标签: Fitbit

  最近看过《疯狂动物城》的朋友想必会对“闪电先生”留下了深刻印象。那种淡定得不知什么叫着急的生活态度，不是能学的来的，当您看着着急，心跳加快的时候，不知人家的心率会是多少。而且，“淡定”，也并不意味着人家就不可以玩儿急速飞车。     假如您也每天都从事着像“闪电先生”一样的办公室工作，每天一坐就是很长时间，不妨自己测测您此时的心率，看看长时间静止不动时的心跳次数是多少？在工间操时间，不知有多少人会按时放下手里的事情，站起来锻炼一下，活动一下身体。每周，您会参加一些像打球，跑步，登山之类的比较剧烈的体育活动吗？在这些剧烈活动当中，不知您的“实时心率”有多快？每个人的“最大心率”按业界的说法是按220减去您的实际年龄作为参考。   久坐不动，对健康不利；盲目的剧烈运动，对健康也同样可能会产生不利的影响。锻炼身体要讲究科学性，国外医学界根据不同的锻炼强度和效果，把心率分成几个不同的区间，比如在高强度锻炼时候的“峰值区间”，“有氧活动区间”，“燃烧脂肪区间”等。根据实时的心率可以很好地了解并控制运动量，但是如何能得知运动期间的实时的心率？这个可能很不好测，停下来，自己按着脉搏数数？好像很不方便。   专业的运动商品店“迪卡侬”有售心率计，使用的时候需要把带有传感器的带子绑在胸部，测量数据会通过无线传输并显示在手上的手表上，还可以设置心率报警门限，达到一定的心率值会发出报警提醒。这类产品据说采用的是电脉冲测量法，通过峰值检测得到心率，这是最准确的一种测量心率的方式。在国外已经被健身爱好者普遍使用。只是这种需要绑在胸部的测量方法可能会让使用者感觉不太舒服，不太方便。   “智能穿戴”是近些年来的热门产品，国内外很多公司都研发并推出了很多价位从两位数字到四位数字人民币不等的产品，品牌众多。总结一下，大概可以分成三类：第一类是功能比较简单的运动手环，能计步，看看时间，监测睡眠，可以给自己设定每天要走的步数，督促自己完成每天的任务；第二类是功能比较全面的运动手环，除了能计步，还能监测实时心率，监测睡眠等；第三类是智能手表，功能就更多了，不一一列举。   出于对“科学锻炼”的好奇，最近开始尝试使用带有实时心率监测功能的Fitbit Charge HR 智能手环。首先，想搞清楚它能监测心率的实现方法。看相关介绍，目前在穿戴设备上普遍采用了一种叫做“光电容积图”（PPG）的心率测量技术，它是利用血液对绿光的吸收性，通过测量反射光强的变化来反映血流量的变化，通过计算从而得到对应的心率数据。目前，大部分的腕带式心率测量设备都采用了该测量方式。   这款手环采用了光电心率传感器，在它的背面，可以看到能发出绿光的两个发光二极管，动一动，就会立即闪烁，中间是一个感光器件，LED发出的双光束照到皮肤上，当心脏收缩时，外周血容量最多，绿光吸收量也最大 ，检测到的反射光强度最小；而在心脏舒张时，反射光强度最大，再把这些光信号转化成电信号后，计算出心率数据。戴上它就可以一直都在追踪你的心率变化并显示出来。另外，它还内置了加速度计和气压计量，可以记录步数、心率、攀爬的高度和运动强度(散步或跑步)。 图1：带心率监测的Fitbit Charge HR智能手环   貌似功能不少，来段“登山运动”，实际感受一下在不同情况下的监测结果如何！早晨，从香山脚下的停车场开始徒步上山，身体需要预热，不要着急，控制好速度，路过麦当劳和许多驴友喜欢约见的集合地邮局门口，此时看看这段时间内心率的变化，如图2所示，最高没超过每分钟128次，介于79到128次之间，按软件指示，主要属于“脂肪燃烧”的范围，看来把心率控制好在这个区间，可以很好地减肥呦。   图2：预热阶段的心率监测结果   穿过一片零散的村落，抬头望去可以隐约看见山上沿着“好汉坡”的路线登山的队伍。这是条“野山路”，没有人工修筑的台阶路，登山过程中，感觉心跳逐步加快，自己下意识地时不时敲击一些手环，看看屏幕上显示的当前心率，提醒自己控制好速度，不要使心率太高。经过十几分钟的攀爬，跟手机同步一下数据，看看这段登山过程中心率的变化，统计结果如图3所示，看到心率明显呈上升趋势，最高没有超过155次，一年没登山，发动机稍显吃力，大部分时间属于“心肺锻炼”范围，有4分钟属于峰值锻炼区域。   图3：登山阶段的心率监测结果   到达山顶之后没有停歇，继续下山的行程。下山感觉要轻松多了，借助登山杖，貌似可以一路小跑。过了一段时间，同步一下监测的数据，看到如图4所示的心率变化，介于79到128次之间，属于“脂肪燃烧”的范围，适合减肥。   图4：下山阶段的心率监测结果       今天的运动量应该不小，同步一下，看看数据统计，如图5所示。   图5：一天的运动量统计     第二天收到一条通知，提示“电量不足，请尽快充电”。这款手环号称“普通情况下电池最多可使用5天”，我是经常开着蓝牙进行数据同步，大概能工作3天。既然该充电了，我也顺便微测一下它的充电情况。内置的电池容量不会大，测测充电电流有多大。接到一台数字万用表，开始充电测试，此时测到的充电电流是59.6mA，真不大，如图6所示。   图6：手环充电电流测试   改用数据采集和图形显示的方式测测充电过程，在“较高采样率”情况下采到的充电电流的波形有比较大的波动，如图7所示。   图7：手环充电电流的波形   把采样率降低，进行长时间的捕获，看到如图8所示的充电电流的波形：经过了大概20分钟的平坦的恒流充电之后，充电电流开始逐步下降，到了大概34分钟的时候充电电流从大概60mA降到了22.4mA。   图8：充电电流的变化波形   一共充电了大概43分钟之后，看到充电电流不断地逐步降低，此时变成了13.2mA，如图9所示，基本上可以认为充满了。   图9：充电电流逐步降低   也许有人怀疑佩戴智能手环会不会对人体有电磁辐射？手环内部的电路不应该会产生多大的电磁辐射，如果有，主要会来自蓝牙的通讯，但，发射功率不该大。定性地实测一下，如图10所示，打开手机的蓝牙，与手环进行数据同步，粉色轨迹为通讯前的背景频谱，黄色轨迹为蓝牙通讯期间捕获到的信号频谱，通过标尺测出功率为-42.78dBm。   图10：蓝牙通讯信号的功率测试   如果说“兔子爱吃胡萝卜”完全是动画片里杜撰出来的，那么本文从淡定的“闪电先生”说到了心率，说到了心率监测，说到了智能手环，最后又扯到了手环的微测，这样的故事情节很有可能是刚看的这部动画大片所导致的。 注： 1. 若转载到其他媒体，请注明出处： EDNChina JIGONG 的博客 微测 2.我的EDNChina 微测 的所有博客文章： http://bbs.ednchina.com/blog_index.jspa?blog_id=2004572

