Usb human heater

Projects
Participants	Amx109
Skills
Status	Planning
Niche	Electronics
Purpose	Fun

After seeing the latest in hipsterly-wanky-named products, and suffering from cold hands all the time, i thought - why not build my own.

this is an attempt

Research

from [1]

In other words, on average the skin absorbs about 80 mW/cm2 to reach 41oC. In addition, skin temperature increases by 0.8oC for each 10 mW/cm2 of absorbed power.

Materials

http://www.conrad.nl/ce/nl/product/429066/Weerstandsdraad-63-m-5-m http://www.conrad.nl/ce/nl/product/429023/Weerstandsdraad-10-m5-m

Heating Element

P = VI
V = IR

65ohm/m

Voltage: 5V
Resistance: 65ohm
Current: ?

Length = 0.5m
Current = 5/32.5 = 0.156A
Power = 5 * 0.156 = 0.78W

10ohm/m

Voltage: 5V
Resistance: 10ohm
Current: ?

Length = 1.5m
Current = 5/15 = 0.333A
Power = 5 * 0.333 = 1.665W

Length = 2m
Current = 5/20 = 0.25A
Power = 5 * 0.25 = 1.255W