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Have you tried using the computer monitor? ie: display the bar code on your
computer screen and scan along the code? this may make a simple scout/code
pilot programmer possible.
-Rich
In lugnet.robotics, Doug Eaton writes:
> Summary: * The Micro Scout can be program by flashing a light at it.
> * Use transparencies as a low tech means of doing this.
>
> A more detailed version is available at http://eaton.dhs.org/lego/
>
> The Droid Developers Kit is the first and only MindStorms set that many of
> us have either because is was cheap or because it offers R2D2. After
> playing with the toy programs built into the brick, the mysterious P mode
> cries out yearning to be discovered. The manual tells us to check the web
> site for more information but the web side declines to comment stating:
> check back in Fall 2000.
>
> Fortunately the Scout SDK has an appendix that shows the codes understood by
> the Micro Scout and ties these in to bar codes understood by the Code
> Pilot. Analyzing the bar codes was the first step.
>
> Step 1: Understanding VLL
>
> VLL is a binary bar code comprised of: Start bit, Checksum, Data, Stop bit.
> A simple example shows encoding VLL message 0 (Motor Forward for both the
> Code Pilot and the Micro Scout):
>
> #_##_##_##__#__#__#__#__#__#__#_### #: Darkness (usually a bar)
> S <-cksm-> <-------data-------> Stop _: Bright light (white paper)
>
> A VLL code is 35 time intervals in length. The start bit is 1 unit wide,
> the stop bit is 3 units plus the space before it. The checksum and data are
> binary digits with 0 being two spaces and a bar while 1 is a space and a
> double width bar. The checksum is 3 digits and the data is 7 digits. The
> data is the VLL code from 0 to 127. The checksum for VLL code n is:
> 7-(n+n/4+n/16). This was derived from analysis of about 30 bar codes for
> the Code Pilot.
>
> Step 2: Talking VLL to the Micro Scout
>
> If you have a Scout, the easiest way is to get the SDK and have the Scout
> talk to its little brother. Skip on to the next section to take the easy
> way out.
>
> The first step is to determine light and dark. This easiest done by running
> the built in Seek Light program (3.) I could not get white paper to
> register as light so I photocopied the bar codes onto overhead
> transparencies. Ok, I could get a code to register if I held the piece of
> paper 4 inches away from a 60 watt light bulb and then, it would only
> register once of every dozen scan attempts. I had the best results when
> placing the MicroScout on a table directly under a bright light bulb (point
> source) and passing the transparency directly over the sensor.
>
> Note that the Micro Scout uses the light level when it is first powered on
> to indicate darkness. Ensure the sensor is getting a view of what you are
> trying to call black when powering on the Micro Scout to ensure proper
> calibration of the bar codes you wish to scan.
>
> The Code Pilot has a standard bar width of 1/32 of an inch. My Micro Scout
> could not decode these. I expanded them up to 1/8 inch. This allows 3 large
> codes per transparency. Future experimentation may prove a smaller bar code
> will suffice. I chose to print the codes 2.5 inches high to ensure the
> sensor is registering the bars and not the white above or below the code.
> For now, grab a copy of my Postscript program which prints all 29
> documented codes the Micro Scout on 10 pages and try it out for yourself.
>
> My Micro Scout bar codes are available at http://eaton.dhs.org/lego/
>
> The next step for me will be to bring an old computer out of retirement and
> let it control an LED directly (emulating the scout) so I do not have to
> keep all the transparencies around. One thing I assume will be required is
> a period of light before the start bit. This will remain theory until I
> have time to experiment further or someone else beats me to it.
>
> Step 3: Writing a Program
>
> First turn the Micro Scout on and place it in P mode. Remember that it
> calibrates its light sensor for darkness when first turned on.
>
> Flash one of the 17 scripting codes at it. You just started a new program.
> Any previous program was erased. Flash some more scripting codes to create
> a longer program.
>
> Step 4: Execute the Program
>
> The Run button executes the current program. The script is completed. If
> you want to add to a script once it has executed, you have to reenter it
> from the beginning. This is not too bad since the longest program you may
> enter is only 15 instructions. The VLL code Run performs the same function
> as the Run button.
>
> VLL is disabled while a program or script is running. Reset and Motor Stop
> are ignored as far as I can tell. The only way I could interrupt a program
> is with the buttons and not my bar codes.
>
> Happy Hacking!
> Doug
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Message has 1 Reply:
 | | Re: Micro Scout programming with VLL bar code: HOWTO
|
| Richard Earley writes: > > Have you tried using the computer monitor? ie: display the bar code on your > computer screen and scan along the code? this may make a simple scout/code > pilot programmer possible. Even better, flash a big square in the (...) (25 years ago, 11-Jan-00, to lugnet.robotics)
|
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