People are now interested in tracking their health as proven by the success of the Nike FuelBand and Fitbit. In fact, a recent survey suggests that 75% of Americans believe that wearables will positively impact their health. While activity trackers may be good for your waist, they can kill the perfect outfit. Wellograph , a stylish wellness watch, wants to correct this.     Wellograph wants to create an activity tracker that you will want to wear proudly to an important business meeting or a first date. And it's doing this with a keen eye for design and the selection of the right materials.   Wellograph president Nick Warnock told Designers of Things that the current design presented at CES this past year was a result of 15 to 20 iterations. He believes that Wellograph stands out from what is becoming a crowded wearable health space because the Wellograph is a stylish piece of jewelry and not “a piece of plastic you wear on your wrist, arm, or head.”   The Wellograph wellness watch is the first wearable to be made with sapphire crystal. This material is stronger than steel and can only be scratched by diamonds. Warnock believes the smartphone industry will shift to sapphire crystal, citing the recent news of Apple’s sapphire crystal plant in Arizona.   Unlike other activity trackers that just track activity, Wellograph monitors your heart rate, which means that it has the ability to calculate calories burned and measure your aerobic fitness. For Warnock this means that Wellograph better measures your complete health rather than just steps.   But the target audience for the wellness watch is not the pro athlete. Warnock explained that he expects Wellograph on the wrists of the working professional who wants to keep tabs on his health while wearing an accessory for status or to add to his sense of style.   The Wellograph works independent of a smartphone. It can store up to four months of data, and all of the data collection and visualizations do not required a connection. But Wellograph will be launching companion apps for iOS, Android, and Windows 8.1 smartphones, which will let users store and dig deeper into the metrics gathered by the watch.   Wellograph is currently accepting pre-orders for its device for Rs.21,151.52 ($349). It comes in black chrome and silver satin. The company is making only 10,000 available in its first run.

