Scientists Build Wireless Bicycle Brakes 213
itwbennett writes "Computer scientists at a German university have built a set of brakes controlled using a small motor for a braking mechanism and a wireless signaling device to tell it when to brake and how hard. 'Making a popular set of bike brakes wasn't really the point of the project,' says blogger Kevin Fogarty. 'The project was to find out how to make the wireless connections between two components of a system that has to operate in real time – with milliseconds of difference between success and failure (PDF) – more reliable than systems that are normally connected by a wire.'"
Awesome... (Score:5, Funny)
Re:Awesome... (Score:4, Interesting)
I haven't had a head injury in a while, where do I sign up to try them out?
On a slightly more serious note, where can I buy some? I'll need about 3 dozen before the next local marathon bike race.
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And where do I buy the signalling device ? I would love to mount this on the side of my car, having all bikes around me lock up entirely, with hilarious results.
Joking aside, I do hope this guy thought about security.
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I don't think he really intends to build this. It's more of a study into the reliability of wireless controls.
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Doesn't mean you're going to try to sell the stuff you come up with.
Re:Awesome... (Score:4, Insightful)
I hope there is some sort of Make sure you mix up the levers and calipers so the radio pairs aren't installed together on the same bike.
Yeah, no thanks. This sort of technology adds multiple potential points of failure to a system that is currently reliable and simple.
Whereas a bicycle brake system can experience a cable failure (among others which are shared with a wireless system, such as pads) a wireless system can experience transmitter failure, receiver failure, radio interference, battery failure (transmitter or receiver). This team tries to mitigate that potential failure by adding more transmitters. That reminds me of a SNL skit - Christopher Walken "More Cow Bell"
In my time as a cyclist (3 decades), I've only experienced brake communication failure (broken cable) a couple of times - after which I learned to stop buying cheap cables and I've never experienced brake failure again.
I realize this is not a product that will likely see the light of day. It was an exercise in the reliability of critical communication as indicated by a quote early in TFA:
"Wireless brake" and "hit by a truck" sound the same to a cyclist
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a wireless system can experience transmitter failure, receiver failure, radio interference, battery failure (transmitter or receiver). This team tries to mitigate that potential failure by adding more transmitters.
I recommend they add a cable operated backup.
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There already is a backup braking system on your bike...think Flintstones...
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Yes. It's bad enough that cars have been converted to fly by wire (to lower weight, but adding more points of failure) but it's folly to take simple lightweight mechanical systems and add complexity. Except for lab research into technology.
However the good side of this is you'll be able to remotely start your bicycle's engine with a keyfob now. And the bicycle's pollution control system will be able to signal your dealer what that check engine light meant. Oh, code 54 meant 'bicycle's catalytic converter ne
Re:Awesome... (Score:4, Funny)
bicycle's pollution control system
That's a different industry - Fruit of the Loom makes the filters, and Gas-X makes the fuel system additive.
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Why not RTFA and notice it's presented as something that not a single cyclist will use.
When you are building things you start with the end object I take it? Rather than picking something that is trivial and cheap to work with?
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Cut him a little slack. He may still be suffering from one of the other head injuries he had a while ago...
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it's probably a lot less painful...
Says the person not on the bike.
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I doubt they even used a full bike. They probably just set up a bench of a tire and mechanical brakes and connected it to normal brake handles that were actuated by some sort of servo. Then right next to it the 'wireless' version. The tires were probably driven by a motor so that they could setup and run hundreds of hours of back to back automated tests.
It's not like they just threw a bunch of guys on bikes and said "So, how does this feel, lets tweak that carrier frequency.
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I suspect your brakes failing on a bike is considerably less painful than your controls on a jet aircraft failing. Assuming we count "died instantly" as more painful that "broke leg" even though I guess there might be no pain involved due to the instant part.
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As somebody who has crashed on a bike: Crashing on a bike is not that bad.
Well, we just had someone killed recently because someone flung open a door [www.cbc.ca], nailed the cyclist, knocked them into traffic, and they got run over.
Oddly, your one data point doesn't necessarily cover all cases of crashing on a bike. There are plenty of circumstances where crashing on a bike is anything but "not that bad".
