Skip to content

Wrist Actigraphy and Latest Crazes: Fitness Trackers

It started with a report based on How Much Sleep Do Fitbit Users Really Get? A New Study Finds Out by Danielle Kosecki. That lead to research about Wrist actigraphy. And then Amazon had a sale on the Letscom Fitness Tracker. Actigraphy has been around since the 50’s. The cell phone sensor revolution has put it into the realm of every day, every man use.

A fitness tracker is a stripped down cell phone worn on the wrist. Bluetooth is the usual communications method used to pass data to a cell phone app. The sensors are an accelerometer and a pulse meter. A display, battery, and an SOC round out the package. On the Letscom, the accelerometer is  Kionix KX022 and the SOC is a Nordic nRF51822. From a modern hardware perspective, there isn’t much there. It’s the software and the social and cultural aspects that make the product.

First up on software is the device firmware. It needs to track activity and control and present its measures in a reasonable fashion. It also usually provides wrist watch functions and some Smartphone coordination for alarms and messaging.

The second level is the phone app. Letscom uses VeryFitPro (Google Play). Google has been involved in this area and has Google Fit for an API and some other standardization for sharing on social networks and interactions between devices. It is this sharing that Fitbit may be using with cloud storage to collect data from its users that makes data mining research feasible and useful. The app provides extended data storage and analysis for the fitness tracker as well as serving as a larger display and control and configuration device.

Third level software is where the fun starts. That is where you tap into the data flow for doing your own presentation and analysis. This is not directly supported but there are several websites out there about methods to get fitness tracker data to your own database.

The Letscom costs quite a bit less than the market leading FitBit. It seems well built and both the firmware and the app are well rated and quite usable. Even at the normal $30 Amazon price, it offers a lot for the cost, especially as a starting point on how the development of modern sensors can be used for new products and in reducing costs of medical studies or other quality of life interests.

The problem with science is people

This is a book review. The field is medicine but the concepts apply to any ‘fuzzy’ research (including climate change and weather).

Rigor Mortis: What’s Wrong with Medical Science and How to Fix It by Harriet Hall — “Medical research has been plagued by less-than-rigorous practices and a culture that rewards quantity over quality. In a new book, Richard Harris identifies the problems, proposes solutions, and offers hope.”

“Scientific medicine has made great strides, but much of today’s research is unreliable. As Harris says, “Biomedicine’s entire culture is in need of serious repair.” He has done a stellar job of identifying the problems, possible solutions, and promising efforts that are already underway. Research jobs and tenure in academia should be awarded based on quality, not quantity of papers published. Studies must be replicated before they are relied on to direct future research. We need better incentives: today, it pays to be first to publish; it doesn’t pay to be right. We can do better. We are trying to do better.

Anyone who does research or reads about research studies will profit from reading this book. It’s well-written and accessible, with short chapters and lots of entertaining vignettes.

There are some interesting lists about faults found and issues discovered.


Why Modern Computers Struggle to Match the Input Latency of an Apple IIe By Joel Hruska — “The system with the lowest input latency — the amount of time between when you hit a key and that keystroke appears on the computer — is the Apple IIe, at 30ms.”

There is a table of measurements that included latency, clock speed and computer year. It doesn’t include the TRS-80 nor list CPU so you can’t tell how much latency is based on system design or CPU design or other factors. The table does list the number of transistors in the CPU’s under test. “the color coding shows that chips with higher numbers of transistors tend to be in systems with more latency, and faster systems tend to be older than slower ones.”

An Apple IIe isn’t handling sophisticated multi-tasking commands. It isn’t juggling background threads, or dealing with multiple applications that aren’t designed to be aware (or careful) of one another. It isn’t polling a huge array of devices that range from audio and network controllers to discrete GPUs and storage. The Apple IIe OS doesn’t use a compositing window manager, which adds latency. This article, by Pavel Fatin, is an in-depth breakdown on latency processing and discusses how each much delay each step in a modern system adds, from keyboard scan to final output.

