101 Ambulance stolen - Warrington

On Thu, 18 May 2006 15:46:53 +0100, Tom Woods
<[email protected]> wrote:

>>http://www.101fc.net/files/vids/digidash-20060225.wmv
>
>show off
>
>very nice though!. ive got a lilliput 7" screen for mine but i couldnt
>afford a little via 12v board so im using a small pc with an inverter.

Prolly a better idea in some senses to do so IMO.

>I was about to ask why it was running windows till i saw the titling
>at the end

The VMware session is fired on boot - I'm happy that I can just kill
Windoze like any other app

>so what are you actually using for the 'dash' bits?

Nothing yet - just running it as a car PC - for satnav and music etc.
I figured I really need to 'just do something you lazy sod' rather
than waiting until I had everything I need. I can add any interface
to it as I need to. The basic code is fine, but the IO has jet to be
decided - and what plugs into the IO, obviously


--
"We have gone from a world of concentrated knowledge and wisdom to one
of distributed ignorance. And we know and understand less while being
increasingly capable." Prof. Peter Cochrane, formerly of BT Labs
In memory of Brian {Hamilton Kelly} who logged off 15th September 2005

On Thu, 18 May 2006 23:13:31 +0100, Mother <"@ {mother} @"@101fc.net>
wrote:

>>so what are you actually using for the 'dash' bits?
>
>Nothing yet - just running it as a car PC - for satnav and music etc.
>I figured I really need to 'just do something you lazy sod' rather
>than waiting until I had everything I need. I can add any interface
>to it as I need to. The basic code is fine, but the IO has jet to be
>decided - and what plugs into the IO, obviously

Same idea here - except that i built the car pc 2.5 years ago or so,
but it never made it into the car as it works as a nice touchscreen
stereo which is ideal for when you have a big job on in the garage!

On Thu, 18 May 2006 22:35:52 +0100, Tim Hobbs wrote:

> Lee - anyone at your place know a supplier of calibrated odometers,

"Calibration" is dependant of the rolling radius of your tyres, so you
travel further and go faster if the pressures are low. B-)

> someone who can tell me the accuracy of mine?

"Measured miles" used to exist near most police forces traffic HQs for
checking their speedos etc. The one I used to know about, on the A69
Newcastle side of Hexham, disappeared a couple of years ago though.

Failing that, marker post on Motorways are 100m apart. You do the maths
for miles and how many you need to pass in how long for a given speed.

--
Cheers [email protected]
Dave. pam is missing e-mail

Dave Liquorice wrote:

> On Thu, 18 May 2006 22:35:52 +0100, Tim Hobbs wrote:
>
>> Lee - anyone at your place know a supplier of calibrated odometers,
>
> "Calibration" is dependant of the rolling radius of your tyres, so you
> travel further and go faster if the pressures are low. B-)
>
>> someone who can tell me the accuracy of mine?
>
> "Measured miles" used to exist near most police forces traffic HQs for
> checking their speedos etc. The one I used to know about, on the A69
> Newcastle side of Hexham, disappeared a couple of years ago though.
>
> Failing that, marker post on Motorways are 100m apart. You do the maths
> for miles and how many you need to pass in how long for a given speed.
>

Get a TomTom satnav and tell it to show speed - it's a 1 second average, but
if you average it over a few (Like 10) seconds you'll get a decent
calibration on your speedo.

P.

On Fri, 19 May 2006 09:45:59 GMT, "Paul S. Brown"
<[email protected]> wrote:

>Dave Liquorice wrote:
>
>> On Thu, 18 May 2006 22:35:52 +0100, Tim Hobbs wrote:
>>
>>> Lee - anyone at your place know a supplier of calibrated odometers,
>>
>> "Calibration" is dependant of the rolling radius of your tyres, so you
>> travel further and go faster if the pressures are low. B-)
>>
>>> someone who can tell me the accuracy of mine?
>>
>> "Measured miles" used to exist near most police forces traffic HQs for
>> checking their speedos etc. The one I used to know about, on the A69
>> Newcastle side of Hexham, disappeared a couple of years ago though.
>>
>> Failing that, marker post on Motorways are 100m apart. You do the maths
>> for miles and how many you need to pass in how long for a given speed.
>>
>
>Get a TomTom satnav and tell it to show speed - it's a 1 second average, but
>if you average it over a few (Like 10) seconds you'll get a decent
>calibration on your speedo.
>
>P.

All good, but not really what I'm after. I want to check the accuracy
of a device over about 1000 miles, on a mixture of roads. Currently I
have a discrepancy of about 8% between the box and the Navara (the
Navara being higher). What I don't know is whether one is low, one is
high or a bit of both.

