From: jim beam on 12 Mar 2010 00:52
On 03/11/2010 08:16 PM, clare(a)snyder.on.ca wrote:
> On Thu, 11 Mar 2010 19:20:26 -0800, jim beam<me(a)privacy.net> wrote:
>> On 03/11/2010 05:03 PM, clare(a)snyder.on.ca wrote:
>>> On Thu, 11 Mar 2010 16:04:31 -0500, clare(a)snyder.on.ca wrote:
>>>> On Wed, 10 Mar 2010 20:28:26 -0800, jim beam<me(a)privacy.net> wrote:
>>>>> On 03/09/2010 10:15 PM, Rodan wrote:
>>>>>> clare(a)snyder.on.ca wrote:
>>>>>> Toyota throttle has 2 hall effect sensors. The output of one tracks the
>>>>>> other but is offset. In other words, one starts at say, 0 volts, and the
>>>>>> other at, say 1 volt - and they increase in step with each other.
>>>>> how can that be true???
>>>>> hall effect sensors are used for gross position detection, not small
>>>>> scale linear deflections. they can be used for "wot" detection, but
>>>>> their ability to work over a wide positioning range is limited. that's
>>>>> why they're used in timing for things like crank position [rotational]
>>>>> sensors where you're counting pulse rates, not graduation functions.
>>>> You are wrong. Hall effect sensors are used instead of potentiometers
>>>> in all kinds of "variable output" controls including the throttles on
>>>> virtually all the electric scooters and e-bikes you see out there.
>>>> They are called "Ratiometric Linear Hall Effect Sensors.
>>> More research brings MORE interesting information.
>>> A "hall effect switch" is an adaptation of the basic "hall effect
>>> sensor", where a schmitt trigger and a comparator use the hall voltage
>>> to produce a "digital" signal.
>>> The basis of a hall effect sensor (the hall effect) is when current
>>> flows through a conductor in the presence of a magnetic field a
>>> voltage is produced at right angles to the current flow, and it varies
>>> with magnetic flux in both level and polarity.
>> at very close proximity. there is not a "good relationship" between
>> proximity and output for distance. thus, if you read you link again,
>> you'll see that those devices are used basically just as a pulse
>> counters, or on-off switch sensors, not proximity distance gauges. hall
>> effect potentiometers use this principle i think you'll find - they
>> count the number of pulses from origin, then electronically integrate,
>> not measure distance.
> Nope - they are used direcly as rotary controls like potentiometers,
> with on-chip amplifiers built in..Generally they are single ended - in
> other words using only N or only S magnetic polarity so the voltage is
> only positive or only negative - not using rail to rail dual power
> supplies. They are LINEAR, and actually extremely simple in concepr
> and application.
> The schmitt trigger type is as you say, strictly on and off, with
> designed in hysteresis. The fact that there IS hysteresis supports the
> fact that the output of the Hall "cell" itself IS linear, or at the
> very least variable.
ok, i guess i'm out of date.
>> this is an example of an appropriate integrator:
nomina rutrum rutrum
From: DC on 12 Mar 2010 01:04
<clare(a)snyder.on.ca> wrote in message
> When you have really sloppy conditions the "high viscosity water"
> causes the (wide) tires to "hydroplane" and braking causes the tire to
> skid immediately. Without ABS the "skid" gets a chance to scrape down
> through the slush and actually "find" pavement - allowing the vehicle
> to stop. <snip>
Couldn't agree more - the same mechanism can occur with gravel / shingle
roads where the pavement is "dirt". The layer of shingle acts as a lubricant
reducing braking force unless you can dig through it. ;)
From: David Skelton on 12 Mar 2010 09:02
"dizzy" <dizzy(a)nospam.invalid> wrote in message
> David Skelton wrote:
>>>>But, ABS does not
>>>>work so well in the very wet or icy conditions.
>>> Sure it does. It can't perform miracles, however.
>>No, it doesn't work so well in slippery conditions.
> I'd love to see you prove that statement. It's a fact beyond dispute
> that it aids stability and control...
>>In slippery conditions, it is much easier to lock all four wheels at once
>>with a stomp on the brake pedal. Then the ABS controller cannot detect
>>wheels turning at different speeds which is required to activate the ABS
> A) Does that really work? B) Why the HELL would you want to do that?
A) I've done it. Locked up all four, went sideways, released the foot brake
and steered into the slide, went the other way. We do not get much snow
here, nor ice, usually...
I have commented before about the (IMO) ridiculous width of tyres BMW put on
B) If some half blind deaf twerp steps out in front of your car, then it is
natural to try to stop quickly, isn't it ???
The day I got my first car (it was older than me), there was 3 inches of
snow on the ground. I had only had 13 driving lessons before passing the
test two weeks before (second attempt) so I did not have a lot of experience
on 4 wheels. I had a LOT of fun that night. But that was in the early 80's.
I'm more cautious now, and the cars cost a LOT more. ;-)
Another time, I was in a old car without ABS, I realised that because I was
not slowing after applying the brakes (all wheels locked), I was actually
pushing the pedal harder. Luckily, I became aware of what was happening and
released the pedal.
Maybe there should be " skidpan training" for all learners.
I personally think that all car drivers should spend a year or two on
motorcycles before driving a car to become more aware of surface condition
changes, and how that affects grip.
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From: cuhulin on 12 Mar 2010 10:36
In a lot of electronic things, there are such things as bad solder
joints.Ask anybody whom has repaired a lot of radios before, old radios
and even new radios, they will tell you.
There are many, many very old mechanical mechanisms which still are
working as good as new.
From: clare on 12 Mar 2010 16:55
On Fri, 12 Mar 2010 19:04:39 +1300, "DC" <chudley_del_(a)ihug.co.nz>
><clare(a)snyder.on.ca> wrote in message
>> When you have really sloppy conditions the "high viscosity water"
>> causes the (wide) tires to "hydroplane" and braking causes the tire to
>> skid immediately. Without ABS the "skid" gets a chance to scrape down
>> through the slush and actually "find" pavement - allowing the vehicle
>> to stop. <snip>
>Couldn't agree more - the same mechanism can occur with gravel / shingle
>roads where the pavement is "dirt". The layer of shingle acts as a lubricant
>reducing braking force unless you can dig through it. ;)
Loose sand on top af pavement too.