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I originally came across this idea from a website called http://macgyverisms.wonderhowto.com which in turn was linked to dustinbikes instructable for Ammo Box Speakers https://www.instructables.com/id/Ammo-Box-Speakers-1/. After doing a little research I decided to make my unit portable with a SLA (sealed lead acid) battery. I was able to put together my parts list and placed an order from Amazon. I did make a trip to my local Good Will to pick up a working 12v cigarette USB charger, and I happen to work with computers so I had access to plenty of old power supplies. I had all of the tools that I found necessary to put my build together.

Step 1: Parts List and Tools

PARTS LIST
.50 cal Ammo Can
AMP ( Lepai LP-2020A+)
Set 4" car speakers (Kicker DS40)
12 volt Sealed Lead Acid Battery (UB1280)
12 volt switch (Amico Angel Eye White Led Light 16mm 12V Latching)
6 position dual row terminal block (Used to keep wires organized)
Old PC power supply (wire and connectors)
One 3.5mm male to female cable
Shrink tube
Velcro
Wire connectors
12v cigarette USB charger
Screws/Nuts (#8-32 x ¾ Flat Head Phillips)
Sugru
12v battery charger

TOOLS LIST
Safety Glasses
Tape measure
Speed square
Compass
Jigsaw
Drill
Drill bits
Wire stripping pliers
Wire crimping pliers
Glue (PL375)
Card stock
Scissors
Multimeter
Metal File
Soldering Iron
Lighter for shrink tube

Step 2: Switching Wiring



One mistake I made that you can avoid, when selecting your switch make sure to choose a latching switch and not a momentary switch. If you order a momentary switch like I did the first time, your boombox will only fire up as long as you are holding the button down.

I wired and tested everything outside of the box. I elected to use some of the 4 pin Molex connectors from an old power supply, this is a quick easy disconnect that I know I can rely on. I just pulled the unused pins out of the plastic connector with pliers. I also used wires from the power supply rather than buying wire.

Wiring the Switch

***Disclaimer, I don't claim to have anything more than very basic electrical wiring knowledge and am not an electronics expert in any way, shape or form***

I used a 5 pin LED switch.

From left to right:
LED NEG | C1 (common) | NO1 (normally open) | NC1 (normally closed) | LED POS

Negative connection into switch (from battery) to LED NEG

Negative connection out of switch (to 6 post terminal block)
LED NEG to NEG of Molex attached to terminal block

Positive connection into switch (from battery) to NO1

C1 jumped to LED POS (this will turn on the switch LED when the switch is in the ON position)

Positive connection out of switch (to 6 post terminal block)
C1 to POS of Molex attached to terminal block

I ran wire to jump the POS and NEG connections to the other blocks in the terminal block. I used a terminal block to make things nice and neat, this is just my preference and is not necessarily needed. I checked the voltage at the battery and then at each one of the terminal blocks where I jumped it.

Step 3: USB Charging

Wiring up USB charging
The next step in the wiring was to repurpose the 12v USB charger. The reason I chose to use one of these was there is already a 12v to 5v converter made for you. I paid 1$ for a working charger. I opened it up and clipped the NEG wire connections and soldered them together. Next I soldered a longer POS wire. I put everything back together in the case, hooked to the terminal block and tested the output.

Step 4: Wiring the AMP

Wiring the amp
I saw some guys that soldered connections directly into the amp, as I said before I am not an electronics expert so I opted to snip the plug off the power cable and connect it to my terminal block. Since the cable was not marked POS and NEG here is how I tested. I hooked only one wire at a time to a NEG connection on the terminal block. I was able to determine the outside of my plug was negative by the wiring diagram on the amp above the plug. I held the black connection on my multi meter on the outside of the power connector and the red connection on a positive block on the terminal. If I get a reading on my meter, the wire hooked up is NEG and completes the circuit. If I don't get a reading on my meter, the wire hooked up is POS and did not complete the circuit. After determining and marking POS and NEG power supply wires, I hooked them to the terminal block. I tested once again to make sure I have a completed circuit before plugging into my amp.

Step 5: Final Wire Testing

Final Wiring testing
So now with all the wiring hooked up outside of my box I hooked up the speakers and a 3.5mm cable to the amp and tested to make sure everything is in working order before cutting on my ammo can.

Step 6: General Layout

General Layout and Cutting Speaker Holes
I decided on a general layout to make sure everything fit nice before making any cuts on my ammo can. I measured everything out and made a template with a piece of card stock using a tape measure and compass. After cutting out the template, I dry fitted the speakers to make sure the holes were the correct  size...always measure twice and cut once, they don't give away ammo cans. Use the template to transfer the pattern to the ammo can. Use a drill bit to drill into the inside of each speaker hole to get the jigsaw bit in to cut out the speaker holes. After getting the holes cut out, I ran a file over the edges to take off any sharp edges.

