Professional photographers take off-camera lighting very seriously. They use a variety of light meters to ensure that the picture captured has the right tone, quality, and exposure.
Wearable devices with light sensors can be used to measure specific light patterns. Such devices can help amateur photographers with their camera lighting techniques and make sophisticated lighting accessible to the masses.
Wearable devices were first adopted in the military in the form of helmet-mounted displays that relay vital information to soldiers in the field. A soldier's life relies on critical information being delivered at the right time. A few companies grabbed this opportunity and built their own software and hardware ecosystems for the wearable device to work effectively. This created a huge entry barrier for smaller companies that couldn't build entire ecosystems. KitKat provides the military with a unified and open platform for development of wearable devices.
With the new sensor support in KitKat, expect Android gaming wrist bands with remote-control features and integrated consoles. Instead of holding a controller/remote in your hand, all you'd need to do is wave your hand and point to shoot -- a dream for every gamer.
Challenges for developers
There are many potential applications for wearable devices and almost as many challenges in developing them. The challenges vary all the way from hardware capability to technical expertise.
From a hardware perspective, the expectations of ruggedness for wearable devices will be higher than that of a smartphone. Smartphones are built for computing and can run a lot of applications, but they're personal and fragile systems. Wearable devices won't operate in such a gentle environment. A simple example is the inability to operate touchscreens in dust/dirt conditions or while wearing gloves. To meet the requirements of wearable devices, it's important for designers to look beyond a delicate screen on a wrist.
The probability that your company has the experience and expertise in all domains of Android development is pretty small (unless you're Google). It becomes extremely important to have a sustainable pool of engineers with multiple skillsets to conceive your ideas from paper to actual products. With Android development on wearable devices picking up pace, the demand for skilled and seasoned engineers will only increase.
With new versions of Android releases and with devices not being up to date on the version of software, the permutations of devices and Android versions will grow exponentially. This might not be much of a concern for simple apps, but it's a tsunami of support for specialized apps.
A simple example to consider: Company A makes AppA, which many people have been using regularly. Company B makes AppB, which is recognized but not very well adopted. There's an Android update, and both companies find that their apps are rendered useless on the new version. Company B hires 1,000 engineers to make sure its application is up and running on the latest version. Company A tries to resolve the issue through its current set of engineers. If Company A doesn't deliver before Company B, users may switch to AppB from AppA.