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Hacking my “smart” toothbrush

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Re: Hacking my “smart” toothbrush

#251

Post by conradev »

tzs wrote: post #193
version_five wrote: post #158

Earlier quoted context omitted.

Engineer gonna engineer. Someone probably just had the time and misplaced passion for security, and when they explained at the weekly standup that they'd added lockout after three attempts, everybody just nodded and moved on.

This has long been a temptation for engineers. 40 years ago the textbook in the digital electronics class I took at Caltech had a chapter called "The Engineer as Dope Pusher" that talked about it. It gave as an example clothes dryers. The way most home clothes dryers working back then was you put the clothes in, you turn a dial on a timer to the number of minutes you want the dryer to run, and you press start. The me…

> If the mechanical timer ever broke the repairperson would have replacements in their van

> That digital timer has no advantage to the user over a mechanical timer. But it has disadvantages.

The mechanical timer is known to degrade over time, which is why the repair person has spares in their van. Does the digital timer really have no advantages? Will it ever fail and need to be replaced? How much more does it cost?

Yes, engineers are tempted to use shiny tools all of the time. Evaluating whether or not the tool is right for the job is _hard_. But it feels wrong to say that novelty is the only motivation behind upgrading tools?

The digital timer was made by an engineer, too, who designed it to be a more reliable replacement for faulty mechanical timers. It has both advantages and disadvantages compared to mechanical timers, which is why the engineer made it in the first place?

Re: Hacking my “smart” toothbrush

#252

Post by Kirby64 »

tzs wrote: post #193
version_five wrote: post #158

Earlier quoted context omitted.

Engineer gonna engineer. Someone probably just had the time and misplaced passion for security, and when they explained at the weekly standup that they'd added lockout after three attempts, everybody just nodded and moved on.

This has long been a temptation for engineers. 40 years ago the textbook in the digital electronics class I took at Caltech had a chapter called "The Engineer as Dope Pusher" that talked about it. It gave as an example clothes dryers. The way most home clothes dryers working back then was you put the clothes in, you turn a dial on a timer to the number of minutes you want the dryer to run, and you press start. The me…

Mechanical timers are fine, but digital circuitry is by far going to be more reliable if designed properly. There isn't anything physically moving, so the failure modes are much more restrictive. Also, digital provides advantages with offering variable timing on a dryer, for instance, based on the input of a moisture sensor. Mechanical methods for that are more complicated.

Additionally, I would be very surprised if the digital solution is not cheaper to make. Maybe not when first originally introduced, but nowadays it very likely is.

You're right that repair-ability is hurt in some ways... but the industry has moved to compensate. You can buy boards and replace them. They aren't inherently hard to service, because the form factor doesn't really have limitations.

Re: Hacking my “smart” toothbrush

#253

Post by arbitrage »

Dead_Lemon wrote: post #147
rddydydyd wrote: post #43

dumbest waste of materials. for what? just to waste more battery when i travel with it without a charger?

I'm still trying to figure out why people need a battery powered toothbrush over a conventional one, let alone one that needs apps and verifiable replacement heads.

People don't. A company wanted a new market, so they made one and convinced enough people that they do in fact want this superior brushing technology.

Ooooh, so shiny.

Re: Hacking my “smart” toothbrush

#254

Post by mrelectric »

whiddershins wrote: post #243
gwbas1c wrote: post #179

Earlier quoted context omitted.

Reminds me of the time I bought a lamp plug-in dimmer on Amazon, and I noticed that my "personal massager" was one of the "frequently bought with" items. My wife and I had a lot of fun that night! Turns out the "personal massagers" work a lot better that way.

Wait, personal massagers are generally battery operated. How does this work with a plug in lamp dimmer.

The Orginal Magic Wand™

Re: Hacking my “smart” toothbrush

#255

Post by dpedu »

I've owned several of these toothbrushes - it's worth pointing out that they work just fine with 3rd party heads with no chips in them. At least, the 2 models I've owned do.

Something bizarre I noticed about these Philips toothbrushes is that they fail on a reliable schedule. I owned 3 of the "4100" model and they all failed after exactly 13 months! What's crazier, is that they all failed in the exact same place. There's a metal piece that protrudes outside of the case where the heads attach. Inside the case, this piece clamps to the part that creates the vibrations using a single screw through a cast zinc/nickel block. On _all_ of my brushes, this block cracked right through the screw hole.

