Pervasive monitoring is one of the visions of my future. When our technology is able to unobtrusively and transparently keep track of us. Where we’ve been, how many calories we burn, what we see, what we do, where we are, the state of our health. Then, be able to distill this information and provide feedback. Privacy concerns aside, I think the information is meaningful and can be applied in interesting ways.
I had this in mind when I ordered a Fitbit. My geeky self looked forward to adding yet another toy to my utility belt.
What this is $100 device? A sensitive accelerometer that measures movement all the time. It beams this information to the mothership in the cloud, which populates their website where you can track this sort of interesting stuff. The logic can derive what you’re doing – walking, running, sleeping, climbing. It measures how active you are and can calcuate the approximate number of calories you’ve burned.
Design and Ease of Use
The Fitbit a couple of inches long and U-shaped to clip to a belt or other bit of clothing. It’s covered with a transclucent rubbery coating that hides a screen, which lights up when you push the single button on it. Some people have complained about breaking it at the clip. I can see this happening – the unit appears to be made entirely of plastic. I can attest from personal experience that belt-mounted items tend to lead hard lives – espeically the clip parts. The Fitibt comes with a holster with another, fatter clip for attachment to thicker items. I think I will be using that most of the time, or dropping it into my pocket. Also included in the package is a soft wristband to hold the Fitbit during sleep. More on that later.
The physical interface features Apple-like simplicity. It logs all the time, no mater what. There is a USB-powered dock that charges the device and also contains the wireless receiver. The Fitbit can be inserted into the dock either forwards or backwards – either orientation works; a clever touch. The battery lasts 3-5 days. So long as the dock is plugged into a computer with the Fitbit software running, the Fitbit continuously syncs with the mothership when it’s within range of the dock – about 15 feet. As with the rest of the core functions, the sync is totally transparent to the user.
Tapping the button on the unit cycles through the different metrics – steps, floors climbed, calories, distance travelled, time. Holding the button starts and stops activity logging, which lets you designate specific periods of activity you want to track. You don’t actually input the type of activity – the device (or website logic) figures it out for you. Except for sleep, you don’t really need to identify activities manually – you can always go to the website and isolate activities you want, by time of day. The metrics reset daily.
It’s attractive and well-designed in both appearance and functionality. I don’t give such accolades lightly.
The website is the primary interface for the Fitbit. There you input your details, height, weight, gender, etc. – the data needed to estimate activity based on the accelerometer motion. You can also tweak the device settings, such as sleep senstivity and whether the screen is oriented for right or left handed use.
The dashboard on the website summaries your daily metrics and activity and you can log other things like food, weight, blood pressure and glucose. It integrates with other fitness tech toys like the Withings scale. It can also feed other social networking and health-related websites such as FourSquare, about.me, Lose It and Microsoft Health Vault.
As is the norm for any modern social media site, the Fitbit website awards motivation badges for various levels of accomoplishment – daily steps taken, floors climbed, total mileage, etc.
Collectively, it gives you a picture of how active and healthy you are.
Aside from motion measurements, the Fitbit measures sleep. To do this, you wear the wristband, housing the Fitbit, on your non-dominant arm. It derives your quality of sleep based on how often you move as you sleep and how quickly you fall asleep. Apart from logging each time I go to the bathrrom, I’m not really sure how accurate it is. It seems to be accurate in measures how quickly I fall alseep (within minutes), although it logs anywhere from 6-12 one-minute periods where I’m awake, but I have no memory of it. Presumably, I’m in a light sleep, moving around, but not entirely awake.
I tested the Fitibt in a variety of activities and compared it to the Garmin Forerunner 405cx GPS, the electronic pedometer on my Sony mp3 player and actual cartographic distances measured using Google Maps.
For walking, the steps counted was very accurate when measured against the mp3 player. To calculate distance, you input your stride length and it multiplies that by the number of steps. As far as I can tell, it doesn’t directly measure later accleration like the Nike+ footpod. There’s also no way to calibrate it over a known distance. Therefore, the accuracy is entirely dependent on the accuracy of your input for your walking stride and how consistent your stride actually is. I measured my walk to work many times, and it was accurate to within 100m over the 1.5km route.
For hiking, the Fitbit counts steps as accurately as walking. Due to the uneven terraing generally encountered while hiking, there will be more variation in stride length, vs. street walking. In a hike of 16.2km, it measured 15.75km. That’s not bad.
The Fitbit appears to severely undercount steps while running. The distances it reports are about 60% of the actual run. The number of strides it measures is low. I can tell because it’s reporting a stride ride of 120-140 steps per minute. I know my stride rate is 183 steps per minute, measured using high-speed video using the Asics Foot ID system. I was quite disappointed it was so inaccurate for runs. I used it on many runs, mounted both on my arm and waist, all with the same results.
It is wildly inaccurate for skating, although I expected that, since it’s not a step-related activity. It looks like it might measure strides correctly, but since there is so much glide during skating, the distances measures are totally inaccurate. The skating motion seems to trigger the climbing metric, as it reports a crazy number of stairs climbed.
In a Nutshell
The Fitbit is ideal for people who are moderately active and using walk-paced activity as a means of fitness. The website can motivate users to maintain and improve their activity level.The primary advantage is it monitors all the time, so long as you remember to wear it, and automatically uploads info to the mothership.
The sleep measurements are very interesting, although the website doesn’t really suggest any corrective action to improve the quality of sleep.
The inaccuracy makes it useless for runners, which is disappointing. Running is something this type of accelerometer-based technology should measure well.
It’s useless for other non-step sports, such as cycling, skating and weight lifting.
- Very nicely designed and easy to use.
- Tiny and unobtrusive.
- Transparent and pervasive monitoring and works automatically.
- Good website and cross-integration with other sites.
- Very accurate for walk-paced activities.
- Interesting sleep measurement function.
- Totally inaccurate for running.
- Does not measure non-step exercise.
- Does not self-calibrate for stride length.
- It’s tiny and unobtrusive. It’s a matter of when, not if, this thing goes into the wash cycle.
I want a wrist-mounted unit that combines:
- The accelerometer and ease of use of the Fitbit.
- GPS for more accurate position and distance mesurement, like Garmin Forerunner.
- Self-calibration to avoid stride length input, like Nike+.
- Vibration alerts and bluetooth integration with my phone, like Jawbone Up.
- Skin-based heart rate monitoring, like Mio, but more accurate and hands-free.
- Non-invasicve glucose measurement (this tech doesn’t exist, as far as I know).
- Weight measurement (I have no idea how this would work).
- Records everything and beam it to the mothership transparently, via celluar data connection.
- Emails me with instructions and feedback on what to do better, and when.
- Tells the time and plays mp3’s (what the heck?).
Much of this tech exists – it’s a matter of mashing them up in a sufficently small and light package to be unobtrusive and with enough battery life to be not-annoying. I can’t wait for the future.