The Piezoelectric floor... once again
- Thread starter anfedres
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A 2500 mAh, 1.5V AA cell contains a nominal 3.75 watt-hours. It'll take at least about 8Whrs of charge energy to charge it up, probably a bit more but let's be generous.
There's an MIT report of using a piezoelectric transducer in a shoe, and they reported an average power capacity of 60µW at 1 Hz, which is in line with what others have reported. For instance, Piezo Systems says a 1.5" x 2.5" x .0075" transducer can give 3.6mW at 60Hz. That's a lot higher, but in a lab setting. That same source notes that, in principle, the transducer could produce 9W out of more than 100W of mechanical input. This shows how poor the return of energy is.
Again being generous, let's say we can get (and capture) 0.1mW out of a floor-mounted transducer receiving frequent foot traffic. The math says we would need 10,000 transducers, over 260 sq.ft., to charge our AA in 8 hours. I think that's plausible, easily off by 2X but probably not more than 10X
Not something I would spend my time on, but your mileage may vary.
There's an MIT report of using a piezoelectric transducer in a shoe, and they reported an average power capacity of 60µW at 1 Hz, which is in line with what others have reported. For instance, Piezo Systems says a 1.5" x 2.5" x .0075" transducer can give 3.6mW at 60Hz. That's a lot higher, but in a lab setting. That same source notes that, in principle, the transducer could produce 9W out of more than 100W of mechanical input. This shows how poor the return of energy is.
Again being generous, let's say we can get (and capture) 0.1mW out of a floor-mounted transducer receiving frequent foot traffic. The math says we would need 10,000 transducers, over 260 sq.ft., to charge our AA in 8 hours. I think that's plausible, easily off by 2X but probably not more than 10X
Not something I would spend my time on, but your mileage may vary.
Thanks guys of all the comments, at least this is going far with all the suggestions. But let's think for a second, how people are getting energy from Piezelectric discs??? Pavegen it's generating electricity from these little discs, with a little amount of current. So, let's try to figure out for a second how do they do it, it should be possible!!!!.
I'm just trying to find which is the best source to explore, today I got a supercap almost fully charged with a little Chinese lamp. Those ones that you have to press it to "charge" a battery, thing that is not true of course. But I disassemble it, and I took the dynamo out. I charged a 12000uF, and I used to turn on a led for about a minute.
I've been thinking a lot about this problem, and, well, It'd be challenging to do something very similar, but I wanna do it. I keep thinking about using a similar circuit like this one. I think that DC-DC converter will try to keep the voltage stable. I saw this harvesting circuit. But let's be honest, it's kind of expensive. And I'm living in Colombia, just the shipping will cost around $100.
Once again guys, thanks for all your comments, and please, let's keep posting our ideas about it, OK???.
I'm just trying to find which is the best source to explore, today I got a supercap almost fully charged with a little Chinese lamp. Those ones that you have to press it to "charge" a battery, thing that is not true of course. But I disassemble it, and I took the dynamo out. I charged a 12000uF, and I used to turn on a led for about a minute.
I've been thinking a lot about this problem, and, well, It'd be challenging to do something very similar, but I wanna do it. I keep thinking about using a similar circuit like this one. I think that DC-DC converter will try to keep the voltage stable. I saw this harvesting circuit. But let's be honest, it's kind of expensive. And I'm living in Colombia, just the shipping will cost around $100.
Once again guys, thanks for all your comments, and please, let's keep posting our ideas about it, OK???.