Latency is a big issue in movies as well as people notice when the lip sync gets too far off. Typists learn to touch type and that doesn’t involve latency except that the machine can keep up. Virtual reality, gaming, and graphics can make latency critical for error reduction. The real question is how much is OK and how much is too much. Human’s have latency, too, 


N1GNV Christmas Message

John Bee, N1GNV, of Quicksilver Radio Products  sent a Christmas greeting that contains good advice for the Amateur Radio enthusiast and some ideas everyone should think about for making and enjoying happy and prosperous

I just want to take a minute to wish you and yours the very best for the Holiday Season.  May it be filled with the joy and warmth that family and friends bring.  I have many wonderful memories of my own childhood Christmases; many more of them when my children were young; and now we’re making new ones as they have grown into adulthood.  Seeing one’s children grow into happy and productive people is truly one of the best gifts we can receive.  Many of my customers are already Grandparents, and I’m sure that is another source of happiness, especially at this time of year. 

2017 will mark the 15th straight year of growth for Quicksilver Radio.  Without such great customers, this would never have been possible.  It’s always gratifying to hear either in person at a Hamfest, or by e-mail, that you enjoy my newsletters and find useful information on my Web Site.  I truly appreciate your support, and your business.  Having a job that I enjoy in a field that I love is something I’m thankful for every day.

As 2017 slides into 2018, it’s natural to think about plans for the coming year.  And I’d like to ask a favor of you — please put Ham Radio on your list of New Year’s Resolutions.  Here are some ideas to consider:

1.  If, by chance, you are not yet a licensed Ham Radio Operator, get your license this year.  If you have not yet passed your General or Extra test, do it this year.  Having trouble studying or passing?  I have some tips on my Web Site that I think will be helpful.  Click here to see them

2.  Try something.  A good friend of mine likes to say that there are 30 different kinds of Ham Radio, and there’s something there for everyone.  FM repeaters and HF SSB just scratch the surface.  You already have a computer.  New digital and sound card modes seem to appear weekly.  A year ago, no one had heard of FT-8.  It’s now, by many accounts, the most popular HF Digital mode.  D-Star, DMR, and other digital voice modes are growing by leaps and bounds.  Have you tried 6 Meters yet?  The Magic Band can yield some surprising contacts.  How about SSB or CW on 2 Meters or 70 Centimeters?  Every Ham has full privileges on all of the bands above 30 MHz.  Antennas are small and easy to construct from hardware store parts.  It doesn’t have to be pretty — an ugly antenna will radiate just as well.  Use your imagination and try something different! 

3.  Do something.  Set an achievable Ham Radio goal for the year — and then work at it!  Earn DXCC or WAS, maybe on a single band?  Better your contest score by 10%?  Get your CW speed up to 20 WPM?  Reorganize and rewire the shack?  Order a copy of the ARRL Handbook or Antenna Book, and start increasing your technical knowledge?  Convert your paper logs to electronic format and start using Logbook of the World?  One of my father’s favorite sayings was “Whether you think you can or you think you can’t, you’re probably right.”  Just do it!!

4.  Build something.  Too many years ago, as I newly licensed Ham I got very involved in Packet Radio.  With a double throw switch and some mic connectors, I built a box to allow either voice or data use by just flipping the switch.  Not exactly cutting edge, but it worked and led me to build plenty of other handy gadgets over the years.  Simple projects can also be a great way to teach new hams the basics of soldering and kit-building.  String up that antenna you’ve been thinking about forever and see how it plays. Download a free antenna modeling program and learn how to use it to design and build your own BandBlaster.  Order a kit and assemble it.  Melt some solder and have fun!  Once you start you’ll be hooked.

5.  Learn something.  Microcontrollers like the Arduino, Raspberry Pi, and PICaxe are quite inexpensive.  With a few LEDs and pushbuttons you can learn simple programming to get started.  There are plenty of useful Ham Radio projects that you can find online.  And if you have an idea for your own gadget, you’ll have a lot of fun learning how to roll your own computer code. 

