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 Robotics / RCX / 1128
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Subject: 
Re: light sensor multiplexer
Newsgroups: 
lugnet.robotics.rcx
Date: 
Wed, 21 Mar 2001 19:29:43 GMT
Viewed: 
1628 times
  
In lugnet.robotics.rcx, Rainer Balzerowski writes:
hi  Rainer
Now adress second sharp -> 10ms LOW 10ms HIGH 10ms LOW -> 30 ms + 53ms for
reading second sharp. 50ms + 53 ms for third. Together 249ms.
Do I make a mistake ?

This is not true since you need to maximum of 60ms after that time out
occurs in microconterolor and it chanes the sensor.
yes that is true that it is slow for your application.
I maid it from removing limitation on sensors. where you have sensors which
you need to check conditionaly ( not intended for fast switching)
like if you have experimet say you need to get distance Vs ambient light
plot then this can be very usefull.

I am not saying that you have to use it!:-)
Just trying to showother what I have made. since no one has made something
like this ( not known to me at list)
any way bye  and regards.

Nitin
Hi Nitin,

In lugnet.robotics.rcx, Nitin Patil writes:
Hi Rainer,

I do not understand quite your point about timing. Regarding to
power sharp takes much more than what your RCX can give ( my measuremants
show that RCX gives RMS current of )15 mA only this is not going to drive
your sharp at all.

Yes, sadly but true. That's why I have to use a battery anyway. (Or an
output, but I would save it for other tasks.)

Regarding timing you need one pulse to three pulses  to chose and transfer
the sensor. once you have done it you can be there on that sensor as long as
you wish. ( it looks like to me that you have( or I have ) little
misunderstanding on what I(or you ) do.

I understand. I should have explained what i'm doing with the sharps, sorry.
I have a task running, that continuously read the values of the three sharps
(in a cycle) and store them in global variables. This way I have valid
values from my sharps all the time (some 10ms old).

This timing is for (theoreticaly) use with Sharp GP2D12 only !!
With your solution I have to adress first sharp with 10 ms LOW (as described
on your website), then have to wait (worst case of course) 53 ms for first
valid data from the first sharp.
Now adress second sharp -> 10ms LOW 10ms HIGH 10ms LOW -> 30 ms + 53ms for
reading second sharp. 50ms + 53 ms for third. Together 249ms.
Do I make a mistake ?

Regarding Gasperis circuit. first of all it is NOT random selection of
sensors. and you need a referance channel. another in not very effecient in
power since it have lot of components. I have single microcontrolor running
at 4Mhz and if the power requirements are stringents I can run it at lower
speed to get it working at extremely low power.

Now adress second sharp -> 10ms LOW 10ms HIGH 10ms LOW -> 30 ms + 53ms for
reading second sharp. 50ms + 53 ms for third. Together 249ms.
Do I make a mistake ?

Best wishes

Rainer



Message is in Reply To:
  Re: light sensor multiplexer
 
Hi Nitin, (...) Yes, sadly but true. That's why I have to use a battery anyway. (Or an output, but I would save it for other tasks.) (...) I understand. I should have explained what i'm doing with the sharps, sorry. I have a task running, that (...) (24 years ago, 21-Mar-01, to lugnet.robotics.rcx)

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