 Poster: A snowHead
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A pal has had an idea patented for a gizmo that would fit on the end of a ski pole and measure the skiers speed.
Would anyone on here buy one, or is there such a device already available?
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Obviously A snowHead isn't a real person
Obviously A snowHead isn't a real person
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Well, the person's real but it's just a made up name, see?
Well, the person's real but it's just a made up name, see?
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T-Dub, not sure why I'd want one, unless I'm racing on closed pistes.
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Please stay up front does the gizmo need a lead-acid car battery to power up. Not my cup of tea to carry a car lead acid battery all over the mountains.
Come to think of it would strapping a hand held GPS system to the pole do the same job?
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Anyway, snowHeads is much more fun if you do.
Anyway, snowHeads is much more fun if you do.
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If it's on a pole won't the reading be inaccurate? The pole moves at a different speed from the skier, doesn't it? Wouldn't it be better at the tip of the ski? What benefit would it bring? Would it be readable while skiing, or would it just tell you things like maximum and average speeds over a run? There are already GPS-linked devices that do that, such as the Navman A300 and X300 gadgets.
Got any more detail?
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Just a gizmo for the sake of it.
Have you ever wondered how fast you just went?
No battery required - dunno about the GPS...
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I took a GPS out with me for the day - afterwards it drew a lovely map of my route around the Trois Vallees. It also declared my maximum speed to be 96 mph  , which (as anyone who has seen me ski will know) was clearly complete nonsense.
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My GPS does that (and more). I don't know how good an idea it is to be staring at the speedo while your bombing down a hill at DH speeds.
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You'll get to see more forums and be part of the best ski club on the net.
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I like the "speed test" zones that you find around...but they are always on a separate bit of piste. I'm not convinced that encouraging people to test their speed on an open piste is a good idea...which is how some poeple would use a device like this.
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T-Dub, "gizmo for the sake of it" suits me just fine! Presumably as there are no electronics it would be quite a cheap device, meaning it could make a stocking-filler present.
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snowHeads are a friendly bunch.
snowHeads are a friendly bunch.
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| hyweljenkins wrote: |
If it's on a pole won't the reading be inaccurate? The pole moves at a different speed from the skier, doesn't it?
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Only if you let go of it... !
More seriously, it depends on the time-frame of measurement. If it's recording over anything more than a pole-plant, then no, the average speed of both would be the same. If you're looking at spot speeds, then yes, there would be significant differences... particulalry when moving the device at a greater total speed than the skier is travelling forwards - this would produce a series of spot readings suggesting that for breif periods the skier is actually travelling backwards
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And love to help out and answer questions and of course, read each other's snow reports.
And love to help out and answer questions and of course, read each other's snow reports.
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People will now begin to nick poles in addition to skis. Would the darkersiders lose out?
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saikee, you ought to be able to make a detachable accelerometer - but I agree with those that say the pole isn't the right place for it.
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You know it makes sense.
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Apparently the Suunto watch (S6?) has a speed measuring thingy. No idea if it works well, at all , etc.
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Otherwise you'll just go on seeing the one name:
Otherwise you'll just go on seeing the one name:
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I fail to see how this can work? If it's not battery-powered (quote T-Dub: "No battery required") then how can it give any kind of readout and how can it take any kind of measurement? It either has to use wind speed (wildly inaccurate) or ground contact (even more wildly inaccurate) or it isn't going to work!
I can't believe that the technology exists that can measure velocity without electronics... but will sit on the fence of scepticism in the meantime until someone pushes me off one side or t'other...
An accelerometer is pretty darned useless as a speed-measuring device, by the way...
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Poster: A snowHead
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| T-Dub wrote: |
Would anyone on here buy one, or is there such a device already available? |
Surely your "pal" has done his homework on this, especailly given (presumably) a patent application?
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Obviously A snowHead isn't a real person
Obviously A snowHead isn't a real person
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| carled wrote: |
| An accelerometer is pretty darned useless as a speed-measuring device, by the way... |
Why? Inertial navigation systems in aircraft do provide this kind of function, to a high degree of accuracy. See here for more info.
