Accelerometer
Charles Carroll
It is a combination rate watch, self-timer, and can display stroke rate, and
even analyze boat check.
Apparently it is very new. At present it is still unavailable on this side
of the pond, but I was told that it was introduced at Henley earlier this
year, and is currently being used i the UK.
Any information would be greatly appreciated.
Cordially,
Charles
David Biddulph
geographic location but then doesn't seem easily to allow a reselection. I
guess that it's cookie-based? The selection is through
http://www.active-tools.com/select.aspx?url=rowing-rate-meters.aspx but one
doesn't seem to be able to get back there from the front page. The do say
that it's available in the USA & Canada as well as the UK, but not elsewhere
in the world.
--
David Biddulph
"Charles Carroll" <charles...@comcast.net> wrote in message
news:yIednXERGJFDkWDV...@comcast.com...
Stelph
wrote:
I can tell you about them, I have one! Ive been using it for several
weeks in the UK and it made the trip across to the US with me for the
Head of the Charles Weekend where I raced in the Club single.
I have to say the design and use of the ratemeter is very intuitive,
the unit comes with two brackets to stick onto the boat, one which can
be attached to the bolts on your footplate (probably best to use this
one in your single) and with suckers on that you can quickly attach to
whatever other boat that you are rowing in, its very quick and easy to
move between boats and has meant that when ive been switching rapidly
between boats (i.e for pairs trials at my club) its very easy to move
it between boats. There is only one big button that is on the top of
the unit and it is completely waterproof and very light.
As I understand it there are essential two models, the cheaper model
(with the blue button) that I have at the moment that takes your rate
and also displays the time (essential in a ratemeter at club level,
cant believe that NK only have that on their most expensive models!).
You can also use it as a ratewatch by using the button to track
strokes.
The slighly more expensive version (with the yellow button) also
measures the check of the boat, and can time you from a standing start
to when you wind down, and you can also get a very clever fibre optic
heel switch which is really clever and allows you to start and stop
the watch by moveing your heels apart rather than reaching down and
pressing a button which is always difficult to remember to do after a
race :-)
Basically, I love it, its a really useful ratemeter and a solid and
dependable alternative to getting an NK. The only addition I would
like to have ould be having a light so that you can see the screen at
night, but that may be someting they implement later on following
feedback from customers, lets see.
I believe it is now available in the US (or at least the US site has
now been activated) since it was on display for people to see and use
at the Head of the Charles, one of the guys who runs the company rows
at my club so Ill point this thread out to him so he can give you more
accurate answers/respond to questions if you're interested?
John....@googlemail.com
We launched them at Henley Royal and have been selling in them in the
UK since then. We have (inevitably) had a few teething problems but
these have been addressed and sales are going well.
We also launched them at the Head of the Charles over the weekend and
they got a very good reception. They are not yet in stock in the US
but they will be in about 3 weeks and we will then fulfil both the
orders we got at the HOC and any new orders.
I can be contacted at jo...@active-tools.com if you have detailed
questions and I will answer anything posted here.
Henning Lippke
> I will answer anything posted here.
Please do so.
When will it be available in central europe? I'd like to have one.
Charles Carroll
Thank you very much. I don't think the Accelerometer could be better
described. It was especially heartening to hear that you are enjoying yours
so much. RSR is such a great resource.
I just ordered an Accelerometer. It is to be a gift to a friend. We scull
together frequently, and he has recently done me a great service. I suspect
he is going to love it.
I ordered the yellow button with the fibre optic linked source between the
heels.
On second thought, maybe this wasn't such a good idea. I am sure I am in for
it now. I suspect I am going to be hearing a lot about how we need to be
faster.
Cordially,
Charles
Justus J.
Henning,
the time Germany was the centre of Europe has long been gone :-)
Justus
John....@googlemail.com
We don't yet have a firm launch date for the rest of Europe, although
it will be before the end of the year. The delay is mainly because the
market for the Rate Meters is somewhat different to that of the
rigging tools we have been selling for the last 5 years so we need to
make sure we distribute them in the best way possible.
If any RSR readers feel they can't wait that long please email me
direct at jo...@active-tools.com and we will sort something out for
you.......
