Cateye cordless 7 accuracy

[Brian Wakem]

"Richard Bates" <[email protected]> wrote in message
news:[email protected]...
> On Thu, 06 Jan 2005 20:40:18 +0000, Brian Wakem <[email protected]> wrote:
>
> >I have a couple of regular off-road routes that I do at night on my
mountain
> >bike. Bizarrely the distance of each course seems to be getting
> >progressively shorter.
> >Anybody have any clue as to what might be going on here?
>
> Are you travelling at or near the speed of light?


I'm no physicist, but wouldn't the distance remain constant at any speed and
the
time taken relative to a stationary watch would be different?


--
Brian Wakem

 

[Paul - xxx]

Brian Wakem composed the following;:
> "Paul - ***" <[email protected]> wrote in message

>> That's about, rough approximation, a 0.1 % difference in distance, over
>> 17 miles, which is bloody good accuracy for a cycle computer, I'd say.
>
> I make it a 3% difference.
>

I didn't calculate it ..

>> I'd say similar to the first route, again bugger all change in percentage
>> terms of the whole distance covered, and such a small distance change
> might
>> easily be explained as above.
>>
>> You don't say how long you've been travelling the route, but if you've
> only
>> recently started 'logging' it, then maybe, over a much longer timeframe,
> the
>> distance will tend to settle down to an optimum level, but that might
>> take weeks or more.
>
> All these times were logged between Nov 22nd and Jan 6th.

So you've done route one five times and route two thirteen times in a little
over a month and get a (your calculation) 3% difference. When you look at
the distances posted they don't all get less, some distances are higher than
the preceeding one, which again suggests slight route variation. As an
example, maybe some days you go round a few puddles, other days there aren't
any puddles so you go straight through where the puddle would be.

I'd suggest you're being a little picky and don't have a long enough
timescale or number of journeys to worry about yet. Let's face it the
general route you take might be the same, but the route the tyres take is
never identical, so variations, especially over that sort of distance and of
the magnitude you're experiencing, are to be expected.


--
Paul ...
http://www.4x4prejudice.org/index.php
(8(!) Homer Rules ...
"A ****** is a ******, no matter what mode of transport they're using."

 

[David Martin]

On 7/1/05 10:57 am, in article [email protected], "Brian Wakem"
<[email protected]> wrote:

>> You are going faster so less low speed wobble.
>
>
> Faster yes, but I wasn't going that slow enough to wobble to start with.
>

You are always wobbling. It is how you balance. (Dons flameproof suit).
At high speeds the wobble is less than lower speeds.

...d

 

[Arthur Clune]

Brian Wakem <[email protected]> wrote:

: All these times were logged between Nov 22nd and Jan 6th.

I had a Cateye Cordless 7 and ditched it for being ****. Regardless of
position of sensors and with new batterys it would consistently loose the
odd signal. So if I was cycling at a constant 20mph, the speed would
read

20, 20, 20 15, 20, 20, 20, 20, 20, 13, 20 etc

which corresponding affects on the average time and distance covered

--
Arthur Clune PGP/GPG Key: http://www.clune.org/pubkey.txt
It is better to light a candle than to curse the darkness

 

[Brian Wakem]

"Arthur Clune" <[email protected]> wrote in message
news:[email protected]...
> Brian Wakem <[email protected]> wrote:
>
> : All these times were logged between Nov 22nd and Jan 6th.
>
> I had a Cateye Cordless 7 and ditched it for being ****. Regardless of
> position of sensors and with new batterys it would consistently loose the
> odd signal. So if I was cycling at a constant 20mph, the speed would
> read
>
> 20, 20, 20 15, 20, 20, 20, 20, 20, 13, 20 etc
>
> which corresponding affects on the average time and distance covered

hmmm. I only really ride the mountain bike at night so I don't get to see
what the speedo says. Maybe I'll do some test runs in daytime.

--
Brian Wakem

 

[DavidR]

"MSeries" <[email protected]> wrote
> Brian Wakem wrote:

>> I have a couple of regular off-road routes that I do at night on my
>> mountain
>> bike. Bizarrely the distance of each course seems to be getting
>> progressively shorter.

> I don't think these things are guarenteed to be accurate to that amount
> so it wouldn't surprise me if thats just the way it is inside the
> devices. My best gusess would be the performance of the device including
> its batteries changing with the temperature/humidity etc.

