The inspiration for this project came from spending a lot of time out in cold environments, where even the thickest thermal layers just aren't warm enough. The heated vest was built with the intention of staying warm on the ski slopes as well as when on the water in the midst of a long sail. It is fairly easy to assemble, and requires only a minor understanding of simple electronics and the ability to solder.
Step 1: Locate Materials
For this project you will need:
a battery pack containing positive and negative ends along with 4 AA batteries
4 washers (any size will work, though I uses 16mm)
2 sets of nuts and bolts
a soldering iron along with solder
10 ft of heating wire
1 ft of thin spare wire
an old t-shirt
hot glue gun
Step 2: Extend Battery Pack
For this vest to make sense logistically, the battery pack which powers the heating wire cannot just hang loose from the shirt, for then there is the major possibility that a battery falls out and the connection is lost. So, I soldered an extra six inches of wire onto each the positive and negative ends. This allows the pack to lay comfortably and compactly in any pant or jacket pocked. Once completed, you may want to run some electrical tape over the wire for safety's sake as well as giving the product more appeal cosmetically.
Step 3: Establish Ends of Battery Pack
To allow for the flow of electricity, remove about an inch of the wire cover. Then, attach washers to the ends of each stripped wire, fold the wire back onto itself, and tape the ends.
Step 4: Cut Length of Wire
Once you have your power source all taken care of, you are now ready to cut a length of heating wire. Due to lack of resources, I used copper wire, though ideally, a length of nichrome will suit you best. Cut about ten feet, enough to cover the front and back of the vest.
Step 5: Establish Ends of Wire
Now, if your wire is covered, you will need to remove this outer layer with wire cutters. Remove about an inch, but do so in segments; attempting to remove a full inch of cover in one cut will most likely cut the core of the wire. After, bend the wire around a washer, then tape the end of the wire back to itself. This will allow the transfer of electricity from the battery pack to the shirt.