Rolling radius of the wheels can be maintained over that distance -
wear will be negligible. The 1000 miles will be covered in 48 hours
quite easily so pressures can be held static (I've just passed 5000
miles and have had the truck since end of March).



--

Tim Hobbs

'58 Series 2 88" aka "Stig"
'03 Volvo V70
'06 Nissan Navara aka "The Truck"

On or around Fri, 19 May 2006 10:56:58 +0100, Tim Hobbs <[email protected]>
enlightened us thusly:

>
>All good, but not really what I'm after. I want to check the accuracy
>of a device over about 1000 miles, on a mixture of roads. Currently I
>have a discrepancy of about 8% between the box and the Navara (the
>Navara being higher). What I don't know is whether one is low, one is
>high or a bit of both.
>
>Rolling radius of the wheels can be maintained over that distance -
>wear will be negligible. The 1000 miles will be covered in 48 hours
>quite easily so pressures can be held static (I've just passed 5000
>miles and have had the truck since end of March).

the motorway posts have numbers on 'em too - you could pick a suitable bit
of motorway driving, hit the trip meter as you pass a post with a known
number and then drive e.g. 100km or something (or more, if you're going
further on the same motorway) and then note the reading. In fact, for
better accuracy, you could pull onto the hard shoulder, park beside a post,
zero the trip, then drive, then pull onto the hard shoulder by a post near
your exit point, and note the mileage on the truck milometer as compared to
the distance on the m-way markers.

if you can do about 200Km on the same road, the measured distance should be
accurate to well under 0.1% - the markers are 100m apart, so over 200Km the
distance between markers is 0.5% and even if they markers are not measured
with pinpoint accuracy, on that sort of a scale you can get well under one
tenth of a scale division[1] accuracy. I'd have thought that would get you
close enough, really. you should be able easily (especially if you repeat
the exercise on several different motorways) to get the accuracy down to
0.05% by suitable statistical analysis, maybe better than that. You can
position the truck within a metre of the marker post, I reckon, easily
enough if you stop on the hard shoulder beside it...



[1] cue discussion about accuracy of readings: when I was doing physics in
uni, the bloke teaching us about experimental technique held that if you
have a scale with divisions n, and measure a quantity x using said scale,
your accuracy was always +/-(n). I held than in general you could easily
get +/-(0.5n). There are special cases where this doesn't apply, but as a
general rule, your starting point will be chosen to match a scale division
to high(ish) accuracy.

Suppose, for example, you measure a steel bar, which has an actual length of
123.4cm using a ruler with 1cm divisions. You choose to put the ruler so
that one end of it (or a chosen scale mark) lines up as closely as you can
get it to one end of the bar. you then judge the length by looking at the
other end, which falls between 123 and 124 on the scale. In this case, it
falls somewhere approximately half-way between the marks, and therefore you
can quote the measurement as 123.5 +/-0.5cm. The lecturer bloke was adamant
that you'd quote it as 123 +/-1cm. If the reading was obviously a lot
nearer to 123 than to 124, you'd quote 123.0+/-0.5cm. You can argue that
you have an error at both ends of the measurement but for the vast majority
of measurements, you wouldn't do that, you'd move the scale and reduce the
error at the starting end to a minimum. Even if you can't actually do that,
for almost all scales, it's possible to judge to the nearest half-division
by eye.
--
Austin Shackles. www.ddol-las.net my opinions are just that
"You praise the firm restraint with which they write -_
I'm with you there, of course: They use the snaffle and the bit
alright, but where's the bloody horse? - Roy Campbell (1902-1957)