And, if you've ever seen the guys doing downhill ... well, tell them it isn't all that bad or damaging to fall off
Re:Awesome... (Score:5, Insightful)
That said, the authors are faced with the horrible reality of wireless links - they are completely unreliable. Fundamentally. Period. The aether is a shared medium, and as such, you have to deal with collisions from other transmitters and interference from unintentional radiators (microwave oven, I'm looking at you.) The objective response time in this experiment is 150mS in the wireless link, and 100mS in the physical actuator. Ignoring the actuator time, 150mS is an abstract number without context. If you're brewing coffee wirelessly, 150mS to close the loop on the temperature control is effectively "instant." [no pun intended] However, if you're measuring RPM feedback on a turbine shaft, 150mS may be an eternity.
If you're placing the wireless link in the feedback path of a control loop, which these guys are doing, you have to account for the characteristics of the wireless link as part of the control loop stability analysis. Modeling packet loss and transmission delay as the equivalent phase shift and frequency characteristic of a classical analog component can be quite challenging. Further, the characteristics of interference sources may place you squarely in the "doomed from the start" category. If the above mentioned microwave oven can impair your wireless link for the duration of a bag of popcorn, your 150mS response time is irrelevant.
Wireless links and hard real-time control systems go together like fish and bicycles do.
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The aether is a shared medium, and as such, you have to deal with collisions from other transmitters and interference from unintentional radiators (microwave oven, I'm looking at you.)
After that we need to start talking about intentional interference that will screw your control system. Jamming a signal is fairly trivial if the control system is going to be reasonably priced. You will also see a lot of late stage design change failures when someone in a different department decides that an intervening panel needs some extra thermal protection and adds a metal backed sheet of insulation.
Just tag this "DoomedFromTheStart".
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They need some kind of safety critical system, and pushbike brakes seem like a good compromise.
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Which is exactly what I said.
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Works GREAT! (Score:3)
Works GREAT... until the battery dies and you hit a car.
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And think of all the fun when someone figures out a way to mimic the signal with another device! We'll know the future has finally arrived when a bully can fling a kid off his bike from across the street...
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If you think bullies are all about beating people up and taking their lunch money, you haven't spent any time around teenage girls or any adults in an office environment for that matter. Give people power over other people and some number of them will abuse it. In grade school that power is in terms of hitting puberty a few years before their peers and having extra muscle mass. People associate that with bullying because the effects are obvious and the kids are least equiped to deal with it. But even by
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The project is pretty ambitious as it is - they are designing *two* things that are not normally done on a bike: electrically activated brakes, and wireless brakes. A totally silly idea for a bicycle, but potentially useful for trailers.
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The project is not ambitious at all. Their main "contributions" are:
0. A poor-mans tutorial of a new modeling system. ...
1. Basic equations that model networks with packet collisions (they never reproduce them, but oh well), known for decades, provide same numbers as their model.
2. The off-the-shelf hardware works, in idealized conditions, about as well as the model predicts, and in line with how the manufacturer has designed it to work in the first place. No shit, Sherlock?
3.
There's no profit, there's no n
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I would hope being on a bike they can run off a dynamo.
So the brakes go off if the bike slows down? Or maybe they fail on (no, I've not read the article) -- in which case you can't release the brakes unless the dynamo is running, and the dynamo won't be running unless you release the brakes.
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One difference here is that a failure that affects one of your wireless links is more likely to affect both. A burst of interference microwave could easily knock out the connection to both brakes simultaneously. Basically there's only one medium the signal is being sent through, whereas with mechanical breaks there are two. You can alleviate that somewhat by using widely separated frequencies, but wide spectrum interference (such as a leaky microwave) will still cause problems.
Increasing complexity to reduce failure rates? (Score:2)
I guess I am not understanding the issue here but how is adding touch points reducing the failure rate? Regardless that is fixing a problem that does not really exist.
I know people who ride competitively, reliability is key and introducing more components that can break or add weight is not going to get acceptance. Modulation is key and I really doubt you can simulate that with any wireless system.
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I know people who ride competitively, reliability is key and introducing more components that can break or add weight is not going to get acceptance. Modulation is key and I really doubt you can simulate that with any wireless system.
That's what makes it an interesting exercise. It would be trivial - and non-newsworthy - to try to build a crappy on/of system that didn't work very well. It's far more interesting to try to figure out how to solve the problem and meet your criteria.
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'Making a popular set of bike brakes wasn't really the point of the project,' says blogger Kevin Fogarty. 'The project was to find out how to make the wireless connections between two components of a system that has to operate in real time...'
