What Are Your Wireless Options for Wearable Devices?

This is Part 3 of our series, “The Future of Medical Technology: Wearable Devices.” Read the introduction to wearable devices and how to draft design specs for your device here.

As smart phones become more prevalent, they become the benchmark for user interfaces with other devices — including medical and health tech wearable devices. Everyone now expects to be able to connect to the internet or at least connect a device to their phone. Today, we can connect headphones wirelessly to our music players, synchronize a watch with a cloud service, and upload data from a heart rate monitor to a smart phone.

All these applications rely on some form of wireless communication. Wireless communication may be roughly broken up into three categories based on their range and the amount of data they can handle. Wi-Fi typically represents the longest range and the highest data rates. Bluetooth is a mid range and mid data rate system. Short-range solutions are represented by Radio Frequency Identification (RFID) and Near Field Communications (NFC). Each of these systems has advantages and disadvantages when being considered for wearable devices.

WiFi

When people think of internet connectivity, they are usually referring to Wi-Fi. It offers the highest security levels, the highest data rates, and the longest operating range of these technologies. These advantages come at a cost. The larger range comes at the expense of requiring higher power transmitters, which can adversely affect battery size and life. Wi-Fi antennas are optimized for the expected operating range. These antennas may be as small as 2mm x 5mm for very short operating ranges or may be antennas that are tens of centimeters long for longer ranges. Wi-Fi solutions are generally the most complex of the group and often require external host controllers along with a dedicated radio controller to provide the device functionality. Complete modules are available as certified devices with FCC approvals. Examples of devices that might use Wi-Fi include wearable video cameras that upload high definition video or video headset glasses that download high definition video.

Bluetooth

If a device needs to connect to a smart phone, Bluetooth is the most popular way to go.
Devices that use Bluetooth include wireless headsets, keyboards and mice, speakers and hands-free operation in most new cars. Integrated system-on-chip devices are available from several vendors. These incorporate a microprocessor, memory, power management and radios into a single package. Most devices offer development systems in which the functions of the device may be incorporated into the system-on-chip. This minimizes the total number of chips needed to provide a complete wireless solution. As with Wi-Fi, these modules are available as certified devices with FCC approvals easing overall system integration.

Bluetooth Low Energy (BLE) is a special form of Bluetooth. BLE allows the transmitters to remain in the idle mode for longer periods, thus using significantly less power over time, allowing for smaller batteries or longer run times. Antennas for Bluetooth can be as small as 2mm x 5mm. A typical system-on-chip solution may be four to six times smaller than a Wi-Fi solution. Costs for a Bluetooth solution also tend to run between four to six times less WiFi solutions. Examples of wearable devices that might use Bluetooth include a wrist bracelet body monitor, an audio headset, or an insulin pump.

RFID/NFC

Today, Radio Frequency Identification (RFID) is typically used in inventory control tags, implantable pet ID tags, and access control systems. For RFID, the operating range of these devices is dependent on the antenna size. Larger antennas, on the order of several centimeters in diameter, can yield operating ranges of up to 100 meters. Near Field Communication (NFC) is a specialized subset of Radio Frequency Identification (RFID). NFC is gaining popularity as a means to implement electronic wallets. In order to enhance security, NFC limits its operating range to 10 cm. RFID technology is more mature than NFC, but it is not available in typical smart phones.

NFC and RFID chips are available to provide all the radio functions as well as the processing needed to decode the signals in wearable technology devices. Some systems provide the development environment to allow host functions to be performed by the chip. These chips are comparable in size to Bluetooth chips, however, the antenna size often makes the overall system size significantly larger. Cost is comparable to Bluetooth systems.

Selecting the proper technology to meet your wearable devices’ needs may be a daunting task. If you need assistance in this area, contact Anuva! Our years of expertise in designing and manufacturing medical devices can help transform your idea into a reality!

By Anuva