It either counts a pulse or it doesn't. The software converts the pulse
count to a distance value in the display and software is neither
temperature or humidity dependant.

As long as pulses reach the unit, it is always as accurate as the
calibration value you enter.

 

[MSeries]

DavidR wrote:
> "MSeries" <[email protected]> wrote
>
>>Brian Wakem wrote:
>
>
>>>I have a couple of regular off-road routes that I do at night on my
>>>mountain
>>>bike. Bizarrely the distance of each course seems to be getting
>>>progressively shorter.
>
>
>>I don't think these things are guarenteed to be accurate to that amount
>>so it wouldn't surprise me if thats just the way it is inside the
>>devices. My best gusess would be the performance of the device including
>>its batteries changing with the temperature/humidity etc.
>
>
> It either counts a pulse or it doesn't. The software converts the pulse
> count to a distance value in the display and software is neither
> temperature or humidity dependant.
>
> As long as pulses reach the unit, it is always as accurate as the
> calibration value you enter.
>
>
as I said my best guess. You seem to know better.

 

[Clive George]

"DavidR" <nospam_a@t_nospam.com> wrote in message
news:[email protected]...
> "MSeries" <[email protected]> wrote
> > Brian Wakem wrote:
>
> >> I have a couple of regular off-road routes that I do at night on my
> >> mountain
> >> bike. Bizarrely the distance of each course seems to be getting
> >> progressively shorter.
>
> > I don't think these things are guarenteed to be accurate to that amount
> > so it wouldn't surprise me if thats just the way it is inside the
> > devices. My best gusess would be the performance of the device including
> > its batteries changing with the temperature/humidity etc.
>
> It either counts a pulse or it doesn't. The software converts the pulse
> count to a distance value in the display and software is neither
> temperature or humidity dependant.
>
> As long as pulses reach the unit, it is always as accurate as the
> calibration value you enter.

I reckon pulses are being missed.

cheers,
clive

 

[Clive George]

"DavidR" <nospam_a@t_nospam.com> wrote in message
news:[email protected]...
> "MSeries" <[email protected]> wrote
> > Brian Wakem wrote:
>
> >> I have a couple of regular off-road routes that I do at night on my
> >> mountain
> >> bike. Bizarrely the distance of each course seems to be getting
> >> progressively shorter.
>
> > I don't think these things are guarenteed to be accurate to that amount
> > so it wouldn't surprise me if thats just the way it is inside the
> > devices. My best gusess would be the performance of the device including
> > its batteries changing with the temperature/humidity etc.
>
> It either counts a pulse or it doesn't. The software converts the pulse
> count to a distance value in the display and software is neither
> temperature or humidity dependant.
>
> As long as pulses reach the unit, it is always as accurate as the
> calibration value you enter.

I reckon pulses are being missed.

cheers,
clive

 

[Mark Thompson]

> I don't think these things are guarenteed to be accurate to that
> amount

All it's got to do is measure clicks - not complicated and as accurate as a
clicky thing in the wheel surely?

The difference between the distances is fairly significant. As all the
computer has to do is count the clicks it must be missing clicks out,
losing the odd click in transmission, or the wheel circumference has
changed. Oh, or you're taking shortcuts. The only clever bit about the
computers is the wireless thingy. My best guess would be that is where the
dropped 'clicks' are.

Possibly replacing the batttery in the transmitter might help it out - the
batteries included with products are rarely in the best condition, and the
battery in my transmitter didn't last past 750 miles-ish. Also, making
sure that the transmitter and receiver are on the same side of the
handlebars and in the optimum position could help.

It's either that or the shortcut option. I still think you should eat more
pies just in case it is a weight thing.

 

[Mark Tranchant]

Mark Thompson wrote:

> The difference between the distances is fairly significant. As all the
> computer has to do is count the clicks it must be missing clicks out,
> losing the odd click in transmission, or the wheel circumference has
> changed. Oh, or you're taking shortcuts. The only clever bit about the
> computers is the wireless thingy. My best guess would be that is where the
> dropped 'clicks' are.

Sometimes wireless computers can add clicks, too. My VDO Cytec C10+ is
usually very accurate, but occasionally reports crazy numbers like
150mph - I never exceed about 95mph usually. ;-)

Using my front LED backup light in flashing mode adds about 40mph to my
speed, even when stationary.

