Im building a altoids tin sized pocket arduino computer with wifi and a few other features i was recently thinking about using qi charging as to keep the ports on thedevice to a minimum. I was wondering if any one had tested if the radio waves such as qi are able to go through a mental such as aluminium.
Radio waves do not go through metals.
You may see people wearing tin foil hats -- now you know why!
Oh => thanks for the info i guess thouse hats make a slight bit more sense now... when i do it ill see if using holes in the thin will work... if not i can use it as speaker holes
For radio to go through a hole, the hole must be bigger than the wavelength. Very high frequency has a wavelength about 2 meters. Is that size hole possible in your tin?
I don't know what frequency qi uses.
Ah i see... well i guess the hole idea is out then... considering the device its self is less than two meters...What i think ill do is put the qi pad on the outside of the device... they tend to be covered in plastic and tend to be waterproof
A QI pad uses magnetic induction, not radio, and magnetic fields will "go through" thin layers of nonferrous metals.
jremington:
Radio waves do not go through metals.You may see people wearing tin foil hats -- now you know why!
We are talking near-field, not far-field. Anyway RF fields do penetrate into metals, but decay
due to the skin-effect so than even thin metal foils can stop normal RF frequencies with great
efficiency. With far field both magnetic and electric fields matter, with near field only the magnetic
field matters (electrostatic shielding per se isn't an issue)
50kHz inductive power transfer will go through thin foils, but a lot of power is also reflected
and absorbed which increases losses. Iron or steel will absorb nearly all the power as heat
very efficiently as they are ferro-magnetic - this is how induction hobs and induction welding
work.
I see... my knolage on radio and rf is very minimal so ill have to see if the the thin tin can has enough of a difference for me to not use it on the inside
Iron or steel won't work, I said this already, you'll just heat up the tin.