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Well, the person's real but it's just a made up name, see?
Well, the person's real but it's just a made up name, see?
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Alastair,
The aircraft type instrumentation claims "two gyroscopes are used". That must be worse than carrying a car lead acid battery on the slope even if the sucker isn't battery-powered. Would I be interested in my skiing speed if I were ballasted with all these weights?
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saikee, if the slope is steep or slippery enough, they might help you go a lot faster! (although, knowing gyroscopes, they might also make it more difficult to turn!)
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Anyway, snowHeads is much more fun if you do.
Anyway, snowHeads is much more fun if you do.
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| Quote: |
Why? Inertial navigation systems in aircraft do provide this kind of function, to a high degree of accuracy. See here for more info.
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Yes and it also says
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| All inertial navigation systems suffer from integration drift, as small errors in measurement are integrated into progressively larger errors in velocity and especially position |
Simple physics dictates that the only way an accelerometer can measure velocity is to measure acceleration over a period of time and do the calculation. This fails to take into account the mass of the object and friction, which when combined will have a great effect on the velocity! Therefore I stand by my assertion that, particularly in this example, an accelerometer would be practically useless. Furthermore how can a battery-less device do the calculations required?
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saikee, I wasn't seriously suggesting an INS on each pole - just querying carled's rather sweeping statement.
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carled, I don't think the mass of the objet or friction are relevant. However, I would agree that an INS is hardly appropriate in this case - I just felt your previous comment was a little sweeping.
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Sorry, haven't read the whole thread but we have used a GPS watch (ostensibly for fitness and training purposes) as an on-board speedo. When running it struggles to hit 9mph but stick it on a pair of skis and watch those numbers roll. We measured the speed of intermediates (about 25mph on a gentle red - faster than I expected). Then I gave it to a maniac on a pair of Stockli Dominique Perrets and he hit 86mph on a closed piste we were using for testing. It saves fastest and average speeds and also updates every 3 seconds, which is a bit alarming when you're staring at your wrist waiting for it to refresh instead of ahead... gave up on that one as a bad plan.
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You'll get to see more forums and be part of the best ski club on the net.
You'll get to see more forums and be part of the best ski club on the net.
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Alastair, my "rather sweeping statement" as you so patronisingly put it, is a surprisingly accurate one. If you don't think the mass of an object or friction are relevant when using accelerometer style measurements for velocity, I strongly recommend you go and read up on some elementary physics prior to putting forward your opinions, chap.
If, for example, you take the simple position of the known stickiness of wet snow as compared to ice, then the same angle that the accelerometer is measuring will produce somewhat different results for the same skiier on those two different terrains. As Newton's laws so aptly demonstrate, a more massive object will take more force to get moving so I think you'll find that the mass of an object is, indeed, somewhat relevant...
If, however, you think I have got the wrong end of your stick, please feel free to enlighten me and the physics degree holder sitting some 20 feet from my desk.. 
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carled, I'm afraid I don't follow you. The factors that you mention (skier's mass and friction between snow and ski) will affect acceleration ... which an accelerometer will measure. To get to velocity, the only variable you then need is time (a = dv/dt). Admittedly, as you do the integration to get v from a, any systematic error will build up, but external factors have nothing to do with it.
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snowHeads are a friendly bunch.
snowHeads are a friendly bunch.
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carled, I suspect you ought to look at your own posts if you want to see patronising and inaccurate statements  .
[patronising mode] Accelerometers don't measure angles - that's inclinometers - but acceleration (that's why they're called ACCELERometers). Newton also made the important observation that the mass of an object was irrelevant when accelerating under gravity - it does require more force, but gravity provides just that extra force (weight) by acting on the larger mass. I suspect you shouldn't try teaching those of us who DO hold one or more science degrees (since you imply that you don't) how to suck eggs until you can do it yourself
[/patronising mode]
laundryman has said most of what I was going to. The thing I would be most concerned about in some kind of inertial method of speed measurement would be how quickly the integration would need to be done, as there will be some pretty high instantaneous peaks as pole (or ski if it were attached to that) hits ground/mogul/whatever, so would not sampling rate and S/N of the measurement device be fairly important to stop baseline drift?. On the whole, aeroplane accelerations won't be anything like so jerky, so won't need to accomodate those peaks. However, not having ever designed a INS I may be talking out of some random hole here.