Here's another column in which we pause for a moment to take a deep breath (hold it... hold it... now exhale), slow down, relax, and start winding down in preparation for the weekend. As part of this exercise, I've gathered a few choice diversions for your delectation, delight, pondering, and rumination. This week's humble offerings are as follows: No. 1: Let's start with something related to the use of light. My chum with the screen name Antedeluvian (yes, he knows it's the wrong spelling) sent me a link to the most amazing video showing projection mapping onto flat surfaces. The illusion is incredible. You have to keep on reminding yourself that these are just simple flat surfaces you are watching. ( Click here to discover more.) No. 2: Speaking of light and the manipulation thereof, my friend Jay sent me a link to a rather interesting article about a building that has cameras pointing in all directions. The images from the cameras on each side are processed and presented on display panels on the complementary faces. The end result is for the building to appear to be invisible. Hang on, maybe there isn't a building there at all? ( Click here to discover more.) No. 3: Still on the subject of light, I'm sure we all know that photons are massless elementary particles that don't interact with each other and that act as the force carrier for the electromagnetic force. Wait just a minute—did I say massless and don't interact with each other ? Well, it seems that scientists have been able to coerce photons to interact with each other to the extent that they form "photonic molecules" that appear to have mass. I'm still trying to wrap my poor befuddled brain around this one. ( Click here to discover more.) No. 4: I recently wrote a blog about the Fitbit Zip, which counts how many steps you take throughout the day. In a response to this blog, a reader basically called me an idiot (well, I took it that way). Happily, I refuted Truthfinder's assertion as to my mental capabilities in this follow-up blog . I must admit that I was feeling a tad perky when I finished this blog. It reminded me of the French Taunting scene in Monty Python and the Holy Grail, when the Frenchman on the castle ramparts shouts, "Now go away or I shall taunt you a second time!" ( Click here to see this scene.) No. 5: Of course, this immediately reminded me of two classic videos in which the dialogue from Monty Python and the Holy Grail is dubbed over a collage of scenes from the original Star Trek on its "five year mission behind the beyond, behind which no man has gone behind, beyond, before!" LOL. ( Click here and click here to see these compilations.) No. 6: Last but not least for this week, I just saw a rather funny video of Bill Bailey performing the Hokey Cokey in the style of Kraftwerk ( Click here to see this video.) As usual, if you know of any interesting sites you'd care to share, please share them in the comments section.  

As I said in my previous blog , my new Fitbit Zip is proving to be an amazing motivator when it comes to exercising. I now find myself going out of my way to walk a few more steps, just to see them reflected on my personal online dashboard. Having said this, there are a few considerations of which users should be aware... First let us remind ourselves that there are three members of the Fitbit Family, as follows: * Fitbit Flex: Wireless Activity + Sleep Wristband * Fitbit One: Wireless Activity + Sleep Tracker * Fitbit Zip: Wireless Activity Tracker Each is worn and used in a different way. I have the Fitbit Zip as shown below. This comes with a clip (not shown in this image) that allows you to attach your Fitbit just about anywhere on your person.   As an aside, I would like to note that the Fitbit's clip is a wonder of modern materials technology and engineering. It really grips your clothing, making it practically impossible for you to lose your Fitbit, even if you are running at high speed. Now, before we proceed to the main thrust of this blog, I must say that I was a little surprised to get the following feedback: You were walking on the treadmill while writing your post and the Fitbit on your wrist. So your arm was not moving/swinging with every step you were taking? And you expect the Fitbit to record your step without your arm swinging? What nonsense is that? The Fitbit and every other similar arm/wrist band pedometer that pretends to count your step while sitting on your arm is making fools of consumers like you. And once the step count is wrong, every other information such an instrument gives out is wrong. Did this never occur to you? Well, someone certainly got out of the wrong site of the bed this morning, didn't they? Having said this, after re-reading the above comment a few times, I'm beginning to wonder if the poster's antagonistic and resentful tone is based on the fact that he or she spent some time walking on a treadmill while wearing an armband activity recorder without swinging his or her arm, and that he or she is still disgruntled by the fact that those steps weren't counted towards that day's total (LOL). I replied to the poster saying: "Did I say the Fitbit was on my wrist? (No) Do I look like an idiot? (Don't answer that :-)" The thing is that "I R an engineer," so the potential for these problems had—of course—occurred to me. This is why I had already investigated the situation as described below. The first thing that struck me when I donned my Fitbit Zip was that you wear this little beauty throughout the day and there's no way to turn it on