Stelph
wrote:
Glad to hear you've gone to buy one, I couldnt recommend this highly
enough to be honest. Something I didnt mention is that the
accelerometer is very sensitive and accurate, it was even able to pick
up my rating when sculling arms and body only, plus it is able to re-
calibrate itself to whatever angle it is at, so no worries about
having to claibrate it the first time you get in the boat or worry
about what happens if the suction holder moves mid outing or whatever,
it really is just stick it in the boat and go.
Am sure your friend will love it!
lpu0...@rdg.ac.uk
pretty well! My coach when I was at Reading rows also rows at his club
and got us a prototype for our April training camp last year. As
Stelph said, it's really easy to swap between boats and worked
flawlessly for me whilst I had it. The check meter was really useful;
although I couldn't really quantify what the units represented, that
didn't really matter as I knew I was going for as low as possible with
the number, and I never had any problems getting it to pick up a rate
with the accelerometer rather than magnets.
I would definately buy one if I didn't already have a rate/speed
meter, and would recommend them to anyone, especially if they were
used in a club situation where they'd need moving boat to boat.
Carl Douglas
I chuckled over your remark that check measurement was useful & that
your not being able to decide what the check measurements meant didn't
really matter ;)
Ponder a mo, as very few of us have done, the less than wholly simple
significance of check. Suppose you check sharply but extremely briefly
- what is lost? Suppose, instead, that you check a bit more gently but
for longer - is that better or worse? Some of us here would suggest you
should consider not the intensity of check but the product, summed over
time, of intensity & duration of check. Now a meter which told us that
would be really handy, & its results would be much more meaningful.
Cheers -
Carl
--
Carl Douglas Racing Shells -
Fine Small-Boats/AeRoWing Low-drag Riggers/Advanced Accessories
Write: Harris Boatyard, Laleham Reach, Chertsey KT16 8RP, UK
Find: http://tinyurl.com/2tqujf
Email: ca...@carldouglas.co.uk Tel: +44(0)1932-570946 Fax: -563682
URLs: www.carldouglas.co.uk (boats) & www.aerowing.co.uk (riggers)
Charles Carroll
I have a simple question. Is it possible to scull without checking at all?
David contends that he is faster when he reduces check, or can completely
get rid of it, and thus thinks that it is crucial to work on this. The way
he does this is to open the scupper on his 24 and listen to the sucking
sound. He says that when the sound stops it is a signal that he is checking.
But as you say, you can reduce it two ways. You can check " sharply but
extremely briefly," or check "more gently but for longer." Did you mean for
us to infer that it is impossible to reduce check completely?
So far the only secret I have been able to find with check is keeping a
light, loose grip on the oar handles at the entry.
Assuming that you have made a proper release, and managed to complete the
recovery with the least disturbance of momentum, a "light, loose grip on the
oar handles" will let you feel the oar handles moving towards you. And when
the oar handles move towards you, and when you can seamlessly join yourself
to this movement, it seems to me that check all but disappears. Another
advantage is that the drive begins light and effortlessly, the oar handles
feel alive in your hands, you stand on the stretcher, and the shell flies.
On the other hand, maybe I am checking and just don't understand that I am.
Cordially,
Charles
John....@googlemail.com
> should consider not the intensity of check but the product, summed over
> time, of intensity & duration of check. Now a meter which told us that
> would be really handy, & its results would be much more meaningful.
>
> Cheers -
> Carl
As usual, Carl gets to the heart of the issue. However what he
proposes is exactly what the Check function on the ActiveTime shows
you.
As you can imagine, the algorithms needed to achieve all the functions
that the product offers are quite sophisticated - the firmware has
over 5000 lines of code!
Charles Carroll
>> should consider not the intensity of check but the product, summed over
>> time, of intensity & duration of check. Now a meter which told us that
>> would be really handy, & its results would be much more meaningful.
> As usual, Carl gets to the heart of the issue. However what he
> proposes is exactly what the Check function on the ActiveTime shows
> you.
> As you can imagine, the algorithms needed to achieve all the functions
> that the product offers are quite sophisticated - the firmware has
> over 5000 lines of code!
John,
That's it! I just ordered a second one for myself.
Cordially,
Charles
Carl Douglas
Just one question, John:
Where may we see how this check function is computed?
Thanks -
Carl Douglas
Theoretically, yes, Charles. And I think it a pity that we do not
consider this much, or at all, as a possible objective.
In practical terms, I doubt it is usefully (= gainfully) attainable, but
people used not to think a triple Salchow possible.
