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Subject: 
Re: Max-picking LIDAR
Newsgroups: 
lugnet.robotics
Date: 
Thu, 4 Mar 2004 14:55:12 GMT
Viewed: 
1040 times
  
John Barnes wrote:

I have a question which may help others duplicate your
work - did you expressly ensure the RCX IR "range" setting
was set to "long"?

   Yes. Here's a more complete test program, that comes close to duplicating my
original performance. Just download, & attach a forward-facing light sensor to
IN_2:

#define eye SENSOR_2

int reflect;

task main()
{
  SetSensor(eye, SENSOR_LIGHT);
  start lidar;
  SetUserDisplay(reflect,0);

   while(true)
   {
      switch(reflect/10)
      {
         case 1:
           PlayTone(440,1);
           break;
         case 2:
           PlayTone(880,1);
           break;
         case 3:
           PlayTone(1760,1);
           break;
      }
      Wait(1);
   }
}

task lidar()
{
  int x1,x2,x3,x4,ambient;
  SetTxPower(TX_POWER_HI);
  while(true)
  {
     ambient = eye;
     SendMessage(255);
     Wait(2);
     x1 = eye;
     x2 = eye;
     x3 = eye;
     x4 = eye;
     if (x2>x1) x1=x2;
     if (x3>x1) x1=x3;
     if (x4>x1) x1=x4;
     reflect = x1 - ambient;
  }
}

As a matter of interest, what effect does continuous message
transmission have on battery life?

   I've yet to test that... for that matter, I ought to use Recorder to measure
the difference in sensitivity to IR for RCX 1.0, 1.5, and 2.0 versions. Recorder
is fun to play with: you can watch a LEGO lightbulb "turn on" as the brightness
ramps up & down.

Also, did you know you can format up your own messages under
RCX2 firmware?

   No, I did not! How do you do that? Not only might that reduce power
consumption & decrease cycle time, but...

...a couple of FFs (or 00s - whichever causes continuous
transmission of bits)...

...would make it much easier to ensure a maximum reading! Where can I find
documentation on this? For that matter, does anyone know where I could get the
most up-to-date NQC guide? Since the web page moved, the guides seem to have
vanished (& I've only got the 2.3 guide).

As an observation, two Sumo bots doing this kind of detection
would cause some interesting results wouldn't they :)

   I got lucky - nobody else tried it, *this* time. But that's another reason I
came up with this routine. By taking a clean "ambient" reading, I can at least
detect IR interference (if the "ambient" reading is greater than the maximum
reflection reading, somebody else is emitting IR and making artificially bright
"ambient" readings). So while I can't yet completely counter jamming
(intentional or otherwise), I can deduce that it's occuring with this method.

--
Brian Davis



Message has 1 Reply:
  Re: Max-picking LIDAR
 
In lugnet.robotics, Brian Davis wrote: <SNIP> (...) <SNIP> Brian, thanks for posting this...I can't wait to try it out :) As for formatting your own messages in RCX 2.0 you can look at our (LRGoAA) communication protocol functions put together by (...) (21 years ago, 4-Mar-04, to lugnet.robotics)

Message is in Reply To:
  Re: Max-picking LIDAR
 
(...) .. major snippage ... Nice work! Although I like building custom sensors, I also really enjoy the ingenuity of people working with what's available. I have a question which may help others duplicate your work - did you expressly ensure the RCX (...) (21 years ago, 4-Mar-04, to lugnet.robotics)

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