Connected devices and the "Internet of Things"—in which everyday objects are networked to allow them to communicate without human interaction—were a dominant theme at this week's CeBIT, a leading technology fair held in Hanover, Germany.

From connected sneakers to robots, CNBC takes a look at some of the hottest products from CeBIT, which make the future look closer than you think.

—By CNBC's Arjun Kharpal at CeBIT in Hannover on Wednesday March 18, 2015.

Nowadays, pretty much anything can become a connected device—and that includes shoe insoles.

Users can connect the Digitsole to their Apple iOS or Android device and use it to increase the temperature of the insole in order to warm their feet. The Digitsole can also track steps and the number of calories burned.

The device can be put into any piece of footwear, essentially making your shoe collection a bunch of connected devices.

Neuro:On is an "intelligent sleep mask". The $299 device is sophisticated enough to track metrics such as sleep waves, eye movement, muscle tension, heart rate, and blood saturation.

The device, which connects to a user's smartphone, has an alarm which detects the best time to wake a user up, depending on metrics such as eye movement.

A light will gradually appear in the sleeper's eyes and get brighter to imitate natural daylight. If the user does not wake up, the neuro:On will begin to vibrate—eventually an alarm will go off.

The start-up raised $438,573 on crowdfunding platform Kickstarter last year, smashing its $100,000 target.

Homey lets your control all the devices in your home with your voice.

The glowing orb can connect to many different aspects of a home, such as lighting or television. Users say the trigger phrase "hey Homey" to begin giving voice commands and Homey will trigger the action asked for, such as, turning the lights down.

The 299 euro ($317) device was initially crowdfunded on Kickstarter last year. It raised 203,918 euros, surpassing its goal of 100,000 euros.

This giant installation of robotic arms could give a glimpse of the future of manufacturing.

People can use the ROBOCHOP app to create a design on a 40 x 40 x 40 centimeter (16 inch) polystyrene block. The robots then cut the block using a hot wire tool and the finished block is sent to the user by post.

The company hopes the tool can be used to make manufacturing processes easier in the future.

"ROBOCHOP envisions a not-so-distant future where intelligent systems empower anyone to directly engage with heavy industrial manufacturing technologies," according to the company's website.

It may raise security concerns, but this app means your door can be unlocked with just a smartphone.

Australian start-up Digital Keys has developed an app that can unlock doors by tapping a smartphone to the lock. It uses "near field communication"— technology that powers contactless payment systems like Apple Pay.

Digital Keys says it's hoping hotels will use the app to send a unique passcode to guests, so a person can walk into a hotel and go straight to their room.

Retailers are forever looking at ways to make their physical stores more appealing, as customers increasingly opt to shop online.

Magic Schaufenster thinks it has the answer, in the form of a gesture-powered advertising device. The company has produced a large electronic board that can be placed in a shop window and begins playing advertising as a person approaches.

Shoppers can also stand in front of the board, and—by using gesture control—try on different outfits virtually.

The 7,500 euro ($7,954) device is expected to retail next year. Mesut Yilmaz, managing director of Magic Schaufenster, told CNBC the product would be a "customer magnet"— but the market for "smart" retail devices is very competitive, with tech giants such as Samsung also moving in.

"Smart" cities that use digital technology to reduce costs and enhance wellbeing are a hot topic, with a whole host of companies looking to make the vision a reality.

One is German utility firm EnBW, which has created SM!GHT, a smart street light. It provides free WiFi for people on-the-go in the city, a charging slot for electric vehicles and an SOS button that calls the closest emergency service provider.

Cozify is another company offering a product that allows users to control all their "smart" home devices through a single hub.

Its 149-euro ($158) piece of hardware can connect you to all smart home devices—such as lights, or TV—through a single smartphone app. You can also buy sensors that can be programmed to turn on lights as soon as you enter a room.

The company hopes to partner with smart device makers and major retailers to get the Cozify hub into stores. Tony Risikko, co-founder of Cozify, told CNBC that while there were a lot of players in this space, very few such products were actually sold in the stores where people bought their smart devices, meaning the market was unsaturated.