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Possibly the best USB device ever invented!
- Thread starter A-Dub
- Start date
- Joined
- Dec 16, 2007
- Location
- Chicago, IL
Now I just need a USB George Forman Grill.
- Joined
- Mar 6, 2004
- Location
- Rockingham, NC
I would still almost kill for a coffee warmer that actually kept it hot.
- Joined
- Oct 11, 2005
- Location
- Tau'ri
well this bad boy should nuke a cup of coffee up pretty good 
- Joined
- Apr 6, 2009
- Location
- Northern Virginia
mwave once had some USB slippers.
- Joined
- May 15, 2009
- Location
- Suffolk UK
Problem is that by the time it gets out we won't care anymore
2012 at least.
2012 at least.
- Joined
- Jun 1, 2001
it must have an external power supply, becuase standard usb port is not powerful enough to heat anything up. they are claiming 60 second cook time for a typical snack. at that speed it would need to consume at least 100w of power, weither it works by cell carrier frequency or conventional microwave using a magnetron, voltage converter, high V cap, etc.
theres no way a usb port alone can power that.
theres no way a usb port alone can power that.
- Joined
- Aug 1, 2002
- Location
- Michigan
4 different USB ports = 2A max (for example) and it may power a low power heating element reasonably but I doubt the claim of 60 seconds unless I see it first hand.
Even peltier needs a lot more than 2A to heat a cup of coffee in 60 seconds.
Even peltier needs a lot more than 2A to heat a cup of coffee in 60 seconds.
- Joined
- Sep 20, 2007
Exactly what I was thinking too, NO way that is going to Power it from USB
- Joined
- Feb 26, 2003
Maybe it uses the USB to charge an element / battery system prior to actually working?
- Joined
- Jun 9, 2001
- Location
- Montreal, Quebec, Canada
Natcho cheese anyone?
- Joined
- Oct 19, 2006
- Location
- Rochester, MI
Even so, it would still kill any laptop battery very quickly. It takes a considerable amount of energy to heat a cup of coffee just 10 degrees. A stupid invention if you ask me.
EDIT: I just did the calculations. To heat 10 ounces of coffee 20 degrees C requires about 23.4KJ of energy or about 6.5 watt-hours of energy assuming 100% efficiency. Assuming an efficiency of about 60% (more realistic) that's about 10.8Wh of energy for that one cup of coffee. The battery on my samsung X460 has a capacity of about 49Wh so its a bit impractical for it to be powered from a laptop.
EDIT: Screwed up my numbers. Thanks JigPu.
Last edited:
- Joined
- Jun 20, 2001
- Location
- Vancouver, WA
Not sure your calculations are quite correct Tophinater... I get the following:
Specific heat of water: 4 J*g⁻¹*K°⁻¹
Density of Water: 1 g*mL⁻¹
USB voltage: 5 V
Mass of 300 mL water: 300 mL * 1 g*mL⁻¹ = 300 g
Energy to raise 300 g of water 20 K°: 4 J*g⁻¹*K°⁻¹ * 300 g * 20 K° = 24 kJ = 6.6 W * h
Power required to produce 24 kJ of energy in 60 seconds: 24 kJ / 60 s = 400 Watts
Amperage required to produce 400 W over USB: 400 W / 5 V = 80 Amps
Capacitance required to hold 24 kJ of energy at 5 V: 24 kJ / (5 V)² = 960 Farad
Capacitance required to hold 24 kJ of energy at 200 V: 24 kJ / (200 V)² = 0.6 Farad
~~~~~~~~~~~~~~~~~~~~~
I'm a little leary of this microwave...
Clearly the USB port can't be the sole power source, since we'd need to somehow draw 80 amps. There can't be a capacitor bank inside of the thing because a 24 kJ bank is absolutely massive... A rechargeable battery would be the best bet since 6.6 Wh isn't much energy for a battery, but I'm still hesitant at you finding a way of pulling enough current from a battery that'd fit inside that thing
JigPu
Specific heat of water: 4 J*g⁻¹*K°⁻¹
Density of Water: 1 g*mL⁻¹
USB voltage: 5 V
Mass of 300 mL water: 300 mL * 1 g*mL⁻¹ = 300 g
Energy to raise 300 g of water 20 K°: 4 J*g⁻¹*K°⁻¹ * 300 g * 20 K° = 24 kJ = 6.6 W * h
Power required to produce 24 kJ of energy in 60 seconds: 24 kJ / 60 s = 400 Watts
Amperage required to produce 400 W over USB: 400 W / 5 V = 80 Amps
Capacitance required to hold 24 kJ of energy at 5 V: 24 kJ / (5 V)² = 960 Farad
Capacitance required to hold 24 kJ of energy at 200 V: 24 kJ / (200 V)² = 0.6 Farad
~~~~~~~~~~~~~~~~~~~~~
I'm a little leary of this microwave...
Clearly the USB port can't be the sole power source, since we'd need to somehow draw 80 amps. There can't be a capacitor bank inside of the thing because a 24 kJ bank is absolutely massive... A rechargeable battery would be the best bet since 6.6 Wh isn't much energy for a battery, but I'm still hesitant at you finding a way of pulling enough current from a battery that'd fit inside that thing
JigPu
- Joined
- Oct 19, 2006
- Location
- Rochester, MI
Yep, your right. I accidentally used the specific heat from air from doing other calcs in the cooling forum.
Anyway, I get the same numbers you do. 23.4 KJ for 100% efficiency which would require a 936 Farad cap. In order for this thing to work it would have to have its own rechargeable battery which would be stupid because then you would be charging a battery from another battery. If this is the case it wouldn't need to draw 80 amps, just charge the battery in the microwave for a period of about 2.5 hours assuming a 0.5 amp draw. It would then draw the power from its own battery when operating. However, an even bigger question is how do you get the 5V from the USB port to the, I'm guessing, hundreds of volts for their modified magnetron/emitter.
- Joined
- Jan 11, 2004
Clearly they will simple make an adapter to plug it directly into your new USB powered Mr. Fusion.
- Blackstar
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