since your neighbor sleeps until 1pm....
Heavy rubber band... airhorn.....
Rig airhorn to be going off, except have something breakable (strong toothpick or something similar keeping it from going off temporarily)
Attach note to it saying "wake the fvck up the first time they beep their horn"
When horn is beeped, whip airhorn through window... the impact should cause it to get stuck on..
Or, the better solution: call the codes enforcement department of your city... 10 to 1 it's zoned residential and they can't operate a business from there. Let codes enforcement handle it. Depending on the city, it may take several complaints before they actually do something. In my city, it would depend on the neighborhood for how fast they'd act.