Cool idea: gravity powered LED light

Daox · 12-15-12, 07:11 AM

The wonders that are LEDs have allowed us to do some pretty cool things like make the shaker and crank flashlights. Well, a company has made another pretty cool LED light that uses gravity to power an LED lamp/light. You basically hang the lamp and then hang a weight off of it. The weight spins a generator and provides power to the lamp. To recharge the lamp, you simply lift the weight back up. Its only a few pounds, so its real easy to do. The gravity light can also be hooked up to other things to recharge them. Its pretty cheap too. Pretty cool idea IMO.

GravityLight: the low-cost lamp powered by sand and gravity | Art and design | guardian.co.uk

Daox · 12-30-12, 02:13 PM

Looking at this, there has to be a somewhat simple way of calculating how much energy is stored in X weight at Y height. Anyone know what that might be?

Fornax · 12-30-12, 04:28 PM

Indeed it's quite simple: E = m * g * h
E = energy (measured in joules)
m = mass (in kilograms)
h = height (in meters)
g = gravity acceleration (about 9.81 m/s^2 (at sealevel), often rounded to 10m/s^2).

So a weigth of 0,1kg (3.53oz) dropping down 1m (3.28') gives you 1 joule of energy, which is 1 watt/h for the duration of 1 second.
If you take a weight of 4 pounds (1,8kg) and raise it 1 meter 10 times and store the energy from dropping it down you now have 18J stored, with that you can let a 0,5W lightbulb shine for 36 seconds (E = 1,8 * 10 * 1 = 18J).

This formula is the same for hydroelectric plants, that is why the dam needs to be high and there has to be a lot of water. 1 megawatt = 100m3/s * 10m *g = 5m3/s * 200m *g.

Daox · 12-30-12, 05:26 PM

Haha, yes that is indeed a humbling formula! So much weight, or height is required to get so little power (compared to what we use daily). Its pretty crazy.

NeilBlanchard · 01-18-13, 01:27 PM

I missed this until today - the inventor was on Science Friday just now:

Inventors Design Lamp Powered Entirely by Gravity

They will be doing a crowd funding, where if you want one, you essentially pay for two, and they donate one to a deserving person in a place where they live off the grid.

12-15-12, 07:11 AM	#1
Daox Administrator Join Date: Aug 2008 Location: Germantown, WI Posts: 5,525 Thanks: 1,162 Thanked 374 Times in 305 Posts	Cool idea: gravity powered LED light The wonders that are LEDs have allowed us to do some pretty cool things like make the shaker and crank flashlights. Well, a company has made another pretty cool LED light that uses gravity to power an LED lamp/light. You basically hang the lamp and then hang a weight off of it. The weight spins a generator and provides power to the lamp. To recharge the lamp, you simply lift the weight back up. Its only a few pounds, so its real easy to do. The gravity light can also be hooked up to other things to recharge them. Its pretty cheap too. Pretty cool idea IMO. GravityLight: the low-cost lamp powered by sand and gravity \| Art and design \| guardian.co.uk __________________ Current project - To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts. To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts. & To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.

12-30-12, 02:13 PM	#2
Daox Administrator Join Date: Aug 2008 Location: Germantown, WI Posts: 5,525 Thanks: 1,162 Thanked 374 Times in 305 Posts	Looking at this, there has to be a somewhat simple way of calculating how much energy is stored in X weight at Y height. Anyone know what that might be? __________________ Current project - To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts. To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts. & To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.

12-30-12, 05:26 PM	#4
Daox Administrator Join Date: Aug 2008 Location: Germantown, WI Posts: 5,525 Thanks: 1,162 Thanked 374 Times in 305 Posts	Haha, yes that is indeed a humbling formula! So much weight, or height is required to get so little power (compared to what we use daily). Its pretty crazy. __________________ Current project - To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts. To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts. & To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.

12-30-12, 04:28 PM	#3
Fornax Helper EcoRenovator Join Date: Oct 2012 Location: Beuningen (Gld), the Netherlands Posts: 64 Thanks: 4 Thanked 19 Times in 16 Posts	Indeed it's quite simple: E = m * g * h E = energy (measured in joules) m = mass (in kilograms) h = height (in meters) g = gravity acceleration (about 9.81 m/s^2 (at sealevel), often rounded to 10m/s^2). So a weigth of 0,1kg (3.53oz) dropping down 1m (3.28') gives you 1 joule of energy, which is 1 watt/h for the duration of 1 second. If you take a weight of 4 pounds (1,8kg) and raise it 1 meter 10 times and store the energy from dropping it down you now have 18J stored, with that you can let a 0,5W lightbulb shine for 36 seconds (E = 1,8 * 10 * 1 = 18J). This formula is the same for hydroelectric plants, that is why the dam needs to be high and there has to be a lot of water. 1 megawatt = 100m3/s * 10m g = 5m3/s 200m *g.

01-18-13, 01:27 PM	#5
NeilBlanchard Journeyman EcoRenovator Join Date: Dec 2009 Location: Maynard, MA Eaarth Posts: 383 Thanks: 78 Thanked 39 Times in 32 Posts	I missed this until today - the inventor was on Science Friday just now: Inventors Design Lamp Powered Entirely by Gravity They will be doing a crowd funding, where if you want one, you essentially pay for two, and they donate one to a deserving person in a place where they live off the grid.