Posted by David Bairstow
Of all the methods available for wirelessly transferring data from one device to another, companies in the wearable industry have chosen Bluetooth as their frequency of choice. Bluetooth chips are inexpensive, and establishing a connection over Bluetooth consumes less battery power than the alternatives. Unfortunately, devices can only access location data over Bluetooth when paired with another device that has GPS, Wi-Fi, or a cellular connection. The good news is that while wearable developers hold onto battery life with white knuckles, they don’t have to sacrifice it for location features.
It’s true that establishing a Wi-Fi connection consumes more device battery life than establishing a Bluetooth connection. How much more depends on innumerable factors like the size of data transfer and applications running simultaneously. However, by adding Wi-Fi chips, wearables - like all mobile phones - can retrieve location by scanning for nearby Wi-Fi networks without ever connecting to one. When using Wi-Fi in this way for location, it is using significantly less power than when using it for data transmission.
Many Bluetooth chips on the market today, including the Broadcom BCM43142, have combined Bluetooth and Wi-Fi capabilities. By using these existing Wi-Fi chips, or by adding an additional low-cost part, wearables can also retrieve location by scanning for nearby Wi-Fi networks without ever connecting to one. Wearables powered by these chips simply need to switch on their already built in Wi-Fi scanners to get location. Compared to using Wi-Fi for data transmission, using it only to do an occasional scan every few minutes contributes a negligible amount to your device’s battery consumption.
Using Wi-Fi scans to surmise location data is a method frequently used by mobile phones, and one that wearables should take advantage of too. If your device has a Bluetooth-only chip, you need to add another chip to use our system, or switch to a combo chip. A combo chip is the best option for size, cost, and power and is less disruptive to the device design in terms of footprint and board space.
To put this into context, a user with a location-enabled fitness band wants to chart her run. When the band is connected overnight, it downloads information about the location based on where the user is. The next day, the user puts on her band and leaves her apartment for a run while keeping her phone at home.
As she runs, her fitness band scans for Wi-Fi networks, matching them with the coordinates pre-loaded into its memory the night before. The user runs 5 miles away from her apartment, beyond the range of pre-loaded Wi-Fi networks. The device then begins to collect data about the Wi-Fi networks it passes. When the user returns home, she pairs her band with her phone over a Bluetooth connection. Her accompanying mobile app displays her run on a map by combining the pre-loaded location data from Wi-Fi hotspots she passed along the way and positioning the out-of-range beacons using Skyhook Optimized Location. Whether or not the data is pre-loaded, or the device is connected, disconnected or intermittently connected, the location of the wearable can be ascertained using Skyhook’s location technology.
The result is a full-color picture of the user’s run: where she went, hills she ran over, scenic views she passed, popular stopping points used by others in her social network. And her device paints that picture with minimal impact on the battery.
Many manufacturers rushed to market early with minimum viable products, valuing speed to market over long term vision. In 2016, we’ll see wearables expand their capabilities and begin to compete on user experience. The winners in the market will make products that users can’t live without, like today’s smartphones. Better user experiences start with the basics like increasing battery life and adding location data.