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Splashpower Boasts Wireless Power
Sullivan writes "Maccentral is running a story on a startup called Splashpower that hopes to be able to wirelessly recharge all of our handheld devices. They have a working prototype that already recharges an iPod Mini and a cell phone. Now we can look forward to yet another way to get brain cancer."
still, i'd like it if this became mainstream.
philo
My electric shaver recharges this way, and i've been wondering why we don't just have a pad that we can toss our electric gadgets onto for recharging.
My wish has been granted!
As for efficiency, I'll refer you to DansData, because he knows the answer to everything.
Your Answer Here
[Fuck Beta]
o0t!
Yes they did prove it...at least my college physics prof did by using a hypothetical line 1 foot above your head carring an impossible amout of power (1 million volts or somthing silly like that). The magnetic field generated by the line was several orders of magnitude less than the magnetic field of the earth which you are exposed to at all times.
Also the cell phone brain cancer thing is becoming less and less likely.
Apple free since 1990!
You mean like this?
To that point, when I plug a battery into a charger, there are no "wires" between the battery and the charger either. So I guess most battery chargers where the battery or device is placed into the charger are all wireless as well...
OTOH, this maybe a bit more refreshing.
The Earth's magnetic field is really really weak at the surface - like 30-40000 nano tesla, depending on where you are. We get exposed to many fields that are significantly stronger all the time (I definitley do - but then I work in a lab where we have several 1-2 tesla magnets going fairly often; on the otehr hand, we also have a shielded room, so I don't get exposed to Earth's magnetic field for significant portions of my day).
Also, you're going to get less than .7 efficiency from the inductive recharger. The .7 efficiency on something like a toothbrush-charging stand assumes that the coils actually overlap slightly (know that little knob that the toothbrush rests on? It's actually part of the magnetic core that helps transmit the AC over). The electric field decreases with the square of distance. In one of those toothbrush chargers, the inductors are separated maybe by a millimeter of thin plastic. If you have... say a mousepad-sized recharging "station" to put all of your goodies onto, you might end up with distances of several inches from the charging coil to the pickup coil in the device you actually want to charge. Without having an actual "stand" like electric toothbrushes do, you aren't going to transmit much power. If you're going to have a stand, might as well have metal contacts, and forego the less efficient inductive method. The only reason why toothbrushes really do that is because they're often wet, and you put them in your mouth, so you wouldn't want metal contacts sticking out (my waterproof electric razor actually has metal contacts, you just wouldn't want to plug in the AC while it's wet).
Nothing says "unprofessional job" like wrinkles in your duct tape.
But two questions: First, was it alternating current? And second, how much amperage was going through the line?
Just having 1,000,000 volts above your head means nothing if there's little amperage and it's a DC power source. Alternating currents cause electromagnetic fields to propogate, and large amounts of current causes them to be more powerful. This is why you can get a flourescent tube to light up when you stand underneath high power transmission lines - The electromagnetic field from them is inducted into the tube and there is still enough power to excite the mercury atoms. Last I checked the Earth's magnetic field couldn't do something like that...
I can see why the brain cancer/cell phone controversy exists - Basically you have a very, very powerful source of EM in a concentrated spot next to your ear. The problem is that nobody can seem to prove conclusively that it causes cell mutations.
-R
Umm, because in AC the magnetic field is changing, which flourescent bulbs require to operate?
The earth also has an electric field of about 100 volts per meter, so the potential at your feet (if you're an average-sized adult) is different from that at your head by about 200 volts. Doesn't cause cancer.