I could never find information readily available on how sleep actigraphy actually works, but nearly each time someone sees me wearing the Jawbone UP it inevitably becomes a conversation topic and “witchcraft” doesn’t cut it. So after reading a few medical papers (thanks Stanford Library), here’s what I’ve distilled:
What the devil is actigraphy?
Actigraphy is the use of accelerometers (motion trackers) to monitor physical activity, whether waking life or sleep. Pilots, medical professionals, and militaries have used it extensively for decades, and in more recent years increasing numbers of consumer products have been released. The most simple example is a pedometer, and more complex devices include the WakeMate, FitBit, and Jawbone UP. Even some apps will turn your Smartphone into an actigraphy device.
Use of actigraphy for sleep seeded in the 1960s when predictable limb activity was discovered during sleep studies. It was found that wearing an actigraphic device on a person’s non-dominant wrist was actually just about as accurate as more disruptive forms of tracking sleep such as attaching electrodes to your skull. But how is that possible? What is your wrist up to that allows a relatively simple gadget to match the accuracy of machines that measure your brainwaves? Continued…
The 2nd generation Apple TV is selling faster than imagined and offers features seemingly impossible for the 1st gen ATV, but with a minimal ~$50 investment and some simple hacks you can turn Apple’s old “hobby” into something quite special: a HDTV appliance running XBMC (and Boxee). Note that Netflix streaming is technologically possible, but not available at the time of this post.
To be more specific: out of the box Apple TV only decodes H264 video and has some really old hardware, however by replacing the Wifi card with a brand-new 1-watt hardware decoder called the “Broadcom Crystal HD” you can start playing very high quality video for other codecs such as DivX, Xvid, WMV, and so on. As for a video library, personally I’ve opted to stream video from a NAS in my house, but others have upgraded the internal hard drive on the Apple TV to hold more videos.
For this project you’ll need:
- 1st Gen Apple TV (40GB or 160GB)
- Torx T8 and T10 screwdrivers (to install Crystal HD)
- Broadcom Crystal HD BCM970015 (~$50)
- Non-wifi connectivity for your Apple TV (we’re replacing the wifi card)
- About 45-90 minutes depending on your comfort level
One of my favorite photographers on one of my favorite photographic subjects: the tremendously elusive (thank god) nuclear fission reaction. I’ve seen various shots on cobwebsites, but to my knowledge nobody has collected them in one place. (If anyone has more or higher quality images please comment.)
These impossible sights were captured by “Doc” Edgerton in 1952 at a distance of 7 miles (11.2km) using his recently invented rapatronic camera. He was an electrical engineer from MIT turned photographer and utilized an interesting technique to avoid slow mechanical parts in a shutter. Edgerton co-founded EG&G based on his work and it currently employs 11,000 for NASA and US defense contracts.
The first photo is approximately 1 millisecond after detonation while the blast diameter was 20m. The exposures are (ostensibly) 1,000,000,000/sec., or 10ns. In the later photos you can see rope effect; effectively vaporization of material traveling down the cables and trellising. Unlike modern high-speed photography only one shot could be taken per camera and Doc set up 10 cameras for this blast. I’m missing six photos…
I picked up an Arduino recently after about two years of lusting for one — just never had time. The standard first program sketch is a blinking LED (see this great Make Magazine video), but the same time I ordered the Arduino I also bought a $10 (shipped from China) 24×16 LED Matrix from Sure Electronics on eBay. So since more is better, of course I want to make all 384LEDs blink (at random).
With the advent of Amazon S3 and its remarkably cheap storage costs, creating services based on scalable storage has never been so easy and inexpensive as it is today. One area where this is most apparent is the boom of network backup products. In years past, companies like Iron Mountain or EMC would have to create their own million-dollar server infrastructures to support client data. Now a days, you don’t need to pay for anything until you’ve collected payments from clients.
I’ve been playing around with this new web app called timetoast. In essence, it allows you to create and edit flash-based timelines with pictures. It’s relatively simplistic at the moment, but I’m excited to see this sort of product in existence.
I suspect they are planning collaborative features, but currently its single-user creations. A timetoast “wiki” of sorts would be fantastic.
There wasn’t a timetoast timeline for the iPhone, so I filled in the gap.
Let’s take a brief look at what I would call the bottom-line total cost of ownership (TCO) of the original 8GB iPhone versus the forthcoming 8GB iPhone 3G. That is, the TCO of each iPhone with equal data (unlimited), voice (450 min), and SMS text messaging (200 txts).
(Above I’ve charted the initial cost of the iPhone + setup fees + monthly service over 2 years, including taxes and fees. I’ve added a $5/mo text plan and calculated the totals using California sales tax (8.25%) – so the bottom line in different states may be slightly more or less.)
More after the jump, plus another chart of TCO without a text plan… Continued…
Immediately following the 3G iPhone announcement at 11:45a PST this morning, AT&T posted up a press release outlining all the great things Apple is doing for them. Oh, and they also snuck in a $10 increase for the unlimited iPhone data plan. The data price will be $30 instead of the current $20, plus voice. In essence, $69.95 and up for an iPhone plan. Add $10 more if you want a text plan. From AT&T:
• With a two-year contract, the price of an 8GB iPhone 3G will be $199; the 16GB model will be priced at $299.
• Unlimited iPhone 3G data plans for consumers will be available for $30 a month, in addition to voice plans starting at $39.99 a month.
• Unlimited 3G data plans for business users will be available for $45 a month, in addition to a voice plan.
I want to take a couple of minutes and talk about how compelling the Intel Atom platform is for home servers. There has been lots of buzz around the Atom for the past few months since it’s a very low-cost, uber-power-efficient processor. The Atom can be likened to a vintage Volkswagen Beetle: low-cost and low-power and it will still get you to 65MPH on the freeway, but you wouldn’t really want to use it for anything other than to “get from point A to point B”.
Similarly, the Atom meets the basic computing requirements of average users but not much more. This means you can check email, browse the web, use Office but can’t utilize advanced HD video, 3D games, and so forth.
It’s always difficult to try to gather accurate statistical data on operating system market share in the public sector. However, while Stanford University users can purchase any computer they want, they have to report their computer and OS into a database in order to access the Internet from Stanford campus. By looking at that data, tracking market share has never been so easy…
Actigraphy is the use of accelerometers (motion trackers) to monitor physical activity, whether waking life or sleep. Pilots, medical professionals, and militaries have used it extensively for decades, and in more recent years increasing numbers of consumer products have been released. The most simple example is a pedometer, and more complex devices include the WakeMate, FitBit, and Jawbone UP. Even some apps will turn your Smartphone into an actigraphy device.
Immediately following the 3G iPhone announcement at 11:45a PST this morning, AT&T posted up a 
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