Lesson Four: Play Lists
Now we are going to have our alarm clock play music. Once we have our amplifier and speakers wired up, it is time to create a list of audio files for our alarm clock to play.
First, let's take a look at our "Upload Audio" page by clicking on the top navigation bar. Once the page appears we should be able to see a list of files that are already loaded on our Hack Clock, and also a button to upload our own files. Right now we are going to use the two files that came with the Hack Clock - AmicusMeus.ogg and TestTrack.ogg.
Let's return back to our "Edit Code" page by clicking it in the top navigation bar. Let's create a new function, this time to play music:
from hackclock.runapp.Libs.GStreamer import Speaker # Connect to the speaker speaker = Speaker() # Play some music def playMusic(): speaker.playList()
We want to tell the speaker what audio files play. We don't want to have just one file either - we want to provide an entire play list. Python can create lists of elements by containing each item in  brackets, then separating each element with a comma. For example:
# Play some music def playMusic(): speaker.playList(["TestTrack.ogg", "AmicusMeus.ogg"])
The change in the code above will create a list with the names of two tracks, TestTrack and AmicusMeus. This list then is sent to the speaker's function playList, which will play each track in order.
Next, let's tell our Hack Clock to start this playlist at 9:30 in the morning so we can wake up to our lovely music. Here we can inform the clock that we want our playMusic function to be called at a specific time:
# Wake us up at 8:30 in the morning clock.atTime(8, 30, playMusic)
Excellent! Now at 8:30 in the morning our clock will begin blasting some music. Change the time to just a minute in the future - see if it will begin playing!
Now we need to learn how to add some new hardware to our clock: let's have our clock tell us the temperature outside when we press a button.