6.  Teach something.  You know how to do things others don’t, but would like to learn.  Are you already familiar with programming microcontrollers?  How about a club project to teach the basics to other members?  Or a demonstration on using Anderson Powerpoles?  Or properly installing coax connectors?

7. Become a “HAMbassador”.  Get just one person (or two, or three) interested in Amateur Radio.  Offer to demonstrate Ham Radio at the Senior Citizens’ center, Boy or Girl Scout meetings, the Rotary Club, or any similar organization.  Groups like that are always looking for an interesting speaker or activity.  A simple but impressive and effective demonstration is to bring an HT and ask for a “Roll Call”.  Notify your club in advance… all they need to do is reply with “This is (name, callsign) in (town).”  Remember that we’re Hams because we enjoy talking to other people.  The more Hams, the more contacts we can make.

8.  Get involved!  Join your local Radio Club.  If you already belong, attend the meetings.  Just about every club (not just Radio Clubs) has the same problem — 10% of the people do 90% of the work.  You don’t need to volunteer for everything… select an area that interests you, and help with that.  Even better, suggest an activity and then take the lead in organizing it.  Something as simple as “I’m going to set up a portable station at the park on Saturday morning, everyone is welcome to come by” can be a great time.  If you add “Free coffee and donuts” to your announcement, you’ll draw a real crowd 😉

9.  Stay positive, ignore the negative.  Don’t listen to the cranky old farts who insist that “Ham Radio is dying”.  Or better yet, point them here where they’ll find that the number of licensees is at an all-time high.  Participation in contests remains strong, even at the bottom of the sunspot cycle.  Manufacturers continue to introduce new models that we could barely dream of just a few years ago.  Hamfests that are well-organized and well-run are thriving. 

10.  Most of all, resolve to have more fun with Ham Radio in 2018!

Once again, my sincere best wishes to you and your family for a happy, healthy, and safe Holiday Season and New Year.

Thanks and warm 73,
John Bee, N1GNV
Quicksilver Radio Products 

Do something constructive. John suggests a first step. Your turn.

ESP32 and where we are now

Back a year ago, Hackaday found a Basic Interpreter Hidden In Esp32 Silicon (by Elliot Williams).  Documentation now exists at Read the Docs.

Now, for comparison, consider the TRS 80 Model I “introduced by Radio Shack on August 3, 1977….The initial price was $599.95, which included a typewriter-style (not membrane) keyboard, monitor, and cassette recorder. … It ran a Zilog Z80 at 1.77 MHz and came with 4K of RAM, and a 4K ROM of what was called Level I BASIC.” The display was 16 lines of 64 characters or 128×48 graphics. The cassette interface could run at up to 500 baud. 

Now consider the ESP32. It has 448 KB of ROM, 520 KB SRAM, another 8 KB of clock SRAM, and 1 K bit of one time write chip parameter memory. In addition to this, a basic system often has another 4 MB of external flash memory for program storage. See an Overview of ESP32 features. What do they practically mean?  That means this chip has 112 times the TRS 80 fixed memory, 130 times the working memory, and some extra. The external program storage would hold about 24 floppies worth of data.

There are three processors in the chip. Two are 32 bit and run at 240 MHz. The serial I/O will run at 960,000 baud. The third CPU is a special low power processor designed for long battery life while calling for the main processors and the radio only as needed. The two main processors run at 135 times the speed of the TRS 80 and handle four times the data on each cycle. The low power processor in its most battery saving but still alive mode still runs at nearly five times the TRS-80 speed.

And an ESP 32 ready to go can be had for under $10. Add in a power supply, keyboard, and display and you have an outlay less than a tenth the cost of a TRS 80 without considering inflation.

Torvalds priorities say a lot about success

At the Register: Linus Torvalds on security: ‘Do no harm, don’t break users‘ By Simon Sharwood — “Fixing for the sake of security alone means ‘all your work was just masturbation’

Torvalds was angry that developers wanted to kill dangerous processes in Linux, a measure that would have removed potential problems but done so in ways that users may not have enjoyed.

His long post on the matter suggested to security practitioners that “’Do no harm’ should be your mantra for any new hardening work.”