It was an academic exercise to test some theories on how to build high-speed, reliable wireless systems.
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And they have essentially added nothing new to what has been already out there for ages. Their only contribution is a tutorial in applying a stochastic modeling package to a not-very-interesting problem. They have limited themselves to on-the-air aspect of the system only, and on top of that all they show is that in TDMA fixed time slot assignment results in better reliability than random slot assignment. In the latter you get collisions and packet loss rate that's 5 orders of magnitude higher.
All this is d
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They do not even pretend to take into account various forms of interference, reliability of individual components
I was wondering about that yesterday when this story first broke. The article I read had no details other than the zillion digits in the reliability number, which told me immediately that someone wasn't doing the math right.
Turns out they're not doing the math at all. It's not a reliable brake, it's a reliable channel-assignment method.
They get that reliability number by putting conditions on the test and excluding all of the mechanical and electrical parts of the system.
I bet if I can put more conditions
Force-feedback built in? (Score:2)
To be useful, this would probably have to include some kind of force-feedback, so you know how hard you're pressing. You can't deduce this from lever position, because the brake pads wear down over their life. So, you'll need a motor in the handle, as well as in the brake itself.
On the up-side, it will mean you can incorporate front brakes on those BMX stunt bikes where some of the tricks involve spinning the handlebars all the way around.
Also also: "brake" == device for slowing something down, or the proce
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Keen! That's cool, I (obviously) didn't know that.
Also, having finally RTFA, I see that they've already met my other objection -- the way their system actually works is, it measures the *force* applied by the lever arm, and applies the same force at the brake pad. Of course this means you can't feel the sharply rising force when you really hit the binders, but it does mean that the reaction force of the lever really is (proportional to) the normal force on the brake pad.
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Stop whining (Score:5, Insightful)
This isn't about wireless bike brakes, it's about reliable, real-time wireless connections. Surely that's something nerds can find a use for?
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LED bike lights = tons of interference (Score:2)
I know someone who bikes a lot (From california to Massachusetts this year.) He has a wireless bike computer, which basically measuses each time your wheel goes around, and sends it wirelessly up to a little display on the handlebars. This worked great till he turned on his LED light, then the link was severed. By repositioning the light he could get the computer to work mostly. But computer isn't a key to functionality as brakes.
I think as a proof of concept this is fun, I would caution against
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hub brakes
Are you talking about drum brakes, or something else? Drum brakes are as common as mud (in .nl), and have been for at least 30 years.
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Not when they have to comply with FCC rules (one of its few reasonable ones) that require such a device to accept all interference from higher-ranked EM transmitters, even if it means degradation of performance. (Check the notice on any short-range EM transmitter device you have -- anything blue-tooth and/or wi-fi only should have it.)
Not a dig on FCC rules, this is actually a reasonable one. If you want to get your wireless brakes upped in communication priority (probably requiring you to own a piece of
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Jackass (Score:5, Funny)
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That's about the only sensible use of their research setup, actually. At least it's not a total waste that way. Because I'm convinced they wasted everyone's time doing that project. Not only there's no new science, but no new engineering either. It's just sad.
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This is hyperbole. You have to read the article. The time scale is nothing special and nothing new. They use off-the-shelf RF modules, configured per their appnote/datasheet. A typical GSM cellphone connection on the same network has fixed end-to-end delay that is well under 150ms. "Well" as in it can he half an order of magnitude less. Heck, they could have gotten their stuff to work similarly well, in controlled conditions as they have, by using two GPRS modems. It'd at least require some more effort to p
So does this mean that Belkin... (Score:2)
...Will make brakes that stop working for like, no reason?
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Yes, but they will be easy to replace with Netgear brakes, which stop working due to firmware updates, then start working with the next firmware update.
The devil you know is better than the devil you don't.
I doubt it. (Score:2)
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A lot of people said that about fly-by-wire vs. mechanical and hydraulic linkages.
Milleseconds? (Score:2)
The summary says with milliseconds of difference between success and failure, but the article and paper says it has to react within 250 milliseconds - that's 1/4 of a second. My cable brakes react much quicker than that.
Calling that mere "milliseconds of difference" is like saying something that costs $2.50 costs only "pennies".
