|Jack Ganssle's Blog
This is Jack's outlet for thoughts about designing and programming embedded systems. It's a complement to my bi-weekly newsletter The Embedded Muse. Contact me at firstname.lastname@example.org. I'm an old-timer engineer who still finds the field endlessly fascinating (bio).
For novel ideas about building embedded systems (both hardware and firmware), join the 30,000+ engineers who subscribe to The Embedded Muse, a free biweekly newsletter. The Muse has no hype and no vendor PR. Click here to subscribe.
August 29, 2018
My toothbrush has modes.
At the recommendation of my hygienist, we recently upgraded our old-fashioned simple toothbrushes to an electric model. It's a Philips Sonic Care, which she said is the only model I should get. For some reason she's down on the competing Oral B.
The thing clearly has a microprocessor in it as there are a few LEDs and it tracks brushing time. Every 30 seconds the brushing rate gets much faster for a half-second or so, telling you to move to a different quadrant of the mouth. After four such cycles the thing shuts off, which is logical since you can only have four quadrants.
I'm guessing it uses a micro's PWM output to control the brush rate. I'd really like to dissect the thing, but at $80 my wife might not be too pleased.
But recently it didn't stop after four cycles. It went into a fifth, so I've been manually turning it off, but was wondering if it would repeat these cycles forever. Mentioning this to my wife, she nonchalantly said "you must have it set to the wrong mode."
Mode? In a lousy toothbrush?
Turns out there's another switch I hadn't noticed which allows for more cycles. I'm not entirely sure what those are or the reason for this. So far, I haven't tried adjusting the modes out of fear it will enter some Twilight Zone of brushing catastrophe. Will it start brushing so furiously the thing will be like Steve Martin's sadistic dentist in The Little Shop of Horrors? Or maybe it will slyly brush a stroke or two, stopping at random intervals, provoking me to use it like a simple, non-smart toothbrush of yore.
Or will it keep going faster and faster, eventually imploding in a mouthal meltdown like a nuclear reactor's China Syndrome?
Bjarne Stroustrup wrote: I have always wished for my computer to be as easy to use as my telephone; my wish has come true because I can no longer figure out how to use my telephone.
Now I feel the same about my toothbrush.
Feel free to email me with comments.
Back to Jack's blog index page.
If you'd like to post a comment without logging in, click in the "Name" box under "Or sign up with Disqus" and click on "I'd rather post as a guest."
Recent blog postings:
- Customer non-Support - How to tick off your customers in one easy lesson.
- Learn to Code in 3 Weeks! - Firmware is not simply about coding.
- We Shoot For The Moon - a new and interesting book about the Apollo moon program.
- On Expert Witness Work - Expert work is fascinating but can be quite the hassle.
- Married To The Team - Working in a team is a lot like marriage.
- Will We Ever Get Quantum Computers - Despite the hype, some feel quantum computing may never be practical.
- Apollo 11, The Movie - A review of a great new movie.
- Goto Considered Necessary - Edsger Dijkstra recants on his seminal paper
- GPS Will Fail - In April GPS will have its own Y2K problem. Unbelievable.
- LIDAR in Cars - Really? - Maybe there are better ideas.
- Why Did You Become an Engineer? - This is the best career ever.
- Software Process Improvement for Firmware - What goes on in an SPI audit?
- 50 Years of Ham Radio - 2019 marks 50 years of ham radio for me.
- Medical Device Lawsuits - They're on the rise, and firmware is part of the problem.
- A retrospective on 2018 - My marketing data for 2018, including web traffic and TEM information.
- Remembering Circuit Theory - Electronics is fun, and reviewing a textbook is pretty interesting.
- R vs D - Too many of us conflate research and development
- Engineer or Scientist? - Which are you? John Q. Public has a hard time telling the difference.
- A New, Low-Tech, Use for Computers - I never would have imagined this use for computers.
- NASA's Lost Software Engineering Lessons - Lessons learned, lessons lost.
- The Cost of Firmware - A Scary Story! - A hallowean story to terrify.
- A Review of First Man, the Movie - The book was great. The movie? Nope.
- A Review of The Overstory - One of the most remarkable novels I've read in a long time.
- What I Learned About Successful Consulting - Lessons learned about successful consulting.
- Low Power Mischief - Ultra-low power systems are trickier to design than most realize.
- Thoughts on Firmware Seminars - Better Firmware Faster resonates with a lot of people.
- On Evil - The Internet has brought the worst out in many.
- My Toothbrush has Modes - What! A lousy toothbrush has a UI?
- Review of SUNBURST and LUMINARY: An Apollo Memoir - A good book about the LM's code.
- Fun With Transmission Lines - Generating a step with no electronics.
- On N-Version Programming - Can we improve reliability through redundancy? Maybe not.
- On USB v. Bench Scopes - USB scopes are nice, but I'll stick with bench models.