--
Mark.
http://tranchant.plus.com/

 

[MSeries]

Mark Thompson wrote:
>>I don't think these things are guarenteed to be accurate to that
>>amount
>
>
> All it's got to do is measure clicks - not complicated and as accurate as a
> clicky thing in the wheel surely?
>

It had to generate the clicks in the sender unit too. Unlike a wired one
which detects a voltage drop as the magnet opens a switch. Unlike a
mechanical devide where the click just happens. I suspect the generation
of the clicks is at fault, perhaps not quick enough sometimes, due to
what I said before.

All pure speculation on my part I have never owned a wireless computer.

 

[MSeries]

DavidR wrote:

>
> It either counts a pulse or it doesn't. The software converts the pulse
> count to a distance value in the display and software is neither
> temperature or humidity dependant.
>
> As long as pulses reach the unit, it is always as accurate as the
> calibration value you enter.
>
>

Provided the pulses are being generated properly, I have not assumed
this to be the case.

 

[David Lowther]

"Brian Wakem" <[email protected]> wrote in message
news:[email protected]...
>I have a couple of regular off-road routes that I do at night on my
>mountain
> bike. Bizarrely the distance of each course seems to be getting
> progressively shorter.

FWIW: I've had mine a few years and the distance reading is very repeatable.
For example on a favourite short road ride, I consistently get 10.16 +/-
0.01 miles. I've done it 10's of times. The only time it changes, and then
only by 0.02 miles or so, is when I notice the tyres are a bit soft and pump
them up.

--
Dave Lowther
E-mail [email protected]
Drop the rconham to reply by e-mail.
Web http://www.dlowther.demon.co.uk/local.htm

 

[Simon Brooke]

in message <[email protected]>, MSeries
('[email protected]') wrote:

> Mark Thompson wrote:
>>>I don't think these things are guarenteed to be accurate to that
>>>amount
>>
>>
>> All it's got to do is measure clicks - not complicated and as
>> accurate as a clicky thing in the wheel surely?
>>
>
> It had to generate the clicks in the sender unit too. Unlike a wired
> one which detects a voltage drop as the magnet opens a switch. Unlike
> a mechanical devide where the click just happens. I suspect the
> generation of the clicks is at fault, perhaps not quick enough
> sometimes, due to what I said before.
>
> All pure speculation on my part I have never owned a wireless
> computer.

My specialized one got its first new batteries this year (the RX end
battery had died but I replaced the TX battery at the same time on the
precautionary principle). It's eight years old and has never missed a
beat. There's absolutely nothing wrong in principle with wireless
computers.

--
[email protected] (Simon Brooke) http://www.jasmine.org.uk/~simon/

;; All in all you're just another nick in the ball
-- Think Droid

 

[MSeries]

Simon Brooke wrote:
> in message <[email protected]>, MSeries
> ('[email protected]') wrote:
>
>
>>Mark Thompson wrote:
>>
>>>>I don't think these things are guarenteed to be accurate to that
>>>>amount
>>>
>>>
>>>All it's got to do is measure clicks - not complicated and as
>>>accurate as a clicky thing in the wheel surely?
>>>
>>
>>It had to generate the clicks in the sender unit too. Unlike a wired
>>one which detects a voltage drop as the magnet opens a switch. Unlike
>>a mechanical devide where the click just happens. I suspect the
>>generation of the clicks is at fault, perhaps not quick enough
>>sometimes, due to what I said before.
>>
>>All pure speculation on my part I have never owned a wireless
>>computer.
>
>
> My specialized one got its first new batteries this year (the RX end
> battery had died but I replaced the TX battery at the same time on the
> precautionary principle). It's eight years old and has never missed a
> beat. There's absolutely nothing wrong in principle with wireless
> computers.
>

I know but the OP doesn't seem content with his..

 

[MSeries]

Simon Brooke wrote:
> in message <[email protected]>, MSeries
> ('[email protected]') wrote:
>
>
>>Mark Thompson wrote:
>>
>>>>I don't think these things are guarenteed to be accurate to that
>>>>amount
>>>
>>>
>>>All it's got to do is measure clicks - not complicated and as
>>>accurate as a clicky thing in the wheel surely?
>>>
>>
>>It had to generate the clicks in the sender unit too. Unlike a wired
>>one which detects a voltage drop as the magnet opens a switch. Unlike
>>a mechanical devide where the click just happens. I suspect the
>>generation of the clicks is at fault, perhaps not quick enough
>>sometimes, due to what I said before.
>>
>>All pure speculation on my part I have never owned a wireless
>>computer.
>
>
> My specialized one got its first new batteries this year (the RX end
> battery had died but I replaced the TX battery at the same time on the
> precautionary principle). It's eight years old and has never missed a
> beat. There's absolutely nothing wrong in principle with wireless
> computers.
>

I know but the OP doesn't seem content with his..

