Log on and help save the planet. That, at least, is the basic idea behind EarthHack, an online contest in which anyone can suggest how to use existing technologies in slightly different ways to reduce global carbon emissions and move toward more sustainable energy sources.

EarthHack can be found Marblar, what Earthhack organizers call a “global crowdsourcing platform,” a means of gathering ideas from a large group of people online.

“People are looking for affordable and simple solutions to help them live a more sustainable life at home,” EarthHack’s home page says. “But unfortunately, many sustainable products and solutions are priced at a premium. Moreover, there are many existing technologies that have been developed for other purposes that can be re-imaged as sustainable solutions.”

Ideas collected now will be reduced to finalists on Aug. 1, with final submissions by Sept. 4, and the presentation of the winning idea in New York City during Climate Week Sept. 23 through 29. The winner gets $15,000.

Post your own ideas, comment on others

EarthHack allows anyone who registers to submit their own ideas for saving energy and reducing carbon emissions as well as comment on ideas that have been posted by other people.

The goals are to:

• Reduce energy consumption, and manage or generate energy more efficiently.
• Make lighting more efficient.
• Reduce household waste and cut the amount of waste going to landfillls.
• Save water and minimize the use of chemicals in the home

Entries are roughly divided into three categories: design, materials and systems.

Ideas are posted in the “Brainstorm” area, where icons indicate how many times each has been viewed, how many positive votes the idea has received, and the number of people who have posted comments on the idea.

Here’s an example. A student named Wyatt Felt proposes a shower head that calculates how much water is being consumed and reports this to the user via LED lights. In other words, the person standing in the shower can look at the shower head and get an idea of how much water he or she has used up.

“This creates a feedback loop that can coach the user toward a more sustainable shower habit,” Felt writes. “This could be especially valuable for kids learning to shower on their own.”

A diagram posted with the idea shows how the device would work: water flow generates electricity which is read by an electronic sensor and displayed in real-time by an LED display around the rim of the shower head. Felt’s idea generated 714 views, 12 votes and 11 suggestions for improving it.

By July 10, a total of 193 ideas had been submitted. Topics that ranged from fluorescent coatings for windows and solar food-drying kits to the use of a hydrophobic coating to reduce water consumption for cleanups.

Turning ideas into reality

The winner gets a wad of cash and a free ride to New York City. Second and third place finishers also win cash awards.

As interesting, EarthHack says it hopes that its industry partners (IKEA, The Climate Group and Philips) can help develop at least the winning idea into an actual product.