After getting all of the metal file shavings out of the box and off my work bench (don't want the shavings sticking to the speakers) I dry fitted the speakers. After making sure they fit correctly, I marked and drilled holes for the screws to hold the speakers in place. At this point I also drilled holes to the correct size for my switch and 3.5mm aux input. Once again, make sure to clean out metal file shavings before putting the speakers back in the box.

Step 7: Putting It All Together

Putting everything together
I used Sugru to hold the mounting screws in place for the amp. I didn't want to drill any more holes in my ammo can than I had to. I also marked and glued the terminal block in place. I let everything set for 36 hours to ensure it was dry. I took apart an old 3.5mm jack and installed it in the box. I cut and soldered all the necessary power cables to length. I used the self-adhesive Velcro to hold the battery in place.

Step 8: Some Thoughts



I have only had this build put together for a few weeks now. I have not fully discharged the battery so I am not sure how long my setup will last. From what I have read, it sounds like it should last 8-12 hours on a single charge. I have also added USB charging capabilities so this could dramatically cut down on runtime if you are charging you music device.

I plan on using my boombox mainly for camping and fishing. It is a bit heavy, so I wouldn't plan on strapping it to your backpack!

One thing I plan to add in the future is a Bluetooth receiver so you don't need to plug your phone directly to the box. I haven't found a good hack for the Bluetooth yet, I may need to purchase a receiver.
Why do you need a molex connector?
I made it great Instructable
Question, i am getting little to no audio out of my speakers even with both tbe amp and phone volume maxed out. Any ideas. Im pretty electronically inept so any and all suggestions are great.
How do you charge the system?
mine is setup so that the 12v lighter plug also accepts a charger. 12v trickle charger for car batteries 12v 1a
<p>how could you do the lighter charger for this one?</p>
i just got a cheap 12v battery charger and connected a standard male lighter plug onto it. then the radio has the female connector.
battery is dead in this picture thats why it has a low voltage
<p>Unplug the battery and hook a cheap universal charger.</p><p>I also go tired of pulling my multimeter out to check the charge so I added a meter to my box. I used the momentary switch I mistakenly ordered for my original power switch and ordered a cheap multimeter. It is hooked to the terminal block behind the power switch so the power to the radio has to be on for the meter to work. I also had to use a smaller battery so I could get the multimeter to fit into the box.</p><p>Since it was taken apart to cut more holes in it, I decided to paint it matte black also.</p>
<p>how do you charge it?</p>
What is the Shrink tube for, and where can I get old PC power supply
<p>Hey guys,</p><p> Great build ! I am working on my second variation on this theme by using a jerry can, my original is an old Singer sewing machine wooden case.</p><p>This time round as the can has no lid and will effectively be sealed i want a way to charge the battery externally ? I am thinking use a 3 way toggle switch with an 'on amp power', 'all off' and 'on just battery circuit' but could do with some help and suggestions as to how to wire it and a good way to connect the battery externally to the charger ?</p><p>Cheers all for your inspiration ;0)</p>
great job! i like the wiring and I will be redoing mine because I'm jealous. i made this 2 years ago and it has worked beautifully. the wiring is horrible I know. its very loud but I noticed that it was a lot clear and had better bass when the lid was open so I installed a bass tube beneath the latch so it wasn't as noticeable I welded the handle in the up position to stop the rattling also not shown is the 12v battery because i neglected it and now i need another and I have a small battery powered Bluetooth transmitter I can use instead of a wired connection to my phone surprisingly enough it worked even being inside a steel container though range is about 6 ft... great job on you're instructable
<p>Nice job! I made a slight variation as I had a 12v 4800mAh Li-Ion battery from a CCTV system. I used a dual throw toggle switch to select from battery or AC power. I also lined the can with some Duramat scraps left over from a car install and it made quite a difference. Also, due to the type of drivers I used (3.5&quot; BMR speakers), I installed a 1.5&quot; x 4.5&quot; port. Finally, since the amp has both RCA's and 3.5mm mini-jack inputs, I installed both on the side of the can. As for the Bluetooth connection, I'm using the board sold by Parts Express for around $18. It works great and comes pre-wired with a USB connection that I hooked up to a separate LiPo battery I had left over from a RC helicopter and paired it to USB charge port. Eventually, I'm going to wire a resistor to step down the 12v to the 5v but will need to install a ground loop isolator as the switching power supply for AC use generated a nasty bit of hum. </p>