 

[Chris Malcolm]

Simon Brooke <[email protected]> writes:

>in message <[email protected]>, MSeries
>('[email protected]') wrote:

>> Mark Thompson wrote:
>>>>I don't think these things are guarenteed to be accurate to that
>>>>amount

>>> All it's got to do is measure clicks - not complicated and as
>>> accurate as a clicky thing in the wheel surely?

>> It had to generate the clicks in the sender unit too. Unlike a wired
>> one which detects a voltage drop as the magnet opens a switch. Unlike
>> a mechanical devide where the click just happens. I suspect the
>> generation of the clicks is at fault, perhaps not quick enough
>> sometimes, due to what I said before.
>>
>> All pure speculation on my part I have never owned a wireless
>> computer.

>My specialized one got its first new batteries this year (the RX end
>battery had died but I replaced the TX battery at the same time on the
>precautionary principle). It's eight years old and has never missed a
>beat. There's absolutely nothing wrong in principle with wireless
>computers.

There's nothing wrong with anything which works properly. The problem
is that this one doesn't. In principle anything which doesn't work
properly is unsatisfactory.

The security of radio receivers against interference usually goes down
as battery voltage diminishes. If interference is causing pulse loss,
then gradually weakening batteries, whether due to age or lowering
temperatures, would cause gradually increasing pulse loss, and
therefore apparent gradual shortening of distance.
--
Chris Malcolm [email protected] +44 (0)131 651 3445 DoD #205
IPAB, Informatics, JCMB, King's Buildings, Edinburgh, EH9 3JZ, UK
[http://www.dai.ed.ac.uk/homes/cam/]

 

[MSeries]

Chris Malcolm wrote:
> Simon Brooke <[email protected]> writes:
>
>
>>in message <[email protected]>, MSeries
>>('[email protected]') wrote:
>
>
>>>Mark Thompson wrote:
>>>
>>>>>I don't think these things are guarenteed to be accurate to that
>>>>>amount
>
>
>>>>All it's got to do is measure clicks - not complicated and as
>>>>accurate as a clicky thing in the wheel surely?
>
>
>>>It had to generate the clicks in the sender unit too. Unlike a wired
>>>one which detects a voltage drop as the magnet opens a switch. Unlike
>>>a mechanical devide where the click just happens. I suspect the
>>>generation of the clicks is at fault, perhaps not quick enough
>>>sometimes, due to what I said before.
>>>
>>>All pure speculation on my part I have never owned a wireless
>>>computer.
>
>
>>My specialized one got its first new batteries this year (the RX end
>>battery had died but I replaced the TX battery at the same time on the
>>precautionary principle). It's eight years old and has never missed a
>>beat. There's absolutely nothing wrong in principle with wireless
>>computers.
>
>
> There's nothing wrong with anything which works properly. The problem
> is that this one doesn't. In principle anything which doesn't work
> properly is unsatisfactory.
>
> The security of radio receivers against interference usually goes down
> as battery voltage diminishes. If interference is causing pulse loss,
> then gradually weakening batteries, whether due to age or lowering
> temperatures, would cause gradually increasing pulse loss, and
> therefore apparent gradual shortening of distance.
> --
> Chris Malcolm [email protected] +44 (0)131 651 3445 DoD #205
> IPAB, Informatics, JCMB, King's Buildings, Edinburgh, EH9 3JZ, UK
> [http://www.dai.ed.ac.uk/homes/cam/]
>
Thats what I said.

 

[Arthur Clune]

Simon Brooke <[email protected]> wrote:

: beat. There's absolutely nothing wrong in principle with wireless
: computers.

Sure. In principle. Just that the one I brought was a complete steaming
pile of turd.

Arthur.

--
Arthur Clune PGP/GPG Key: http://www.clune.org/pubkey.txt
It is better to light a candle than to curse the darkness