Austin Shackles <[email protected]> uttered summat worrerz
funny about:
> the motorway posts have numbers on 'em too - you could pick a
> suitable bit of motorway driving, hit the trip meter as you pass a
> post with a known number and then drive e.g. 100km or something (or
> more, if you're going further on the same motorway) and then note the
> reading. In fact, for better accuracy, you could pull onto the hard
> shoulder, park beside a post, zero the trip, then drive, then pull
> onto the hard shoulder by a post near your exit point, and note the
> mileage on the truck milometer as compared to the distance on the
> m-way markers.
>
> if you can do about 200Km on the same road, the measured distance
> should be accurate to well under 0.1% - the markers are 100m apart,
> so over 200Km the distance between markers is 0.5% and even if they
> markers are not measured with pinpoint accuracy, on that sort of a
> scale you can get well under one tenth of a scale division[1]
> accuracy. I'd have thought that would get you close enough, really.
> you should be able easily (especially if you repeat the exercise on
> several different motorways) to get the accuracy down to
> 0.05% by suitable statistical analysis, maybe better than that. You
> can position the truck within a metre of the marker post, I reckon,
> easily enough if you stop on the hard shoulder beside it...
>
>
>
> [1] cue discussion about accuracy of readings: when I was doing
> physics in uni, the bloke teaching us about experimental technique
> held that if you have a scale with divisions n, and measure a
> quantity x using said scale, your accuracy was always +/-(n). I held
> than in general you could easily get +/-(0.5n). There are special
> cases where this doesn't apply, but as a general rule, your starting
> point will be chosen to match a scale division to high(ish) accuracy.
>
> Suppose, for example, you measure a steel bar, which has an actual
> length of 123.4cm using a ruler with 1cm divisions. You choose to
> put the ruler so that one end of it (or a chosen scale mark) lines up
> as closely as you can get it to one end of the bar. you then judge
> the length by looking at the other end, which falls between 123 and
> 124 on the scale. In this case, it falls somewhere approximately
> half-way between the marks, and therefore you can quote the
> measurement as 123.5 +/-0.5cm. The lecturer bloke was adamant that
> you'd quote it as 123 +/-1cm. If the reading was obviously a lot
> nearer to 123 than to 124, you'd quote 123.0+/-0.5cm. You can argue
> that you have an error at both ends of the measurement but for the
> vast majority of measurements, you wouldn't do that, you'd move the
> scale and reduce the error at the starting end to a minimum. Even if
> you can't actually do that, for almost all scales, it's possible to
> judge to the nearest half-division by eye.

I'll do some digging here but basically those vehicles we use are sent away
and come back with a calibrated Speedo and certificate, theres also a
sticker and serial number on the dash.
We then run checks on the vehicle either weekly or certainly prior to any
operation to target hot spot areas. These boil down to driving a measured
mile (marked on various road surface in the county with a white rectangle in
staffs - usually Dual carriageways, not round circle markers though they are
just used for VASCAR) at 60mph against a stop watch. Also running through
the laser at both 30 and 60mph to then check against laser and vehicle. The
lasers are seperately calibrated and tested.

I'll find out te address for you.

Lee

I walked a measured mile, and it took me 14 and a half minutes, and then I
set my pedometer by it, and discovered more recently I had covered a mile in
12 minutes and that was not a straight mile downhill like the one I used for
calibration either and included crossing roads wierd to say the least

I walk with a cane and a painful back and all

--
Larry
Series 3 rust and holes


"Dave Liquorice" <[email protected]> wrote in message
news:[email protected]...
> On Thu, 18 May 2006 22:35:52 +0100, Tim Hobbs wrote:
>
> "Measured miles" used to exist near most police forces traffic HQs for
> checking their speedos etc. The one I used to know about, on the A69
> Newcastle side of Hexham, disappeared a couple of years ago though.
>
> Failing that, marker post on Motorways are 100m apart. You do the maths
> for miles and how many you need to pass in how long for a given speed.
>
> --
> Cheers [email protected]
> Dave. pam is missing e-mail
>
>
>

Not that I believe a word of that, its like those speed warning signs, you
have to take into account the curvature of the earth the tides, the
influence of cosmic rays, the density of rubber, the astrological alignment
and whether you were driving along a ley line or not.

You'll be telling me next they have solved the problem of longitude and
there is no bermuda triangle


--
Larry
Series 3 rust and holes



"Lee_D" <[email protected]> wrote in message
news:[email protected]...
> Austin Shackles <[email protected]> uttered summat worrerz
> funny about:
>>
> I'll do some digging here but basically those vehicles we use are sent
away
> and come back with a calibrated Speedo and certificate, theres also a
> sticker and serial number on the dash.
> We then run checks on the vehicle either weekly or certainly prior to any
> operation to target hot spot areas. These boil down to driving a measured
> mile (marked on various road surface in the county with a white rectangle
in
> staffs - usually Dual carriageways, not round circle markers though they
are
> just used for VASCAR) at 60mph against a stop watch. Also running through
> the laser at both 30 and 60mph to then check against laser and vehicle.
The
> lasers are seperately calibrated and tested.
>
> I'll find out te address for you.
>
> Lee
>
>

Larry wrote:

|| <snip> I had
|| covered a mile in 12 minutes

A mile in 12 minutes? That's *jogging*.

--
Rich
==============================

I don't approve of signatures, so I don't have one.