Rowing is a very simple pursuit & not one making large demands on
athletic dexterity, so it tends not to think too deeply about technical
possibilities with which most rowers might prefer not to challenge
themselves.
That's a pity, since there do appear to be aspects of technique which,
when not prejudged, might usefully be explored & might perhaps yield
gains in performance for a given work rate. The trick for a low-check
(I prefer that to the term "checkless") catch must be to engage the load
on the blades significantly before _any_ pressure is applied to the
stretcher. This is a perfectly feasible objective, in inertial terms it
presents no analytical obstacles & it may well be attainable by a
skilled gymnast. There may be a price to pay to achieve this result or
there may not, & that price, imposed on the rower, may or may not exceed
the benefit. That benefit should come from reduced drag resulting from
a more constant boat speed &, just perhaps, from a consequent reduction
in pitching.
What is depressing is that rowing prefers not to explore those areas
where analysis suggests that gains are accessible. Just as we prefer
not to row deeper, complaining that it feels harder (of course it does!)
& then trying to justify it by specious arguments that looming must
immediately rob us of any benefits. Just as we cling to the notion that
blades work by pushing water. Just as we row as if the boat is heavy &
runs constantly & we are light & have to decelerate to take the catch.
Cheers -
Carl
PS Charles - lest you doubted the tale of the cake:
http://www.rutgerspek.nl/cpg144/displayimage.php?album=70&pos=66
That's the "before" picture. There are no "after" shots - no surprise
since it was a cake to die for. Another cake was awarded to the swimmer
of the event who, tightwad schoolboy that he is, shared it exclusively
with his own clubmates.
PPS One elderly & respected member of Salland RC is said to have used a
disintegrating handful of "my" cake to practice the Belgian art of
Entartement - on the face of a mutual friend from Germany. You'll be
happy to know that not a crumb of cake was wasted & no wars were
started, though who licked what off whom I'd prefer not to know....
C
John....@googlemail.com
>
> Thanks -
> Carl
I'm afraid that we don't publish exactly how this is calculated,
although the fundamentals are exactly as you proposed. The reason is
that it took a lot of work to develop an algorithm that gave results
that were both meaningful and stable and for the moment we would like
to keep this proprietary.
Out of interest, we are currently working with a leading rowing
biomechanist and when this work is complete we hope to be able to give
people more guidance on how to use the check readings.
Henry Law
> We manufacture these units so I can answer any questions.
sooooo ... have you been lurking for decades in the group, waiting for
something to post about, or did someone tip you off?
Anyway, you're welcome. Your wee gadget sounds really well designed and
I hope you're very successful with it. Keep posting!
--
Henry Law Manchester, England
Carl Douglas
Many thanks, John, for that quick response.
Obviously your code is proprietary. Anything worth doing, like this,
take hard work. And, unlike some in this sport, I think hard original
intellectual work deserves protection.
That said, we recently had an interesting discussion on the significance
of erg data. Data derives from measurements & computation & either has
absolute meaning & significance (although it may have limited numeric
accuracy due to limitations in the means of measurement) or it has very
little. I'm sure that, before you wrote 5000 lines of code, you had a
precise mathematical definition of the output result. So I suppose you
can exactly state the computed meaning of an output without revealing
the computations that got you there or any other proprietary matters?
Cheers -
John....@googlemail.com
> something to post about, or did someone tip you off?
>
Someone did tell me about the discussion although I do read the group
and have, very occasionally, posted.
I like the wide range of viewpoints you find here and the fact that
people appear to genuinely try and understand other people’s points of
view!
John....@googlemail.com
> absolute meaning & significance (although it may have limited numeric
> accuracy due to limitations in the means of measurement) or it has very
> little. I'm sure that, before you wrote 5000 lines of code, you had a
> precise mathematical definition of the output result. So I suppose you
> can exactly state the computed meaning of an output without revealing
> the computations that got you there or any other proprietary matters?
>
> Cheers -
> Carl
We actually subcontracted the electronics and firmware design (my main
business is an industrial design and mechanical engineering company)
so I couldn't comment on the code even if I wanted to!
We did, however, write the algorithms that were implemented but I am
reluctant to reveal too much as they are the key to the product. If it
helps, I can say that we found that two of the ways to make the
displayed check figure more usable were to only calculate it over part
of the stroke and to make adjustments for rate.