Microsoft HoloLens, an augmented reality headset, is an early post-smartphone device. You interact with it by using its cameras and microphones instead of a touchscreen. TED It's the dawn of a new kind of computer. And a new kind of computer requires a new way to get stuff done.

Each new era of computing has brought with it a big change to how we interact with our devices. PCs ditched the punch card and gave us the mouse and keyboard. Smartphones got rid of the mouse and physical keyboard in favor of multitouch screens.

Get ready for touchscreens to fall out of favor soon too, as we enter the post-smartphone era. This period is likely to be dominated by everyday gadgets like speakers, eyeglasses, and even toasters that have been made "smart" with powerful computing chips, wireless communications radios, and sensors.

You're not going to attach a mouse and keyboard to your connected toaster, and you're not going to poke around on a touchscreen while you're attempting to repair an elevator with the help of some smart glasses.

The good news is you may already be prepared for the change. If you've ever sent your significant other a picture to make sure that you picked up the right cereal or used Siri to answer a text while you were cooking, you've already taken some early steps into the post-smartphone world.

That's because the camera and microphones are likely to be the new mouse and keyboard. They'll be how we interact with these new smart computing devices, in large part because they too are getting smarter.

Listening and talking

Microphones and cameras have a lot of appeal as interfaces for computers, because they tap into the human brain's natural modes of communication, noted John Underkoffler, an award-winning computer interface designer who helped envision the iconic computing systems used in "Minority Report" and the "Iron Man" films.

When you have face-to-face meetings with people, you're not just listening to what they say; you're inferring meaning from their facial expressions, hand gestures, and overall body language. Communication is visual and verbal.

Using Google Translate to translate a street sign using the camera and your phone's screen. Google

Smarter, cheaper microphones and cameras will allow us to have more natural interactions with more and more of our devices. And they'll allow us to do things that just weren't possible before.

Take Google Translate as example of what cameras and microphones can make possible. You can speak a phrase into your smartphone's mic and have Google Translate's app instantly translate it into another language. Or you can hold your phone's camera up to sign in a foreign country and the app will quickly show you what it means.

Microphones and cameras are "going to be part of a new wave of user interface that's going redefine what computing means," Underkoffler said.

Smarter everything

A great early example of how we'll be using cameras and microphones to interact with post-smartphone devices is Amazon's Echo Show. Like other Echo devices, the Show is a smart speaker that's powered by Alexa, Amazon's voice assistant. What's most obviously different about the Show is that it has a screen; you'd be forgiven for thinking it looks a little like an iPad in a heavy case.

But what makes the Show particularly interesting is how you interact with it. Its display is a touchscreen, so you can, of course, tap on virtual buttons and commands. But that's not how you'll likely use it most of the time.

Instead, its primary interfaces are through its microphone and cameras. If you want to know the latest news, watch Amazon Prime videos, or find out the score in your team's game, you'll likely just talk to the Show. If you want to see if Amazon has your shampoo in stock, you can use the Show's camera to scan in an old bottle, identify it, and find it in the store.

Using the Amazon Echo Show as a makeshift karaoke machine. Matt Weinberger/Business Insider

You can also use the microphone and camera together. You can tell Alexa to take a selfie of you, for example, or have her initiate a video call to your mom.

Such features are especially popular with the elderly, particularly people who struggled to master a smartphone or a PC, said Miriam Daniel, Amazon's director of Echo devices and Alexa. For them, it's much easier to just ask Alexa to do something than to figure out which app to use.

Daniel said the Echo Show and similar devices are also proving popular in emerging markets like India, where PCs never really caught on widely and modern smartphones are only starting to gain significant traction. For consumers in such countries, post-smartphone devices like the Show could be the only computer they end up needing, she said.

But the Show offers only a taste of what's to come in terms of how we interact and what we'll be able to do with post-smartphone devices. A more sophisticated vision comes in the form of Microsoft's HoloLens.

The augmented reality headset uses a camera, mounted on its side, to "read" the world around you and help shape the digital images it displays. And, because it has a microphone, it will also respond to voice commands; you can tell it to check and display your email, for example.

Even though cameras and microphones are coming to the fore, touchscreens likely won't disappear. We'll still need them in some situations, just like we still use keyboards and mice today. Voice can't communicate everything, and cameras need some kind of screen to display the images and video they capture.

The camera and microphone do, however, offer users and new computing devices far more ways for communicating with each other.

"I think we're just scratching the surface of what we can do," Daniel said.