What's cool is that the vibration motor uses a magnet of similar strength of hard drive magnets, so now I have some nice strong magnets on my refrigerator.

Re: Hacking my “smart” toothbrush

#256

Post by joelfried »

Kirby64 wrote: post #252
tzs wrote: post #193

Earlier quoted context omitted.

This has long been a temptation for engineers. 40 years ago the textbook in the digital electronics class I took at Caltech had a chapter called "The Engineer as Dope Pusher" that talked about it. It gave as an example clothes dryers. The way most home clothes dryers working back then was you put the clothes in, you turn a dial on a timer to the number of minutes you want the dryer to run, and you press start. The me…

Mechanical timers are fine, but digital circuitry is by far going to be more reliable if designed properly. There isn't anything physically moving, so the failure modes are much more restrictive. Also, digital provides advantages with offering variable timing on a dryer, for instance, based on the input of a moisture sensor. Mechanical methods for that are more complicated. Additionally, I would be very surprised if…

There is something physically moving: the machine itself. You can't wash or dry clothing without moving it around. Given that the entire machine moves (and on spin cycles, reasonably quickly), you need to make sure your circuitry is capable of handling the strain.

As a homeowner, I wish someone (anyone!) still sold reliable analog appliances that just did their job simply and made repair parts and schematics reasonably available.

Re: Hacking my “smart” toothbrush

#257

Post by marcod »

uxcolumbo wrote: post #148

It's a toothbrush. Why does it need all this tech and an app? It's better to think about sustainability. I had an Oral B IO electric toothbrush. The retail price is nuts and the brushes are expensive and can't really be recycled. Imagine millions of these out there slowly rotting. I gave up on the IO and bought this one instead. Simple design and battery lasts longer too. https://www.trysuri.com/

I mean, you can find disposable electric toothbrushes in stores ... sustainability does not seem to be among the primary design criteria.

Re: Hacking my “smart” toothbrush

#258

Post by JadeNB »

conradev wrote: post #251
tzs wrote: post #193

Earlier quoted context omitted.

This has long been a temptation for engineers. 40 years ago the textbook in the digital electronics class I took at Caltech had a chapter called "The Engineer as Dope Pusher" that talked about it. It gave as an example clothes dryers. The way most home clothes dryers working back then was you put the clothes in, you turn a dial on a timer to the number of minutes you want the dryer to run, and you press start. The me…

> If the mechanical timer ever broke the repairperson would have replacements in their van > That digital timer has no advantage to the user over a mechanical timer. But it has disadvantages. The mechanical timer is known to degrade over time, which is why the repair person has spares in their van. Does the digital timer really have no advantages? Will it ever fail and need to be replaced? How much more does it cost?…

> The mechanical timer is known to degrade over time, which is why the repair person has spares in their van. Does the digital timer really have no advantages? Will it ever fail and need to be replaced? How much more does it cost?

Surely the expected lifetime of a digital timer is shorter than that of a mechanical timer.

Re: Hacking my “smart” toothbrush

#259

Post by eschneider »

version_five wrote: post #158
Voklen wrote: post #127

Earlier quoted context omitted.

I have a third party brush head for my Philips Sonicare with none of the smart features and no electronics in the head (there's an air gap where they usually are) and it still works fine. This makes me wonder all the more why they put the effort in to secure the head.

Engineer gonna engineer. Someone probably just had the time and misplaced passion for security, and when they explained at the weekly standup that they'd added lockout after three attempts, everybody just nodded and moved on.

More likely the toothbrush had to pass a security audit. And the last thing you want to have to explain to management is the DEFCON presentation on toothbrush security flaws. No. You. Don't.

Re: Hacking my “smart” toothbrush

#260

Post by zerd »

mkskm wrote: post #245
chrisstu wrote: post #152

Earlier quoted context omitted.

This is a nice idea. The problem is longevity. I'd be willing to bet this product disappears after a few years (best case scenario) and you are left with no ability to buy new heads and end up binning the brush. So net net you probably waste more than buying a Philips/Oral-B brush that likely has 10+ years of support for brush heads, which have a far lower environmental impact than replacing the brush. In terms of co…

They make third-party compostable bamboo brush heads for Philips now, e.g. https://thesustainabletomorrow.com/products/bamboo-heads-phi...

This is probably why they're doing all the electronic shenanigans, so they can later verify that you're using a Genuine Authentic® brush head.
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