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And love to help out and answer questions and of course, read each other's snow reports.
And love to help out and answer questions and of course, read each other's snow reports.
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GrahamN, love your coding
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GrahamN, Well forgive me for saying so, (I doubt you will considering your condescending attitude, but anyway) but aren't you the self-important twerp? I am, of course, grovelling as I type, in awe of your Dr. Science status.
This forum is rapidly becoming a home for backslapping, self-aggrandising guffawing buffoons. Honestly, take a look at yourself in your little cliques of "those who should not be disagreed with". At the slightest sign of anyone daring to stand up to an "esteemed member of the establishment" (you know who you are) you all close ranks and start dishing out the supposed witticisms and waiting for your braying clan to come and applaud your efforts. It's pathetic, to be frank, and I think there's been a sea change in this forum over the past few months that is akin to the attitude that Kevin Mcclean refers to in his post about resort workers to punters... no prizes for guessing who the resort workers are...
There are several on here who are helpful, informative and pleasant and, unfortunately a growing number of those who aren't. Yes, I admit I've been somewhat patronising in my own responses, but this is a self-defence mechanism for the crap I've been getting from a minority of the establishment on here. I don't care how many science degrees people have or how long they've been members on here - if they act in a pompous and condescending manner then I'm afraid I will stand up for myself until or unless I'm banned - which I believe is all too likely an outcome seeing the way things are going on here.
Back to the subject concerned - although I may have been mis-informed about the physics involved (and my colleague with the degree is not in the office to flog at present) then my other contention about no battery = no processing power still stands. How is a manual accelerometer going to manage to process the necessary data readings to produce velocity readings without a battery? You also all seem to have assumed (and I'm sure you'll correct me if I'm wrong) that the "end of the pole" being talked about is the extreme end nearest the snow, rather than the bit in the hand that doesn't move anywhere near so extremely as the other end...
Last edited by So if you're just off somewhere snowy come back and post a snow report of your own and we'll all love you very much  on Mon 20-03-06 17:13; edited 2 times in total
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You know it makes sense.
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Do they have accelerometers on Easyjet planes?
How does the weight of skis in the plane affect them?
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Otherwise you'll just go on seeing the one name:
Otherwise you'll just go on seeing the one name:
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Wear The Fox Hat, inside I'm laughing, believe me... Call for the doctor, for I fear my sides have split, as the great Blackadder once said. And they said that the golden age of comedy was dead.
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Poster: A snowHead
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| carled wrote: |
| ...my other contention about no battery = no processing power still stands. How is a manual accelerometer going to manage to process the necessary data readings to produce velocity readings without a battery? You also all seem to have assumed (and I'm sure you'll correct me if I'm wrong) that the "end of the pole" being talked about is the extreme end nearest the snow, rather than the bit in the hand that doesn't move anywhere near so extremely as the other end... |
Um, you can power things without batteries. All you need is a way of generating enough electricity, and that can be done through light, heat, wind, etc.
Also, unless one is swinging the pole over the snow, so that it covers ground it has already been over more than once, then the tip and handle of the pole will cover roughly the same distance coming down a run.
Think of it, you reach forward with the tip - it travels say 50cm ahead to the handle. It then stays there, and the handle catches up with it, and passes it, so the handle is maybe 50 cm ahead of the tip.
Then there are those who don't plant their poles much at all, in which case the distance travelled is going to be identical at any part of the turn, not just over the length of a run.
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Obviously A snowHead isn't a real person
Obviously A snowHead isn't a real person
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Wear The Fox Hat,
Scientific definition of potential energy = mass x height
More skies means more dead weight for the plane to gain height and so "more fuel" is needed if the engine is capable of providing the additional output.
