Summer is hot. Especially if you are being active outdoors. So to avoid getting overheated, I made a simple thermoelectric cooling unit that attaches to your wrist. This is able to rapidly cool your entire body.
You can use this to cool down after a workout or between plays. The unit is small and easily portable. All you need is access to electricity such as a 12 volt battery.
Step 2: How This System Works
This system uses a thermoelectric cooler (or a Peltier cooler). This is a miniature refrigerator that works by uses the Peltier effect. When a circuit is made using two different types of conductors, the junctions where those conductors meet experience a change in temperature. One junction will get hotter and the other junction will get colder. In a thermoelectric cooler, a large number of these junctions are connected together. They are arranged so that all the cold junctions are on one side and all the hot junctions are on the other side. These units can act as coolers or heaters depending on which direction the electrical current is moving. In this application we are attaching the cold side to a person's wrist in an attempt to help cool the body.
This cooler is attached to the person's wrist right next to the radial artery. At this point there is a large amount of blood flowing near the surface. By cooling this area, the body's circulatory system helps to distribute the cooling effect throughout the entire body.
Step 3: Materials
Here are the materials that you will need for this project.
Cooling Unit Materials:
1/16" thick aluminum plate
Machine screws for the heat sink
Small 12V cooling fan
Heat resistant foam
2x Large paper clips
1/8" long machine screws
Control Circuit Materials:
555 Timer IC
8 pin IC socket (optional)
100kohm potentiomenter (variable resistor)
Potentiometer knob (optional)
47 microfarad capacitor
Printed Circuit Board
IRF510 Power MOSFET
Quick disconnect power connectors
18 gauge connector wires
12V LED Lamp (or standard LED and resistor)
Insulated project enclosure
Drill and bit set
Soldering iron and solder
machine screw tap or spare machine screws