If you ever catch a cold elbow, you know that severe pain can last for several days. The pain abates when warm up a sore spot but how to do it in a trip? In the last safari I was sleeping at the open window and can't move a hand when I woke up in the morning. Severe pain prevented even walking and became unbearable at the rest. But the pain subsided when I warmed myself at the fireplace and I decided to make a portable heating wrap for such cases.
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Step 1: Shopping List
1. A piece of elastic fabric (I used a piece of 0.6x2 feet folded two times).
3. Silver glue.
4. An old USB wired connector.
5. A piece of wire.
6. A rubber glue.
7. USB power bank 5 Volt and 2 Ampere at least recommended.
Step 2: Choosing a Heater. a Little Theory.
I used a carbon heater fiber rope. In contrast to the nichrome wire and other types of heating elements, carbon rope doesn't afraid of multiple bend and can work for years.This allowed me to create a universal elastic heated bandage suitable to be worn on your arm or foot and convenient for people of different body type.
Carbon is the most efficient radiator of heat. A significant part of the energy emitted in the infrared range and penetrates deep into 4-5 cm of the human body. This warms the body evenly and retained an intense blood flow for a long time, as after a good massage.
Carbon fiber is breathable, so your elbow does not sweat and you will feel comfortable.
Carbon rope isn't afraid of high temperature and has an unlimited period of work, but electric wire at a high temperature is rapidly oxidized by atmospheric oxygen, electrical contact will broken and got very hot. To make a reliable contact is necessary to isolate it from the oxygen with an adhesive. Since the adhesive certainly get between terminals, it must be electrically conductive adhesive. The best is silver glue.
As you can see, the contact place with a silver adhesive is cold and contact without silver greatly overheated.
Armed with this knowledge we can in just one hour make a quality and reliable heated wrap. See how easy it is.
Step 3: Just Glue It!
I used a regular USB 5V 2A 10000 mAh Power Bank. Carbon rope connected in parallel 2 feet x 3 pcs. It will give a temperature of about 110 degrees Fahrenheit. The current about 1.2 Ampere, and power consumption 6 watts. Working time more than 8 hours!
Wrap wires in the contact points of carbon as shown in the figure. Apply a drop of silver glue on each of the contact.
Connect the thermostat in series with the carbon rope. The thermostat will turn off power when the desired heating temperature. With this option you can connect your heated wrap to a power supply with any voltage from 5 to 12 volts.
Take a piece of elastic fabric measuring approximately 0.6 x 1 ft. The length of the fabric depends on the diameter of your hands / feet. The elasticity of the fabric must allow the stretch on leg and did not fall from arms.
Apply a small amount of rubber adhesive on one side of the carbon rope and glue it onto the fabric zigzags. Zigzag allow the fabric to stretch freely on any arm or leg.
Cover with a piece of cloth the same size and sew them together. Then roll up into a tube and sew edges.
Step 4: Power Up Your Health
All is ready!
Put it on the sore arm or leg and connect to the USB power bank. Carbon rope will heat up your body in just one minute and you get rid of the pain and cure the knee or elbow even in a hike.
Participated in the
Sensors Contest 2017