There is no denying the phenomenal growth the digital health market is seeing. While significant dollars are being poured into developing software-only solutions, such as decision support systems or practice management tools, much of the activity involves some kind of device--either wearable or handheld. Many businesses are focusing on devices that measure, track, or monitor some metric. Connectivity—most of it wireless—is becoming mandatory for most medical devices as well as consumer health gadgets. As smartphones and tablets have an undeniable presence in our lives, they provide a readily available, ubiquitous means for displaying and manipulating data. They also push data to the cloud, thereby eliminating the need for custom gateways or hubs of a few years ago. Even the FDA has recognized their applicability and issued guidance around Mobile Medical Apps. Ultimately, interest in connected devices that can interface with mobile platforms—“appcessories,” as they are widely known—has skyrocketed.

Appcessories can be developed in a range of fields—medical, consumer, industrial, and even defense applications. But for companies that have never had to deal with electronics (i.e., pharmaceutical or sporting goods makers), their lack of familiarity with wireless connectivity or the constraints imposed by mobile platforms can pose a significant challenge. Therefore, launching connected devices and apps, maintaining them, servicing future generations, and handling all the data is a huge leap to make. To help those new to the field grasp basics of connected systems design, Cambridge Consultants captured top tips based on our experience in an easy-to-follow guide. Some of those insights are described here.

The first step in developing a connected system (or any product) is deciding what it needs to do and for whom. Identifying a “minimally viable product” is just as important as writing down all the bells and whistles desired. The critical differentiating features that will make your product stand out from the competition are the ones to focus on first to ensure you get noticed in the increasingly crowded market. Next is the development of an intuitive and enjoyable user experience, which is easier said than done but is nevertheless what can make or break market success. User experience is not just about designing the graphics; how users perceive the product, how simple it is for them to incorporate it into their lives, and how they realize the benefit they get from it, all define the experience.

Once you have a feature list, you focus on the engineering. For most connected devices and especially wearable or handheld ones, device size is a stringent target, as is battery life. Both these aspects contribute greatly to the user experience, and despite their inverse relationship, are important to get right. While the electronics (i.e., sensors, microprocessors, memory, etc.) contribute to device size, it is almost always the battery that dictates the required space envelope. As a simple generalization, optimizing device power consumption will yield the longest battery life and hence the smallest battery size. Power consumption is governed by several interrelated factors. You might think that the amount and frequency of wireless data transfer consumes most power, but parts like LEDs can actually drain the battery more. Similarly, maintaining an established wireless connection with the smartphone is more power efficient than trying to make a new one. Thus, turning the radio off may not save power unless the interval between data transfers is very long. Another factor that governs size is the antenna and its requirements, which affect the wireless transmission range, latency, and reliability. The complexity of the antenna and size of the ground plane it requires is dependent on the use scenarios for data transmission. For example, will the smartphone be on a bedside table or in the user’s pocket when data needs to be transferred? Knowing what to optimize is a challenge in itself.

Next, it’s time to think about data—how much is being acquired, how much needs to be stored on the device, and how much must be transferred to the smartphone. The value proposition of a product is in the information it provides, not just the data it collects. Thus, the algorithms that turn data into meaningful, actionable information deserve considerable thought. Trade-offs may be required to decide whether the data crunching should happen on-board or off (in the app or on the back-end). Devices such as heart-rate monitors make a large number of measurements that get converted into beats per minute (BPM). Processing required for this is typically done on-board. But when BPM is used to determine heart-rate variability or stress levels, the decision of where to implement those complex algorithms becomes more significant and depends on the computational power and amount of historical data required. A trade-off must be made between power consumption for wireless transfer of a large data set versus processor cycles and memory writes for on-board processing. The expertise and effort required to implement powerful algorithms on low-power, low-cost microcontrollers found in appcessories should not be underestimated. But if it is essential to implement the algorithm on the device to realize the desired user experience, it makes sense to invest in optimal implementation to prevent killing the power budget and ruining other design must-haves.

With increasingly sophisticated sensors being integrated into smartphones, a move away from dedicated devices is happening in some cases where the data can be collected passively via the phone. Activity tracking is a great example and we are seeing evidence of this in the recent announcement from Jawbone, which will stop making its popular wrist-worn tracker (Up) and instead launched an integrated tracking app for the Apple HealthKit. Samsung has incorporated a heart-rate sensor in the new Galaxy S5 phones and obtained FDA approval for the sHealth software platform. But don’t expect to see them qualifying their phones to provide clinical-grade data heart rate or ECG data. Thus, the smartphone is not about to replace all custom devices, but the amount of integration feasible on that platform is something to bear in mind when building a new measurement-based solution.

Independent of device design, market success is often determined by the service offered and the business model. A move toward service-oriented businesses that are “giving away” the device in order to lock in a sustained revenue stream is already visible. This is especially true in consumer markets and while the healthcare space has its own constraints with respect to reimbursement, contracted purchasing, etc., the recent changes with ACOs and bundled payment models is likely to change how medical devices are viewed. The Quantified Self movement is likely to have an impact in the healthcare space and as people become active participants in their care, the need for appcessories will be even greater. Therefore, when launching a new product, consider the current environment as well as likely future trends to determine path to market. Whether you enter the market with just a product play or an integrated service offering will depend on the particular product, any precedent set by competitive offers, and, most importantly, your ambition as a company.

In summary, the market for connected devices is heating up and will continue to thrive for years to come. Your success in this fiercely competitive space will depend on your ability to convince users that your product/ service has something to offer them—a feat that can be achieved only via the right combination of design, analytics, and business model.