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Your brake may be able to break extremely fast but as a human you can't. 250ms can be often faster then a human reaction especially if not prepared to break (surprised event).
Yes, it can take a human 250ms to react to a situation, but after I squeeze the brake lever, I don't want my braking system to take *another* 250ms to react.
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Very bad idea. (Score:2)
I like my brakes reliable. I know as a BMXer when the current trend is to go brakless I sound like a heretic. I'm old. I'm an old-school BMXer, [livejournal.com] I think the trend is stupider than these brakes, but at least someone who follows the trend knows they're riding without brakes unlike the people with these wireless ones.
I would be worried about other problems. When I ride my dork bike [livejournal.com] I have a pair of Cy-Fi Bluetooth speakers on my handlebars blaring AC/DC and Beastie Boys at people I pass. Every time I stop
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some stoplights have sensors that use EM waves to detect the presence of vehicles.
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I wonder if the induction system implanted into the road for detecting vehicles is interfering with your speakers at stop lights?
As for train tracks, they use electric current to turn on the crossing signals. Short the tracks with a wire and set the crossing warning system off (games we played as kids, a long, long time ago).
Batterys (Score:2)
Now why do need to have a Battery to have working brakes? On a bike?
on trains at least the brake systems fails to a stop state but any ways on a train why not have a cable any ways you need them to power it and the pipes for the air system.
Cranes, drawbridge motors, and industrial machinery all need power cables and or hydraulic tubes and running cat 6 / other data cables is next to nothing in scale.
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Trains fail to a stop state because they don't stop within feet when the brakes are applied, and are stabilized by having two tracks and no steering.
Jam on the brakes when someone isn't expecting it on a bicycle and they could easily be pitched to the ground.
The contact patch on a bicycle with rolling wheels is experiencing static friction because it isn't sliding. The contact patch on a bicyle with suddenly non-rolling wheels is sliding and experiencing kinetic friction, which is far less than static fric
They missed their mark in the spectrum by a bit :) (Score:2)
If anything, the system should have used optical transmission. It'd be fairly interference- and jam-proof, had they decided to use a modulated transmission -- modulated using a carrier and a PRN code so that multiple bikes in vicinity would not interfere with each other. GPS satellites do transmit at the same frequency, after all, and there's no interference.
Due to small distance between the handlebar and the actuator/receiver, you'd need a fairly powerful laser system to do any sort of large-area jamming,
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Optical transmission? How? By line-of-sight? That might work in good weather, for the front brake. But how are you going to get it to the back brake? And what if a drop of water or mud gets on the sending or receiving unit? Optical fiber is still a cable, so that's not a real change, either.
RF could work if more than just channel crosstalk is eliminated as a source of unreliability.
250 ms limit (Score:2)
I skimmed the PDF of their report. It's quite interesting, and despite the armchair quaterbacking on Slashdot, these people have done a pretty good job of using a life-critical system for testing out high-reliability wireless connections.
The one issue I have with their work is that they imposed an acceptability limit of 250 ms -- that is, there could be no more than 250 ms lag between a change in command (squeezing more or less hard on the brake handle) and the brake shoes actuating. That seems quite long
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The fact that they applied it to a "life critical" system is mirrors and smoke. It's a completely useless pretense, it did not affect their approach. They got some off-the-shelf RF communication modules, set them for either fixed-slot TDMA or random-slot TDMA, used a fairly "new" modeling system to show that the performance matches theoretical predictions known for decades, then wrapped it all up in a safety critical burrito. It's the filling that counts, and the filling was hot 50 years ago. Seriously. Thi
Some more dissing, I just can't stop (Score:2)
I guess the real reason the article reads like a solid WTF is that they are, supposedly, computer scientists with no experience in RF, controls, or safety-critical system design.
Not revolutionary or innovative (Score:2)
This could have been done for decades, it's just that nobody did because it has no advantages over conventional cable brakes and a shit-ton of safety issues.
Heh (Score:2)
I think it would be great to hack these, and then remotely trigger them for laughs.
Yeah, for some things I'll take the old-fashioned mechanical control systems.
Just Because You Can... (Score:2)
Doesn't mean you should.
They've had this for shifters already (Score:3)
http://www.wired.com/gadgets/miscellaneous/news/2008/07/shimano?currentPage=1 [wired.com]
Yeah, brakes are a different class, since they're a safety requirement rather than a nicety. It's especially nice in shifters, because it takes some of the tedious adjustment out of the picture.
