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Date: Apr 11, 2008 09:20
I have no idea what they're called, the LED signs in some bus stops
that tell you how long the busses are supposed to be, my question is,
how do they work? how do they update?
A few times I've seen that my bus is due next in a couple of minutes
but it just doesn't arrive, several later busses come and then it
vanishes off the sign, abducted by aliens?
Then there are the times I've seen my bus is due in 10 minutes and
decided that instead of standing in the cold I'll walk to the next or
previous stop only for it to come sailing past when I'm mid-way
between stops.
And how many seconds are in a London Transport minute anyway? 90 at
least.
Obviously the system is not perfect (no system is) but if I knew what
made it tick I may be better equipped for getting around.
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Author: Mizter TMizter T Date: Apr 11, 2008 09:48
On 11 Apr, 17:20, MarkVarley - MVP softhome.net>
wrote:
> I have no idea what they're called, the LED signs in some bus stops
> that tell you how long the busses are supposed to be, my question is,
> how do they work? how do they update?
>
> A few times I've...
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Author: Paul TerryPaul Terry Date: Apr 11, 2008 09:50
In message 4ax.com>, MarkVarley -
MVP softhome.net> writes
>I have no idea what they're called, the LED signs in some bus stops
>that tell you how long the busses are supposed to be, my question is,
>how do they work? how do they update?
The current system, called Countdown, is fairly primitive. When a bus
passes a fixed point (with a large bar-code) earlier along the route,
the system simply adds the standard time it takes to get from that fixed
point to the bus stop at which you are waiting. If the bus subsequently
gets delayed, it knows nothing about it. Equally, if the bus is diverted
or is too far from the curbside to trigger the reader, or if it is
overtaking another bus (or any large vehicle) as it passes the bar-code,
the system know nothing about it.
The Countdown system is currently being replaced by a rather better,
GPS-based system.
--
Paul Terry
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Author: MIGMIG Date: Apr 11, 2008 09:56
On Apr 11, 5:48 pm, Mizter T gmail.com> wrote:> On 11 Apr, 17:20, MarkVarley - MVP softhome.net>
> wrote:
>
>
>
>
>>> I have no idea what they're called, the LED signs in some bus stops
>> that tell you how long the busses are supposed to be, my question is,
>> how do they work? how do they update?
>
>> A few times I've seen that my bus is due next in a couple of minutes
>> but it just doesn't arrive, several later busses come and then it
>> vanishes off the sign, abducted by aliens?
>
>> Then there are the times I've seen my bus is due in 10 minutes and
>> decided that instead of standing in the cold I'll walk to the next or
>> previous stop only for it to come sailing past when I'm mid-way
>> between stops. ...
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Author: Tom AndersonTom Anderson Date: Apr 11, 2008 10:52
On Fri, 11 Apr 2008, Mizter T wrote:
> On 11 Apr, 17:20, MarkVarley - MVP softhome.net>
> wrote:
>>> I have no idea what they're called, the LED signs in some bus stops
>> that tell you how long the busses are supposed to be, my question is,
>> how do they work? how do they update?
>
> The system is called Countdown, and as part of the iBus project it is
> set to become much more reliable and accurate.
Which is a roundabout way of saying that the present system is not very
reliable or accurate :P.
As another poster pointed out, the present system is rather Heath-Robinson
and failure-prone. It was, though, the best that could be done with the
technology of the time it was implemented. Frustrating as it is, it's
better than nothing.
tom
--
Ed editor textorum probatissimus est -- Cicero, De officiis IV.7
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Author: Tom AndersonTom Anderson Date: Apr 11, 2008 11:04
On Fri, 11 Apr 2008, MIG wrote:
> On Apr 11, 5:48 pm, Mizter T gmail.com> wrote:>> On 11 Apr, 17:20, MarkVarley - MVP softhome.net>
>> wrote:
>>>>> I have no idea what they're called, the LED signs in some bus stops
>>> that tell you how long the busses are supposed to be, my question is,
>>> how do they work? how do they update?
>>
>> The system is called Countdown, and as part of the iBus project it is
>> set to become much more reliable and accurate.
>
> I wonder if it means more reliable in terms of whether it breaks down
> or reliable in terms of the content, which must be down to where the
> locations of the bus-detectors rather than the system that passes
> information to the punters.
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Author: MIGMIG Date: Apr 11, 2008 11:22
On Apr 11, 7:04 pm, Tom Anderson wrote:
> On Fri, 11 Apr 2008, MIG wrote:
>> On Apr 11, 5:48 pm, Mizter T gmail.com> wrote:>>> On 11 Apr, 17:20, MarkVarley - MVP softhome.net>
>>> wrote:>
>>>> I have no idea what they're called, the LED signs in some bus stops
>>>> that tell you how long the busses are supposed to be, my question is,
>>>> how do they work? how do they update?
>
>>> The system is called Countdown, and as part of the iBus project it is
>>> set to become much more reliable and accurate.
>
>> I wonder if it means more reliable in terms of whether it breaks down
>> or reliable in terms of the content, which must be down to where the
>> locations of the bus-detectors rather than the system that passes
>> information to the punters.
>
> The new system won't use bus detectors, it'll have a GPS unit on each bus
> which radios its position back to base (by GPRS?). That gives it higher ...
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Author: MIGMIG Date: Apr 11, 2008 11:26
On Apr 11, 6:52 pm, Tom Anderson wrote:
> On Fri, 11 Apr 2008, Mizter T wrote:
>> On 11 Apr, 17:20, MarkVarley - MVP softhome.net>
>> wrote:>
>>> I have no idea what they're called, the LED signs in some bus stops
>>> that tell you how long the busses are supposed to be, my question is,
>>> how do they work? how do they update?
>
>> The system is called Countdown, and as part of the iBus project it is
>> set to become much more reliable and accurate.
>
> Which is a roundabout way of saying that the present system is not very
> reliable or accurate :P.
>
> As another poster pointed out, the present system is rather Heath-Robinson
> and failure-prone. It was, though, the best that could be done with the
> technology of the time it was implemented...
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Author: Mr ThantMr Thant Date: Apr 11, 2008 13:54
On 11 Apr, 19:04, Tom Anderson wrote:
> Provided that the bus can get good GPS and GPRS signals. GPS is
> notoriously inaccurate in built-up areas, as buildings block lines of
> sight to the satellites, and introduce reflections which confuse the
> receiver (like ghosting on the telly). I wonder what they're doing to deal
> with this?
I've read a TfL paper that I can't find right now that found it to be
surprisingly accurate, something like dead on 98%% of the time.
Presumably to do with being aerial mounting a large antenna on the bus
roof where it has a good view of the sky, rather than the tiny
internal one in consumer gear that gets blocked by the car roof.
Is there a way to tell if a bus is using iBus data or Countdown. Have
any iBus-based displays even been deployed yet?
U
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