and off. The reason this was of interest to me is that my ride home involves a bumpy road that seems to breed potholes, so I wondered if driving in my truck would trick my Fitbit into thinking I was walking or running. All I can say is that there is some serious DSP (digital signal processing) taking place. I checked the step count before I set off and again when I arrived home. After travelling more than 10 miles over a very boisterous route in the "bumps department," my Fitbit Zip had only incremented its count by two steps. Personally, I think this is little short of miraculous. The next morning when I came into work, I decided to try a few things. My typical garb in the summer is shorts, sandals, and a Hawaiian shirt. My leather sandals tend to flap around a bit, much like flip flops. Keeping this picture in mind, I noted the current step count and then started to walk around my office building with the Fitbit clipped to my shirt's breast pocket. I counted 100 steps and then stopped and checked the count against my Fitbit. Sad to relate, there was a noticeable error. I then repeated the experiment with the Fitbit attached to different parts of my body (well, to different parts of my clothing) as illustrated below:   I might note that all this took a lot longer than you might expect. I didn't have a piece of paper or a pen with me, so I was doing it all in my head (which is why I don't recall the exact values). Also, I'm easily distracted, so I'd see something interesting and lose my count, or I'd stop at 100 steps and realise I couldn't recall the starting value. I'm sure the other folks in the building (a) got tired of seeing me walking past their windows and (b) wondered what the heck I was doing. The bottom line is that in each case (Fitbit clipped to shirt pocket, short centre, trousers side picket, and trousers centre), there was some amount of error in the step count. I found this to be a little disquieting. I'm a bit of an obsessive compulsive when it comes to things like this. You can call me old-fashioned if you will, but I do like my numbers to add up to the correct value. Of course, most folks don't perform serious training in flip flops, so my next step (no pun intended) was to exchange my sandals for socks and sneakers and to repeat the experiment. In this case, I'm delighted to say that my Fitbit Zip was pretty much 100 per cent accurate irrespective of the location to which it was attached—I don't think it ever miscounted by more than one step per test. Now, this is where things get interesting, because I then repeated the entire suite of tests while walking on the desk treadmill in my office. What do you suppose I saw? I have to admit that I wonder if Truthfinder is reading this column. I still hear (in a metaphorical sense, of course) his or her words ringing in my ears: "Did this never occur to you?" I must admit to feeling a tad miffed by this; perhaps even a mite peeved, if you will pardon my language. (See also England raises threat level from "Miffed" to "Peeved" ) So, just to remind ourselves, the following tests were performed on the desk treadmill in my office. This treadmill is very accurate when it comes to counting one's steps. The great thing is that I can watch it counting as I walk, so I have 100 per cent confidence in the values reported by the treadmill. Once again, as reflected in the image below, I performed the tests with the Fitbit clipped to four locations: my shirt pocket, the middle of my shirt, my trousers side pocket, and the middle of my trousers. The reason for the different amounts of time (number of steps on the treadmill) for each test is that I had to keep on stopping to answer the phone.   I calculated the delta percentage error in the step count using the absolute value of the treadmill count (which we know to be correct) minus the Fitbit's count, all divided by the Fitbit's count and then multiplied by 100. Now, remember that all four Fitbit-attachment locations reported accurate values when I was walking around the car park on a solid (asphalt) surface. In some cases, however, walking on the treadmill causes the Fitbit to "throw a wobbly" as it were. The worst-case scenario occurs when the Fitbit is clipped to one's shirt pocket (a whopping 55.57 per cent error). The best-case scenario is when the Fitbit is clipped to the centre of one's trousers (a miniscule 0.1 per cent error). Personally, I am more than happy with a 2-step (0.1 per cent) error out of 1,936 steps. I can live with that. I should, however, note one last point, which is that all of my tests were performed while walking—it may well be that the picture changes when one is jogging or running. Consider the first test shown above in which the Fitbit was attached to my shirt pocket. While walking on the treadmill, the Fitbit reported far fewer steps than I actually took. It may be that, if one were jogging—which can cause a Fitbit attached to one's shirt pocket to bounce up and down a few times—the Fitbit might end up reporting substantially more steps than one had taken. But since I am not a big fan of jogging (you have to look after your knees), I'll leave that experiment to someone else. If you decide to perform that experiment yourself, please share the results with the rest of us. Well, I think that will do for now. Please comment below if you have any questions or thoughts (preferably on the topic of wearable electronics, but I'm happy to talk about almost any topic—the real trick is to get me to stop talking). Until next time, have a good one!  