Mostly, I think it's about clean aerodynamic profiles and simplicity: no wires means nothing to adjust. They've had batteries on bikes for a while, so this isn't novel on that score.
It's definitely for high-end road bikes only, real top-of-the-line stuff. I don't know if it will make a difference at that grade or not (it's way out of my league) but it sounds as if the doomsayers don't really know what it is high-end cyclists want and why. Yes, there are issues to be worked out, but I'm pretty sure they're aware of that.
A SYN flood at the Tour De France (Score:2)
I wonder if these guys are building reasonable security into their wireless connections?
Or are they doing what everyone else does, and create a wireless technology
and the security in later.
I realize this was just a proof-of-concept (Score:2)
but it does not hurt to keep all the other failure modes of mechanical brakes in mind (which may or may not be addressed by this device). These include:
- forgetting to reattach the cable, or deactivate the quick-release after service
- cable separates from soldered end
- binding nut not tight enough
- ice in cable housing makes cable immobile
- wet rims
- iced rims
- melted brake shoes
- melted coaster brake
- broken chain (on a fixie)
- derailed chain (on a fixie)
- brake-worn-rim separation
- internal hub leaks oil
Already here for cars (Score:3)
Welcome to OnStar, can I help the police violate your rights today?
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"Brakes". The word you're trying to write is "brakes".
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Granted I'm still pro wire vs wireless, that could have multiple variables make it go wrong, like a microwave or something. The only downside to a physical cable is that after prolonged use, eventually the cable will stretch. By this time, an aware rider would notice and either replace the cable or have it replaced. If it's not terribly broke, don't fix it.
I don't think the cables stretch so much as the housing compresses. But in any case, it's a gradual process, and the rider only needs to twist the cable adjusting barrel that most bikes have a few turns to make up for it.
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There is pretty much only in netherland that I saw bikes that brakes by peddling backwards. Personnaly, I find more convenient to have dedicated brakes since it allows to be ready to accelerate quickly despite I am currently braking.
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The backwards-pedal-to-brake feature is common on children's bicycles in the US, but I've never seen it on an adult's bike.
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Backpedal brakes are still common elsewhere on single-speed bikes made for young children.
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That said, I still love them on a low speed bike like a beach cruiser...
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Geez, give them a brake. Save your rage for spammers and trolls trying to pedal they're shoddy ideas.
(Ouch. My inner English teacher is wincing and glaring at me right now.)
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but there are military helicopters which use fly-by-wireless at a significant mass savings. All that mass that isn't in copper/insulation/supports can go into payload or armor or other "useful" stuff.
Can you provide a reference for this?
With as much RF shielding that military radio/navigation equipment gets for resistance to jamming, I'm really surprised that they'd go fully wireless for control systems.
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Can the motors in question apply the same amount of pressure that can be produced by squeezing the human hand?
Since they were designing an impractical proof-of-concept, I think it's safe to say that they could easily come up with motors that can provide the same (or more) pressure as human hands. When you have no real weight or energy concerns, anything is possible.
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When you have no real weight or energy concerns, anything is possible.
Well, not quite. Obviously, this is POC, but I bemoan that since systems like Di2 [shimano.com] work very well, but few use them because they add too much extra weight.
Not quite what? The designers of this system weren't trying to build a workable wireless brake system for bikes, they were only interested in the wireless control system, hence they had no constraints at all for the actuator motor - they could have used an 15 pound ABS actuator from a car powered by a 20 lb car battery and still met their design goals.
From TFA:
In this paper we are looking at a very tiny control problem
of precisely that sort. It is safety-critical, has hard real-
time requirements and does not have an obvious fail-safe
state.
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Man, I wonder where you could get power from on a moving bicycle that you would like to slow down?
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Oh that's all just Semitics. ... What? I'm misusing that word? ...That would explain a lot actually.
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It's not a question of not wanting to share the road, it's a matter of being pissed off at idiots who constantly ignore red lights and stop signs, swerve back and forth between lanes (including the oncoming ones), don't signal or even look before turning across in front of traffic.
Yeah, I hate car drivers too, but there's not much you can do about them, so I just learn to live with it.
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And they take up the WHOLE LANE with their cars.
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But now you can use your android device or Ipa/od Device to stop your bike!