On a scale of 1 to 3, this project ranks a 2 in difficulty. You'll need to be able to solder, desolder, identify a few components and adapt this design to suit your application.
My out of pocket costs were $6. The plastic, speaker, zip ties, misc. wire were either found or leftovers from other projects.
~1 hour once you have all supplies
From an appearance stand point - I give it a 9 out of 10
From a functionality stand point - I give it an 8 out of 10
From an audio stand point - I give it a 6 out of 10
From a loudness stand point - I give it a 7 out of 10
(A prior version of this would have had scores under 5)
As a side note - yes, this is technically not a stereo. Complaining about that is your prerogative, but I couldn't care less. If I say sharpie, you know it's a permanent marker - communication has been served.
Step 1: Materials
1 Power Supply
*$5 Harbor Fright Megaphone
*Free speaker from discarded boombox
*Batteries, AA's are fine - they need to put out ~6V (I later used a 6V gel cell) - you can also use the original battery pack if that suits you
*Wire, some wire came from boombox - I also used a Cat5 cable
*Headphone jack can come from a pair of headphones
- For the mount, I used a piece of plastic that I then laser cut to fit perfectly into my bike rack - feel free to improvise, similar quality can be had using thin plywood and a jigsaw ;)