Patents
Determine steps based on accelerometer signals was relatively easy, but determining the speed proved much more challenging, especially on an indoor treadmill with no GPS. The basic premise was that based on the user’s height each step would result in a certain distance being covered. As the step frequency increases the assumption was that the users speed would increase, but the variability in users running patterns made these simple equations error prone. The idea here was to keep track of the step frequencies that the user went through and at the end of the run, have the user enter the distance reported by the treadmill. Then add a proportional adjustment to each step frequency and use this correction in future runs. As the user kept running these adjustments would continue to get more accurate.
Interestingly during the algorithm development and tuning I had a treadmill right next to my cube. We used to change the code and run. I don’t think I was ever as fit as I was while working on this project.
The wearable device had GPS technology which was to be used to determine the speed of the user running with it. The assumption was that the GPS speed would be fairly accurate. However what we found was the GPS speed values change quite drastically especially when running in urban canyons or under thick foliage. So we designed a system that relied on the speed estimated by the accelerometer based step counter and use that to compensate for the variability reported by GPS.
In 2011-12, our small group within Motorola Mobility worked on a fitness device called Moto ACTV. Preserving battery life on this small device was critical so the display was kept off most of the time. To turn the display on, and to prevent the display from turning on by mistake, we came up with a wiggling motion that the user had to perform explicitly. Although this worked well for us, and was eventually deployed in the product, it was not very user friendly. What constituted a proper wiggle was confusing to most users and to the folks writing the user manual. Nowadays in smart watches the orientation of the watches display and the motion to get there is used to determine this.
While working on pagers in the nineties I had several attempted patent submissions but this is the only one that made the grade. The idea was to embed an audio code in the text message sent to the pager, and the pager would interpret it and play the corresponding audio alert or message. I believe the lawyers worked on expanding the scope to be much broader.