Imagine the first time you built something out of Legos. Now imagine if each of those Lego bricks had a dedicated function -- such as a light, electrical generator, or a camera -- and it becomes easy to construct a wide variety of devices.

This concept of separating different functions into independent modules, known as "modular computing," has recently made waves in the technology sector thanks to its limitless potential for customization.

Could smartphones and wearable devices built on modular technology revolutionize medical devices as well? Let's look at two upcoming products from Google (NASDAQ:GOOG)(NASDAQ:GOOGL) and Toshiba (OTC:TOSBF) to understand how modular versions of smartphones and smartwatches could affect the health-care sector.

Is Google's Project Ara the ultimate consumer medical tool?
Google's Project Ara, a device that compartmentalizes its components in block-like modules, has recently generated a lot of buzz as the world's first mass-marketed modular smartphone, set to be released in early 2015.

The base unit of the phone, known as the "Gray Phone," costs a mere $50, but it consists of only a frame, screen, and Wi-Fi module. Users must purchase additional blocks, which are attached to the back, to add optional features such as a camera, motion sensors, and a GPS.

Google's Project Ara. Source: Wikimedia Commons.

Simply put, Google allows users to swap out components to create a smartphone as spartan or feature-rich as they desire. Google intends to launch the Gray Phone in January 2015, but it could face some pricing challenges there, as I mentioned in a previous article.

The main problem is that a $50 bare-bones phone still isn't priced competitively against Nokia's (NYSE: NOK) low-end Asha smartphones, which already offer cameras, motion sensors, location services, and wireless connections for $40 to $100.

Despite those challenges on the consumer front, Project Ara has a lot of potential uses in health care. Early developers have already showcased a pulse oximeter module for the device. Other ideas include a blood analysis module, glucose monitor, heart rate monitor, and combining several custom modules to build a medical tricorder similar to the Scanadu Scout. In other words, the Gray Phone base of the Ara could be connected to limitless modules to become the medical device equivalent of a Swiss army knife.

In this regard, Google could gain an edge over Nokia and Apple (NASDAQ:AAPL). Nokia's Asha phones are cheap, but they have tiny screens, low-resolution cameras, and weak processors that aren't designed to run medical apps or connect to peripheral devices.

Apple's iPhones and iPads are already compatible with a plethora of medical apps and peripherals, but they both cost much more than $50. Therefore, if Google is targeting lower-income markets with Project Ara, marketing it as a health-care "omnitool" could be a promising start.

Toshiba expands the idea to modular wearables
Toshiba, one of Google's Project Ara partners, is looking even further into the future with modular wearables. At the Ara Developer Conference this month, Toshiba Senior Vice President and Technology Executive Shardul Kazi demonstrated how the modular design of the Gray Phone could be used on a wearable fitness band or smartwatch.

Kazi specifically discussed the use of Bluetooth LE connections and activity tracking modules with nine-axis sensors, but the possibilities are tantalizing. For example, Google and Toshiba could release a base fitness band with a dozen empty sockets. Customers could then buy specific modules -- say, a watch, a motion sensor, a heart rate monitor, or even a glucometer -- and plug them in as needed. It would be a fully customizable smartwatch. It's an intriguing concept that start-up Blocks has also been exploring.

By comparison, Nike's FuelBand and Samsung's Galaxy Gear suddenly seem almost outdated. Modular wearables and smartphones might even affect Apple's long-rumored plans to make the iPhone 6 a health-centric device with a companion smartwatch.

The challenges ahead
Modular technology certain sounds promising, but it has some big hurdles to overcome.

With the success of the Mac, iPad, and iPhone, Apple proved that consumers don't want to swap out components as they did in the early days of computing -- they just want a product that works. While the idea of a DIY smartphone or smartwatch will appeal to tech-savvy hobbyists, the concept might seem unnecessary and complicated to others.

Nonetheless, Project Ara could eventually pave the way for a new generation of Lego-like smart medical devices to hit the market, and forever change our perception of the role of smartphones and wearables in medicine.