Serial entrepreneur Gene Wang started People Power, a maker wireless network devices that monitor energy consumption, because he knows how much energy is wasted by the average household. Thermostats are not set properly, TVs draw power even when they’re off and sprinkler systems operate oblivious to weather patterns.

“About the dumbest thing you see happening is it’s raining and your lawn sprinklers turn on because they’re just on a timer,” said Wang, founder and CEO of People Power, who said People Power’s sprinkler system device is being developed with a sensor that could tell if your lawn is already wet.

What makes the company special, in an increasingly crowded field of home energy management startups, is that it wants to allow the developer community to build on top of its sensor technology. Today, it announced that it will start selling $150 software development kits on March 31 — giving inventors all the tools they need to create wireless energy sensors for various home appliances and applications.

Based in Palo Alto, Calif., People Power calls its SDK the SuRF Developer’s Kit, which stands for Sensor Ultra Radio Frequency. The company uses a surfing theme throughout: the circuit boards on which developers can build a device are called SuRF Boards; it’s sponsoring a SuRFing Contest with a prize going to the maker of the cleverest device; and its open-source platform for the devices is called the Open Source Home Area Network, or OSHAN (pronounced ocean).

“We are helping people ride the big green wave,” Wang said.

Just as the rise of gasoline prices to nearly $5 a gallon in 2008 spurred sales of hybrid cars, Wang believes that the average 22 percent increase in electricity rates over the last two years will spur interest in smart grid devices in the home.

The brains of the SuRF wireless sensor platform is a Texas Instruments TI-CC 430 system on a chip that combines the microprocessor and the radio. A network of sensors placed around a house, connected to appliances like your dishwasher or thermostat, could monitor energy use. It could also automatically turn down the heat or air conditioning in an unoccupied room, or shut off power to an outlet where a TV or computer is plugged in but not on.

One key feature of the SuRF platform is that the radio operates at 900 megahertz (MHz), a lower frequency than the 2.4 gigahertz (GHz) at which many electronic devices operate, such as Bluetooth headsets, Wi-Fi access points and microwave ovens. Wang said they went with 900MHz because it gives the senors’ signals longer range.

“I think we’ve been trained by Intel to believe that faster is better, but the reality is, based on the laws of physics, the lower the megahertz, the longer the range,” he explained. The longer range is needed so the sensors not only connect to each other but also to the electric meter outside the home. And running at 900MHz means the signals more easily penetrate walls and can operate at low power so they’re not contributing to the problem of high energy use.

The operating system used in the platform is TinyOS, which is the OS for a million sensors already on the market. It has a developer community of 10,000 people.

Part of the development funding for the SuRF SDK came from $150,000 in stimulus funds from the U.S. Department of Energy. Wang called that a phase one grant, and said that a second phase grant to People Power will probably amount to $1 million.

Of the $787 billion stimulus bill, about $80 billion of it is going to smart grid energy projects, including wireless home sensor technology.

That funding has drawn interest from venture capitalists who have invested in green technology startups before, including People Power backer New Cycle Capital.

New Cycle Partner Josh Becker wouldn’t disclose how much the firm has invested in People Power, but said it has raised $30 million from its limited partners to invest in eight green tech companies, so far. He said he sees many plans from other startups in the home sensor space seeking funding.

“Everyone realizes it’s a massive opportunity to show how to decrease energy use in the home and so, yes, we’ve seen a lot of different plans in this space,” Becker said.

At the IDC Directions 2010 conference last week, IDC analyst John Gantz forecast that by 2020, the world will be populated by 23 billion sensors, including in the home, as the world evolves “from an internet of computers to an internet of things.”

Gantz also mentioned a project at HP Labs that envisions a trillion-sensor network. HP calls its sensor project the Central Nervous System for the Earth (CeNSE). Sensor technology for energy conservation is also being developed in a big way for commercial buildings.