“And that ‘do no harm’ may feel antithetical to the whole point,” Torvalds adedd. “You go ‘but that doesn’t work – then the bug still exists.’ But remember – keep your eye on the endpoint, and that this is just the first step. You need to not piss off users, and you need to not piss of developers.”

Torvalds’ post explained his view that “… the number one rule of kernel development is that ‘we don’t break users’.”

“Because without users, your program is pointless, and all the development work you’ve done over decades is pointless.”

This is a story about the ‘big picture’ and understanding the reason for your efforts. Linus appears to have a good grip on this and that may be a major factor in why Linux is as popular as it is.

Self defense and Parakeets: Culture and history speaking

Two stories uncovered today provide a lot of insight into who we are and how we got that way.

One is about The American Indian foundation of American gun culture by David Kopel. This is on Wapo in the Volokh Conspiracy, a lawyer’s blog so it’s got reader harassment and bias to watch out for. The essay is based in part on Nicholas J. Johnson, David B. Kopel, George A. Mocsary & Michael P. O’Shea, “Firearms Law and the Second Amendment: Regulation, Rights, and Policy,” 2nd edition (Aspen Pub. 2017).

What today is called “American gun culture” is founded on American Indian arms culture. The convergence of Europeans and American Indians produced a new, hybrid arms culture. Although that culture has changed over the centuries, we can still find in 21st century arms culture the influence of the Anglo-Indian convergence along the 17th century Atlantic seaboard.
So one effect of the Anglo-Indian encounter was to foster a culture of widespread household gun ownership and widespread arms carrying. This was very different from conditions back in England, where the government was certainly not ordering people to always carry guns to the weekly (and mandatory) Church of England services.

The need for survival, both in protecting property and in obtaining food, were paramount concerns for the early settlers. Kopel notes a number of factors from history and tradition that evolved into what we see in the American variant of Western Culture today.

Parakeets, problem analysis and the beauty of inconvenience is about disruption for growth.

In his 2014 book Being Mortal, Atul Gawande tells the story of how Dr. Bill Thomas, a medical director at a nursing home in upstate New York, improved the experience of residents by challenging conventional elder care practices. Thomas believed that no matter how good the standard of medical care, the nursing home was failing its residents in three key areas: Boredom, Loneliness, Helplessness.

If they didn’t address these, the residents’ quality of life would suffer, with a knock-on effect on their physical health.

His solution started with 2 dogs, 4 cats and 100 parakeets.

This wasn’t a comfort pets introduction. It was an obligation disruption.

Residents were given the opportunity to adopt and name the parakeets. They could volunteer to walk the dogs and look after the cats. He followed up by encouraging staff to bring their children into the workplace and make noise. He replaced ‘safe’ and easy-to-maintain artificial plants with real ones that took more effort. He added vegetable gardens which needed tending.

Reading between the lines of Gawande’s account, it could be argued that Thomas wanted the introduction of these things to be difficult and disruptive. He did it in such a way that problems were inevitable, insisting that it happen all at once and with little warning. As a result, the staff and residents bonded together in solving the resulting challenges and a shared sense of humour over the temporary chaos.
The story inspired me to think about how breakthrough moments in product design often result from: Outside perspectives. New metrics. Shared purpose.

There’s a lot of insight there from many different directions. The Nursing Home management goal at its most basic is calm, order, and structure. That can conflict with its mission of patient health and vitality. The rewards for one are easy and comfortable; for the other difficult and challenging. 

Headless via VNC

Headless machines need a head somewhere. A barebones text terminal run via a serial port is the base option. A remote graphics desktop gets into the virtual machine and full access territory. Faster networks and more capable computers and graphics have made the full desktop option feasible enough that Raspbian takes very little to set it up. How to Set Up Easy Remote Desktop Access in Linux by Jack Wallen gets into the Ubuntu and Fedora situation and explains a few things that help fill in the current state of the technology.

