	= 90
min_vol	= 0
hour	= 5
min_step	= 5

#####

# State variables
vol	= $min_vol
min	= 0

while {$vol :lt $max_vol} {
    # Increment volume
    vol	= `($vol + 10)
    cron	= $min $hour \* \* \*

    # %flatten takes a string and a list, it joins the list with the string
    echo <={ %flatten \t $cron 'mpc vol '^$vol }
    echo <={ %flatten \t $cron 'mpc play' }

    # Increment minutes
    min = `($min + $min_step)
}