Subject:
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Re: Sensor Sampling; Progress?
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Newsgroups:
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lugnet.robotics.rcx.legos
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Date:
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Sun, 19 Jan 2003 00:34:55 GMT
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Viewed:
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3235 times
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"John Barnes" <barnes@sensors.com> wrote:
> I note that in your description of the active sensor power and sample
> timing, you give the impression that you are only sampling one sensor per
> power interruption. Is this correct?
Yes.
> Does this mean that you can interrupt the power to each sensor • individually
> in the RCX?
That's right.
> In which case this is a good thing since the average power to
> the sensors will meet or exceed that provided by the standard firmware.
I agree. With the current firmware, power gets cut off to all
3 sensors for ~85us (sometimes longer). With the scheme
I mentioned, power would be cut to only one sensor for
~25us. The sample rate could be adjusted anywhere from
8 Hz to 6 KHz. BrickOS already works like this but the
sample rate is pegged at 6.7 KHz so the power duty cycle
isn't all that good.
> Some sensors are right on the ragged edge of providing enough power • storage
> to "flywheel" over these interruptions and so I am concerned that these
> sensors may fail if starved of power.
By reducing the sample rate, the power duty cycle would
increase. As long as the sensor could take the ~25 us
hit and recover before the next sample, you'd be in great
shape!
Of course, you could always put batteries in the sensor... ;-)
Mark (making a quick exit...)
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Message has 1 Reply:
 | | Re: Sensor Sampling; Progress?
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| The Lego firmware cuts power for about 200uS, with a period of 3mS. So most sensors have to have enough capacitor based power storage for the full 200uS and be able to run on about 93% duty cycle. (The rotation sensor is one of the devices on the (...) (22 years ago, 19-Jan-03, to lugnet.robotics.rcx.legos)
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Message is in Reply To:
| | Re: Sensor Sampling; Progress?
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| I have been following this thread with great interest for two reasons. One day, someone will be persuaded to provide me with direct help and assistance in getting BrickOS running on my laptop - perhaps at BW or BF. I have built quite a few prototype (...) (22 years ago, 18-Jan-03, to lugnet.robotics.rcx.legos)
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