Linux is a remarkably flexible operating system. One of the easiest means of understanding that is when you see that, given a task, there are always multiple paths to success. This is perfectly illustrated when you find the need to display a remote desktop on a local machine. You could go with RDP, VNC, SSH, or even a third-party option. Generally speaking, your desktop will determine the route you take, but some options are far easier than others. Once you understand how streamlined modern desktops have made this task, your remote administration of Linux desktops and servers (with GUIs) becomes much simplified.

Here’s the Raspberry Pi documentation on Virtual Network Computing.

Sometimes it is not convenient to work directly on the Raspberry Pi. Maybe you would like to work on it from another device by remote control.

VNC is a graphical desktop sharing system that allows you to remotely control the desktop interface of one computer (running VNC Server) from another computer or mobile device (running VNC Viewer). VNC Viewer transmits the keyboard and either mouse or touch events to VNC Server, and receives updates to the screen in return.

This one also has step by step instruction based on the Real VNC software. Here’s Instructable’s Setting Up a VNC Server on Your Raspberry Pi and at Adafruit, too.

As Wallen notes, there are a number of options and you can find more about them by a bit of research. Here’s a discussion on the Raspberry forums about the best VNC server to use. It’s another technology where you can experiment to see how it works without too much trouble or expense.

Guide to the Galaxy for Mobile App Developers has posted Don’t Panic: Mobile Developer’s Guide to The Galaxy, 17th Edition.  

More than 20 writers from the mobile community share their know-how in dealing with topics such as accessibility in mobile apps, UX design, mobile analytics, prototyping, cross-platform development, native development, mobile web and app marketing.

It is an easy to read rundown about what is going on with app development for mobile devices. At 325 pages there is enough meat to make a full meal yet it isn’t over-burdened with specification and datasheets. The graphics are rather cute but they don’t hinder the presentation.

The price is right and it’s easy to read and you can skim over sections that don’t go your direction. — well worth adding to your e-reader to check out in slack time.

The Amazing $1 microcontroller – a treasure chest for building modern electronic devices

The Amazing $1 microcontroller by Jay Carlson — “A new series that explores 21 different microcontrollers — all less than $1 — to help familiarize you with all the major ecosystems out there.” It is a good overview of what is out there for the electronics guiding much modern equipment as well as a guide to what counts and what doesn’t for these components. 

It’s time for a good ol’ microcontroller shoot-out. …

I wanted to explore the $1 pricing zone specifically because it’s the least amount of money you can spend on an MCU that’s still general-purpose enough to be widely useful in a diverse array of projects. …

Arm started out as a personal computer microprocessor when Advanced RISC Machines formed a joint venture between Acorn, Apple, and VLSI Technology to manufacture 32-bit processors for the Acorn computer. While Arm cores have grown in popularity as microprocessors for battery-powered systems (they are almost certainly powering your smartphone), Arm moved into the microcontroller sphere as well — the ARM7TDMI-S was probably the first Arm core that was used in microcontrollers — i.e., processors with completely self-contained RAM, flash, and peripherals. The Atmel AT91 and ST STR7 were probably the first microcontroller parts designed with an Arm core.

It’s important to understand the history of Arm because it explains a serious feature of Arm microcontrollers that differs substantially from the 8051 (the other multi-vendor architecture that dominates the field): Unlike the 8051, Arm is just a core, not a complete microcontroller. …

And that’s what I want people to think about as they walk away from this. If you’re an Arduino hobbyist looking where to go next, I hope you realize there are a ton of great, easy-to-use choices. And for professional developers and hardcore hackers, perhaps there’s an odd-ball architecture you’ve noticed before, but never quite felt like plunging into — now’s the time.

It’s an exciting time to be involved with electronics — whatever parts you choose to pick up, I hope you’ve enjoyed learning about what’s out there, and can get inspired to go build something great. Definitely leave a note in the comments below if you’ve got something to contribute to the discussion!

It’s rather in the TL; DR camp but that D in this case should be a “Do” rather than a “Don’t.” Carlson covers many aspects of microcontroller choice including part specifications to development environments and boards to debugging to compilers. Do explore this corner of low cost, general purpose, electronics development with Jay.