Tap an app to switch on your lights

• The Philips Hue system turns lights on and off%2C dims them and changes colors
• The new Lifx bulb is pricey but doesn%27t need to connect to router
• The cheapest and easiest connected device is Belkin%27s Wemo

LOS ANGELES — So who really needs light switches anyway?

With a smartphone app, you can turn lights on and off and even change their colors from bright white to any hue of the rainbow.

That is the concept behind "connected" light systems from Philips with its $199 Hue, which changes colors, and Connected by TCP's $149 system, which just turns them on and off.

Both work by connecting to a home Wi-Fi router.

A new company, Lifx, offers a pricey $89 LED bulb that turns on and off and changes colors, but it doesn't need to be connected to a router. And if you want to join the party but spend a lot less, the Belkin Wemo system is the simplest and most affordable at just $49.

Plug the Wemo switch into an AC outlet, and add a lamp or another device. Download the app and you can turn products on and off. (It does get more expensive if you add multiple Wemo switches around the house.)

Why the interest in connected bulbs?

"It's the features," Lifx CEO Phil Bosua says. "The amount of things you can do with a connected bulb that you can't with a standard bulb is just awesome. You can be in bed, reach for the smartphone and turn off every light in the house."

A closer look at what's available:

— Connected by TCP Wireless is a $149 kit that comes with three LED bulbs and a hub that connects to your home router. Download the app and you can turn lights on from anywhere.

— Phillips HUE. A starter kit with three LED bulbs and a base station that connects to a router sells for $199. Turn lights on and off, dim them and change colors as well, via the Hue app.

— Lifx. Buy bulbs separately, without having to connect to a router. Download the app, and turn the LED lights on and off and change colors. Lifx was first introduced on Kickstarter in 2012, where it raised more than $2 million. It's available now via Amazon and will be sold in Best Buy stores in 2014.

— Wemo Switch. No need to involve a router with the Wemo device. Just plug it into an outlet and then plug in a lamp or other small appliance to turn it off or on with the app.

"I don't think anybody would say a slow cooker is an integral part of the smart home, but when you think about it, the sky's the limit," says Ohad Zeira, a Belkin product manager.

Finally, for those who have too many connected devices in the home, and too many apps to operate them, comes Revolv. It's a new unit that tracks all the devices — from a Roku media streaming box and Nest thermostat to the Wemo or Hue. It operates them from one central location.

You buy the Revolv hub for $299, plug it into the router, and use the Apple app to operate them all.

"We're starting to see the connected home become a reality," says Mike Soucie, the co-founder of Revolv. "The next step is app fatigue. There's just too many of them, so we tried to have them all under one umbrella. We support 50 devices now and will support hundreds more in the coming year."