My new Fitbit Zip is proving to be a wonderful motivator when it comes to exercising. I now find myself going out of my way to walk a few more steps, just to see them reflected on my personal online dashboard. What can I say? It's great to be me! And why do I say this? Well, apart from the fact that I'm dashingly handsome, a trendsetter, and a leader of fashion (it says so in the introduction to my books, so it must be true), I love gadgets and gizmos, so I'm the luckiest of lucky little rascals because people send me all sorts of goodies to peruse and ponder and play with. For example, do you know about Microchip's recent announcement of the PIC24F 'GC' MCUs With Intelligent Analog? These little scamps boast all sorts of features that make them ideal for a wide variety of portable applications. Well, a couple of days after I'd posted that column, a Fed-Ex package from Microchip landed on my desk. When I opened this package, I discovered something called a Fitbit Zip:   To be honest, I'd never heard of the Fitbit family of wearable electronics before, but if you bounce over to the Fitbit Store , you will discover that they currently have three products: * Fitbit Flex: Wireless Activity + Sleep Wristband * Fitbit One: Wireless Activity + Sleep Tracker * Fitbit Zip: Wireless Activity Tracker Well, I must admit that I was intrigued. When I opened the Fitbit Zip package I discovered the teeny-weeny Fitbit Zip itself, which is shown here next to a quarter:   This was accompanied by a replaceable battery that is said to last anywhere from four to six months, a moulded plastic clip by which you attach the Fitbit Zip to your person, the smallest wireless USB dongle I've ever seen in my life (to plug into your PC or Mac), and a strange piece of plastic whose function was a complete mystery to me. The instructions accompanying this little rascal couldn't be simpler. They say "To set up, go to: www.fitbit.com/zip" (in multiple languages). When you go to this site, you see three simple pictograms—the first shows you inserting the battery; the second shows you plugging the wireless dongle into your computer, and the last shows you clicking a button (which you do actually click on the pictogram) to download and install the software driver onto your computer. First came the battery. There is a groove in the back cover to the Fitbit Zip. I had to borrow a penny from Bob in the office next to mine to use as a sort of screwdriver in order to open the back, insert the battery, and close it up again. A few seconds after I'd done all this, I noticed another graphic on the screen showing "What's included in your Zip box"—it turned out that the mysterious plastic "thing" was in fact the "Battery Tool" that you use to open and close the cover (give me strength!). Next came the wireless dongle, which was followed by the software download. As soon as the software is downloaded it broadcasts a wireless message (presumably to any and all Fitbits in close proximity) telling them to display the (relatively) unique 4-digit numerical codes associated with them. Then it tells you to look at the code being displayed on your Fitbit's screen and enter that code into your computer. This way, if multiple folks in close proximity each have their own Fitbit, everyone (computers and Fitbits) knows "who is who." Also, as part of this initialisation, your computer uploads the local time into your Fitbit. This provides a great illustration of just how simple the entire process is. Last but not least, you use the supplied plastic clip to attach the Fitbit Zip to your person, and then you are up and running (or walking, as the case might be). Thereafter, the Fitbit keeps track of every step you take. Once every 20 minutes or so it synchronises itself with your PC. If your PC is turned off or is out of range, your Fitbit will just try again 20 minutes later. Whenever you feel like doing so, you tap the screen of your Fitbit to cycle through a series of displays showing things like the number of steps you've taken thus far this day (the goal is 10,000 steps each day), the number of calories you've burned, and so forth. You can also bounce over to the Fitbit website to see your own personal dashboard showing all of this information as illustrated below:   The above image shows only my daily values. You can also see your cumulative totals along with a bunch of other information. Also, as another illustration as to how simple everything is, your Fitbit resets itself back to zero at midnight without you having to do anything at all. (Don't worry, it will still remember any unsynchronised values from the previous day(s) and upload them to your PC the next time they link up.) There are also lots of other cool features, like the ability to form/join groups with other users and then compete against each other. My Fitbit Zip has proved to be a real motivator to me. I'm once again using the Treadmill Desk in my office every day while performing tasks like answering emails and taking part in online chats. I'm also parking my truck further away from things like supermarkets and malls so as to get a few more steps towards my daily total. Yesterday, for example, while changing planes at Dallas airport, I walked all the way from Gate 37 at the far end of Terminal D to Gate 9 at the far end of Terminal A (this is not a short walk). I actually ended up getting more exercise than I expected, because when I finally reached Gate 9 in Terminal A, I discovered that there had been a gate change and my flight was now departing from Gate 38 in Terminal A—I gate I'd walked past quite some time ago. "Oh dear," I said to myself (or words to that effect). In conclusion, I have to say that I'm very, very impressed. This is such a simple concept, but it's certainly got me doing significantly more exercise (in the form of walking) than I was doing before. The main thing for me is that it's so easy to use. All I have to do is make sure I'm wearing it—I don't even have to turn it on and off. How about you? What motivates you to get out of your chair and do some exercise?