It so happened in my last trip my brother's plane from Oslo to Munich was too heavy and about 100 pairs skis had to be off-loaded to enable the plane to take off. On arrivial about 100 skiers registered with the German carrier to have the skis delivered to the resort,
My brother called the carrier regularly and the skis were delivered by a flight from Munich and then driven to St Anton to be made available at 7am before we started our first day skiing. My brother were threatening them with the cost of hiring charges for the family of 4. The roads from Munic to St Anton were pretty bad but the courier company must be doing this all the time to provide such a prompt service.
Not so sure with the service from Easyjet though.
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Well, the person's real but it's just a made up name, see?
Well, the person's real but it's just a made up name, see?
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| bh1 wrote: |
| T-Dub wrote: |
Would anyone on here buy one, or is there such a device already available? |
Surely your "pal" has done his homework on this, especailly given (presumably) a patent application? |
I don't know about T-Dub's mate's, but there are plenty of patent applications (and patents) for useless rubbish.
The power shouldn't be a problem; a solar device or a dynamo (presumably wind powered). If it's on a pole, the instantaneous reading would probably be wrong for ski speed, but over even a short time (10 secs?) would probably be correct. The mystery is how the speed is measured. Air speed? Hopelessly inaccurate unless you compensate for wind somehow. Ground contact? Optical? Both possible, both likely be inaccurate. GPS? Bit pricey but OK so long as you have the necessary view of the sats (which you often don't in my experience). Accelerometer? Bit pricey, bit hefty, OK so long as you know the starting speed (such as 0).
T-Dub, do you have the number of your mate's patent application? I've just found one which uses an optical system (is your mate called Richard Kirby, by any chance) and another using ultrasound (by 3 German guys).
Last edited by Well, the person's real but it's just a made up name, see? on Mon 20-03-06 17:54; edited 1 time in total
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saikee, sorry, it was a little joke between me and carled from another thread (thankfully carled has a sense of humour and saw the funny side of it)
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Anyway, snowHeads is much more fun if you do.
Anyway, snowHeads is much more fun if you do.
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| Wear The Fox Hat wrote: |
| Um, you can power things without batteries. All you need is a way of generating enough electricity, and that can be done through light, heat, wind, etc. |
Quite so. My bets would be on solar power or the piezo-electric effect. In fact, the accelerometer may use the piezo-electric effect: more acceleration gives more force of some mass against the crystal, causing more compression and greater voltage. Perhaps you can ingeniously use the instrument to generate its own power in this way - that would certainly be worth a patent. I don't know for certain if either power source is really practicable for the application, but I wouldn't dismiss them out of hand without a lot of engineering knowledge.
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You'll need to Register first of course.
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I go away for 10 minute to get a cup of strong coffee expecting a real scrap and people have gone and turned all reasonable... maybe it's a cunningly concealed trap for the unwary, so I shall tread carefully.
I would *really* love to see a solar-powered version of a gadget like this. the entertainment value alone of seeing a skiier with a solar panel strapped to his head... no, it's too good, stop me...
Maybe wind power? A few of those little plastic daffodil type thingies strapped to various locations on the body...? I would pay good money to see that coming down the piste...
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| carled wrote: |
I would *really* love to see a solar-powered version of a gadget like this. the entertainment value alone of seeing a skiier with a solar panel strapped to his head... no, it's too good, stop me...
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Why not use one of these...
http://www.voltaicsystems.com/bag_pouch.shtml
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carled, I've got a solar powered watch / altimeter / compass / thermometer that I wear on my wrist on the slopes (underneath jacket and glove most of the time) and it works just fine.
What do you know about the piezo-electric effect?
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You'll get to see more forums and be part of the best ski club on the net.
You'll get to see more forums and be part of the best ski club on the net.
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One of the patent applications I refermentioned earlier uses rechargeable batteries, reasonable enough if you're using an optical system, I suppose.
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Didn't even suspect that such a thing existed and now I know, I sort of want one...  But maybe not at that price...
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