How do you charge it?
<p>I have little to none experience in this sort of things, but I really want to build one of these. Could you recommend some brands for like, pretty much all of the ones you used? Thanks</p>
<p>Anything I did not have was ordered from Amazon. The part numbers I used are listed in the Parts List.</p>
<p>buy cheap bluetooth headphones and hack them. Look for the bluetooth cassette hack on here.</p>
<p>I have built a version of this myself and searched high and low for a 12v Bluetooth receiver and finally found one made by Fusion who make them for boats. It works great.</p><p><a href="http://www.amazon.com/Fusion-MS-BT100-Bluetooth-Dongle-Marine/dp/B00CUMQU50/ref=sr_1_1?ie=UTF8&qid=1424491340&sr=8-1&keywords=fusion+bluetooth" rel="nofollow">http://www.amazon.com/Fusion-MS-BT100-Bluetooth-Dongle-Marine/dp/B00CUMQU50/ref=sr_1_1?ie=UTF8&amp;qid=1424491340&amp;sr=8-1&amp;keywords=fusion+bluetooth</a></p>
here is my take on the instructable. thanks for the inspiration!
this is such a good project i am making one myself.
<p>How did you connect it so that you could charge the battery without taking it out if the box? thanks?</p>
<p>Great explanation of the switch! Just got one in the mail today and your description saved me a lot of time=)</p>
<p>The box should really be lined with some kind of padding. Otherwise internal reflections will make it sound bad. You might also consider making an enclosure out of MDF to fit inside the box like a box inside of a box. That will reduce flexing and improve bass response.</p>
<p>If the box is lined with fluff, sound resonance will decrease. Without the resonance, the speakers will make very little sound. The build up of the internal reflections and the appropriate release are what make the difference between an average setup and a fancy one.</p>
<p><a href="http://www.tnt-audio.com/clinica/speaker_design_pt3_getstuffed_e.html" rel="nofollow">http://www.tnt-audio.com/clinica/speaker_design_pt3_getstuffed_e.html</a></p>
<p>This is a statement made on 2004-11-23 by Rick Andersen:</p><p>breadboard&quot; your circuits and connect a 2&quot; or 3&quot; <br>speaker, bare and open, just sitting by itself on the breadboard, you're <br> going to conclude that there's not enough volume, and think you need <br>watts instead of milliwatts.... listen to me; I've had years of <br>experience with this: Mount your little speaker in a cardboard or wooden <br> box, or even a decent plastic one (or even in a styrofoam coffee cup!), <br> and you'll immediately hear a tremendous difference in both volume and <br>sound quality-- it never fails to surprise first-time builders when they <br> experience this for themselves. Acoustic resonance via a speaker box <br>really does boost the sound and takes some of the &quot;tinniness&quot; away, <br>letting you get away with using cheap transistors for the output stage. <br></p><p>So you can pick which site you pull your theory from. I like how Yoyo Ma doesn't stuff fluff into his cello. Maybe other musicians pack their stradavarius with foam. Personal choice.</p>
<p>Indeed, Mr. Andersen is quite correct, but a quote about the complete absence of an enclosure does not make sense. If you put a speaker in a can, it is going to sound like it's in a can.</p><p><iframe allowfullscreen="" frameborder="0" height="315" src="//www.youtube.com/embed/uVn0yaRr3T0" width="420"></iframe></p>
<p>OK, so let's be honest with ourselves here and treat this for what it is...a cheap, rugged ghetto blaster. What it is not...part of your HD basement theatre system. I took an old metal ammo can and made a portable speaker system out of it. For what it is and the 75$ I spent I have to say it sounds fantastic. I don't see any reason to dump any more money into this project. It works great for the intended purpose, a somewhat indestructible way to take my tunes anywhere with me...specifically camping and fishing. You can only polish a turd so much, but I have to say this one has a nice shine to it and my polishing is done.</p>
<p>LIKE IT &amp; HAVE LOTS OF AMMO CANS , TO MAKE THAT WORK. THANKS VLAD.</p>
dx.com has bluetooth 3.0 recievers for $13 USD. They have USB too.
ive built them befor when I was in the military. I love them and still use them... the only thing id add is so sound dampening material like duramat that I bought at cartoys. makes the sound 100% better and worth the price
<p>how much did all this end up costing</p>
<p>I spend 75$ but I had the battery and some of the other little parts already.</p>
Bluetooth audio receivers can be found on the cheap. Check partsexpress.com, I know they have one that is not very expensive at all.

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