I really wish that I would have thought to take more pictures as I was making this thing but of course I didn't think about it until after the fact. Anyway, as they say, necessity is the mother of invention which I suppose applies here. During the summer my friends and I love to do anything outdoors. Floating the river, going to the beach, just generally being outside, and who doesn't like to have tunes when they are outside. Of course there are millions of different radios out there on the market but I just couldn't find anything that fit the bill. Either it was too small and not loud enough, or it was so expensive I wouldn't dare take it on the river or throw it in the sand at the beach. So I set off to build my own. Here is the journey to my first proof of concept.
Step 1: Parts List
HOTGLUE: Seriously, this is probably the most important thing to make sure you have when working on something like this. I soldered, heat shrink tube'ed, and electrical taped everything, and then as an extra measure hot glued those, and everything else just to keep it as water resistant as possible. Also used it to hold things in place, to hold wires in channels in the lid, and even to build little enclosures like you see with the USB adapter. Hot glue is the best. I love you hot glue.
Enclosure: So I started off trying to find the best enclosure. I wanted it to be at least water resistant so I searched for water tight boxes that were big enough but came up empty. Finally settled on a plastic ammo box. I've seen them called Amo can, field box, utility box etc etc. This was one of the few things that I didn't buy online. I got it at a place called gander mountain but I think the sizes are pretty close to the same no matter what brand you get. This is the "medium size. It's about 8" wide which was perfect for the batter that I got(more on that in a moment). It's great to find one that has a smaller compartment on top where you can put controls and not have to open the large lid every time you need to get in there to adjust volume or turn it on/off.
Sound: I found this kit on amazon that worked out perfectly: http://www.amazon.com/gp/product/B003GSLDUO/ref=oh...
It was more than I originally wanted to spend but it worked out perfect and the volume and bass seriously rivals my second gen Bose portable speaker system. It also comes with a waterproof case for your phone, an aux cable, and a nice little volume adjuster. I thought the white speakers were a little too conspicuous so I found some green camo paint in the paint section at the local big box hardware store and sprayed the speaker covers. It ended up being a perfect match. I guess "camo green" is a universal color.
Power: I went back and forth on this one and finally settled on a sealed lead acid battery. Specifically this one http://www.amazon.com/gp/product/B001XV8P0C/ref=oh...
1. For the fact that they are sealed and maintenance free 2. compact 3. capacity 4. cost. I found one that was the same width as my box and it nestles in there perfectly. With the way that the box tapers to the bottom it actually wedges itself in so tight it was tough for me to get back out to try to figure out how to secure in there. The battery life on this thing is just ridiculous. I charge it most of the time just because these batteries need to be as close to full at all times as possible but for a weekend vacation to the beach you wouldn't even need to pack a charger.
Charger: This is the charger that I bought http://www.amazon.com/gp/product/B001G8AIMU/ref=oh...
This is the one thing that I need to improve upon drastically. My temporary solution was to run wire to two bolts that I cleaned up and attach the two leads to the bolts like you would a car battery. Turns out it just worked so i never changed it. It's been about three years now using this thing and never ran into any issues but it's on my radar to improve.
On/Off Switch: RadioShack 12v rocker toggle with LED.
Extras/Optional add-ons: I wanted the box to be practical first, but also have the bells and whistles that we've become accustomed to these days. Things like a battery indicator to know when you need to charge, USB charging for devices that you are using to play music, FM radio if I wanted it, Bluetooth so you don't have to keep opening the box to change songs etc.
Battery Indicator I found here: http://www.aliexpress.com/store/product/Wholesale-...
For USB charging I took apart a cigarette lighter adapter and simply soldered the wires from the on/off switch so it would power it on when I flipped it on. This is where I got the inspiration: http://www.subaruforester.org/vbulletin/f77/diy-ca...
For bluetooth you can really find any rechargable Bluetooth receiver such as this one http://www.amazon.com/iHome-Portable-Rechargeable-...
I just happened to have a dewalt adapter that I use as seen in the picture. You can of course just skip this and use the AUX cable that comes with the speaker amp combo.
For FM radio I had an old Zen stone MP3 player laying around that I just keep in the box if I ever want to turn on the baseball game (GO BRAVES!) or if you just don't want to bother having someone's phone tied up. You can find any small player with FM capabilities if this is something you want to go about.
Step 2: Putting It All Together
Once you have all the parts you need the rest isn't hard, just tedious. Of course start by mocking everything up.
I cut the holes in the side with a dremel using the speaker "gaskets" as a template. Always go small and use a utility knife to trim until they fit snugly. If you are going for the water "resistant" end result as I was, you'll want to make sure the speaker rests nicely up against the speaker gaskets. One thing to remember here is you may have to offset the speakers away from the battery so they won't hit the batter once they go in. Try to think of where everything on the inside will be before you cut, you can't uncut.
Once you've done this you can start to mock up where you want to place everything. Again, be sure to get an idea of how far down things will be poking through and make sure there isn't anything under that it will hit once the top is closed. Don't just go cutting holes willy nilly.
Even though it would have been much better on the other side, I chose to put the amp just above the battery. Only because it would require less mess of wires stretching all the way across the box, I tried to keep it as close to everything as possible, and you can still see I have a bit of a rats nest I could clean up.
Mounting the amp was the only thing that required me to drill through the box. I used Teflon tape to try to get a nice tight seal on the screws and used a nut on the other side to mount the amp against the side of the enclosure. I know this thing can't be completely submerged, but my intention was to not be worried if it gets splashed, rained on, dripped on by the pool etc. So far so good.
I wont go through the whole process of wiring this thing up. If you have any automotive wiring experience at all you'll know what to do here. You are basically installing an amp in a car, just without the head unit since this amp is made to be used without one. The only thing that I wasn't sure of was what to do with the "remote" wire. Just combine that with the power wire and wire them both to the positive pole of the battery. I ran everything through the on\off switch so everything powers up when you flip the switch.
Again, I've been using this for almost 3 years and it's been working flawlessly. kids have played with the switch, it's been sitting in a raft on the river with a couple inches of water in it, it's even fallen down a flight of stairs. The volume has been MORE than sufficient for any situation I've been in, I've just been super happy with the outcome. If there was anything I forgot to cover, or if you have any questions just hit me up. firstname.lastname@example.org