I turned a military ammunition box into a power supply, with 5, 9, 12 and 24 Volts. The displays on the front are for the current draw.
Step 1 – buying a suitable ammo box
There are a few sizes of ammo box available off eBay. I based the size of this one on the type of block PSU I was going to use.
Step 2 – check all the components are going to fit
I find calculations on paper are really hard to get right, nothing really beats buying everything you need and physically testing how it will all fit together.
Working out the position of the current sensors.
The block power supply took up a large portion of the inside. Also important to note you need space to fit your hands to screw and glue all the wires inside.
Step 3 – measuring out where to make the cuts and drill the holes
Once I am happy that everything will fit in the ammo box, I can measure out the plates and cuts I will need to make.
The back of the power supply.
The aluminium plate that holds the DC-DC converters.
Step 4 – design the circuit
The circuit is really simple, the 24V Power Supply is divided up between all the DC-DC converters, which in turn then go through the Ammeters.
Step 5 – make the layout on eMachineShop
Using free software from eMachineShop I could create the layout to then print onto paper and lay onto of the ammo box.
When making manual cuts I found it very important to use printed cut outs, rather than make measurements with a ruler and pen.
Step 6 – using a rotary tool to make the cutouts
Using a rotary tool to make the cuts into the ammo box.
Step 7 – tidy up the cuts with files
Using masking tape to create the straight line that I can then file to.
The bezel of the current monitors saves me here, it was really hard to create a straight line, so all of the imperfections are recovered from here.
an easy mistake to make
Watching out for the chuck on the rotary tool is very important. Many times I have marked my projects by concentrating on the cutting wheel and not where the chuck of the rotary tool is,
Step 8 – testing the power supplies
Testing of the DC-DC converters is really straight forward – plug them in and check the output. A mistake I did make was to put the current monitors on the positive line – it shorts. So moved those onto the return line.
The finished article