After viewing hand warmer my friend challenged me to make something that can keep his feet warm in snow and in daily use too
Thus i am proud to present "DIY HEATED INSOLES"
These insoles are very easy to make and a special focus is kept on their performance and the ease of getting the materials required
In order to have a detailed look at the project watch this YouTube video
FULL VIDEO TUTORIAL
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Step 1: Grab Them All...
li ion 18650 batteries
insole of your size and an insole of smaller size
30swg copper wire 10m
hot glue gun
wire cutter and stripper
paper hole puncher
Step 2: Make a Template
Using the smaller insole draw and cut out a template
smaller insole is used in order to get a perfect fit in the shoe
also heating is proper as thier is no contactless point on the insole
Step 3: Using Puncher Make Holes
By making holes all around the insole we make sure that our heating element(copper wire windings) will stay in place even with the foot movement .
then measure a copper wire of 30swg in 10metre length and cut into half of 5m pieces for each shoe.
the resistance of copper wire will be 6.4ohm of the 10m wire that will be unvieled and tested later
Step 4: Wind in the Described Fashion
wind the copper wire according to your feet pressure points
no. of windings
Step 5: Protect the Heating Element
the copper wires are now exposed and thus may get stuck in your feet and get destroyed.thus cut out two pieces of thick paper and glue it onto the heating insole
Step 6: CONNECTING THE HEATING ELEMENT
Using a lighter burn out the insulation of the copper wire and then rub off all the insulation by a fine grit sand paper.
After removal of the insulation just wrap the copper wire end around the wire and solder it.
Now using a heat shrink tubing make your connections short-circuit proof.
Step 7: BATTERY PACK
Solder the two lithium-ion 18650 cells in parallel.
We need an increased capacity as it runs at a longer duration of time.
make sure that you don't get your soldering iron for too long in contact with the batteries.
Step 8: Electronics Time
Solder all the electronics components as shown in the circuit diagram.
The diode is the major component here that provides us a voltage drop of 0.8v as when connected across a 5v usb jack it would lead to a voltage of 4.2 across the li ion cell which is the safe charging voltage for it.
Step 9: Tape Up Everything
Preferably use electrical tape in order to get a nice and tight fit of all the electronic components onto the battery pack.
Step 10: ADDING THE CONNECTORS
Solder the male and female headers.using hot glue gun secure the connection junction and smooth it with a piece of paper.these are the outcomes of what i have learnt from a lot of prototypes
Step 11: TESTING TIME
run-time >4 hrs
the runtime of 4 hrs may seem less but actually 4 hrs meant 4 days for me because after turning on for just 15 minutes my shoes kept warm for 2hrs in snow.
it also includes a auto shutdown feature that you might even never have thought of...
when the copper wire heats up it leads a increase in its resistance due to which the power output decreases and thus decreasing the heat automatically
Step 12: Put It All Together
Put the heating insole below your regular insole.
In between the laces put the battery pack and tighten them it ensures a perfect fit of batteries without compromising the comfort.
Now the test results shows a very favorable shoe temperature.
CONGRATULATIONS YOU MADE IT