Some music after the range

A few months ago I came accross a shop that was producing portable MP3 player in the form of wooden boxes and 50 cal ammo cases. I was keen on the idea and started searching for all the pieces so I could build one of my own.

Items needed:

• 50 cal ammo case
• Motorcycle amplifier 12V
• 5mm MDF plates
• Velcro
• Lead battery 12V, 11Ah
• 2ea 10cm 2 way speakers
• 2ea 12cm fan protectors
• Black spray paint
• Woofer tube
• Power switch
• Screws and washers
• Nuts and bolts
• Tech 7 glue
• DIY battery monitor
• Tri colour LED
• Audio cable
• Sanding paper

I started out cutting the speaker and speaker mounting holes on the side of the ammo case. Not forgetting the smaller woofer hole in between. On the side I drilled a hole to install the power switch. When drilling make sure the switch will be positioned so that you can manipulate it from the hole in the side open/closing lever of the ammo case. Then I trimmed the MDF plate so it would fit nicely inside the case. The back plate was trimmed to the full interior length of the case. The previous cut out holes were transferred on the front MDF plate and cut out. Using Tech 7 I glued the MDF plates into place with the exception of the back plate. This should be able to slide out if necessary because I was planning to mount all electronics and battery on it.

In order to check the battery status I looked for a circuit that showed the status through a tri colour led. Green above 11,5V, Orange between 11,5V - 10,8V and red below 10,8V. These values can be changed with the potmeters.
http://kd1jv.qrpradio.com/batmon/batmon.HTM

I made the circuit on a experimental board and drilled a 5mm hole in the woofer tube. From the outside the battery status was visible through the bass tube.
The two fan protectors were sanded and sprayed black. After drying I cured the paint by baking the protectors in the oven for about 20 min at 200°. Try to do this without the misses at home because it tends to smell.

After mounting the speakers, protectors and switch it was time to install all electronics on the back plate. On the left I installed the amplifier with screws and in the middle the battery. The battery is held in place by a self made Velcro harness so changing it isn't a big issue. Mount the battery with the connections to the top so that recharging is easy. On the right I mounted the battery monitor. With this setup the ammo box will also be in balance. The battery alone weighs a couple of kg.

Last but not least I wired everything up and added an Ipod for testing. Closed up the case and the sound was just great.

A nice gadget when maintaining your weapons ;-)