Obtaining Lego Encoder Readings

Question

I'm trying to get a Lego NXT motor to rotate a specific certain number of degrees, and I think the best way to do that is to use an encoder.  I'm having some trouble doing that though.  I'm setting up the encoder in my manifest file just like I set up the motors, and they work perfectly.  Then I set up the encoder port and subsribe to it.  Then when I run the service I get this error:

 

*** Manifest Loader: Creating service failed: http://schemas.microsoft.com/robot
ics/2006/05/encoder.html.
Reason: Could not load type 'Microsoft.Robotics.Services.Encoder.' from assembly
 'RoboticsCommon, Version=1.0.446.3, Culture=neutral, PublicKeyToken=31bf3856ad3
64e35'. [07/16/2007 13:15:18][http://natasha:50000/manifestloader/5301d1a8-dd8c-
4fa1-96a5-bff0afaa8237]

 

 

 

I've tried uninstalling and reinstalling MSRS, but I still get the same error when I go to run the service.  Am I doing something wrong?  What causes this error? 

Answer 1

I did some more poking around, and I've determined that the problem is in this part of my manifest file:

Code Snippet

<!--Start Lego Encoder-->

<ServiceRecordType>

<dssp:Contract>http://schemas.microsoft.com/robotics/2006/05/encoder.html</dssp:Contract>

<dssp:PartnerList>

<dssp:Partner>

<dssp:Service>GrabEncoder.Config.xml</dssp:Service>

<dssp:Name>dssp:StateService</dssp:Name>

</dssp:Partner>

<dssp:Partner>

<dssp:Name>lego:Brick1</dssp:Name>

</dssp:Partner>

</dssp:PartnerList>

<Name>encoder:GrabEncoder</Name>

</ServiceRecordType>

 

If I comment that part out, it does not give me the error.  It doesn't work, obviously, because it no longer knows that an encoder is supposed to be there, but the error is definitely being caused by this code.  Any suggestions?

Answer 2

for some reason the the DLLs seem to be mismatched. Did you install on top of an older install? Did you do a partial recompile?

Answer 3

I did have MSRS 1.0 installed on this computer, but I uninstalled that at least a month ago.  I've been using they May release of 1.5 since then, including to create this service.  I did uninstall 1.5, delete the directory, and reinstall the same version in the hopes that that would solve some problems.  I used the same copy of this service before and after the reinstallation.  I always use F5 to compile and run my projects, so I don't think that I would do a partial compile.

 

I just tried again to uninstall and reinstall, but it's giving me the same error.  I've tried to clean and rebuild the solution, made sure that the proxies are in the correct directories, and tried changing around my code.  I'm stumped!

 

This is my entire manifest file:

Code Snippet

<?xml version="1.0" ?>

<Manifest

xmlns="http://schemas.microsoft.com/xw/2004/10/manifest.html"

xmlns:dssp="http://schemas.microsoft.com/xw/2004/10/dssp.html"

xmlns:motor="http://schemas.microsoft.com/robotics/2006/05/motor.html"

xmlns:lego="http://schemas.microsoft.com/robotics/2006/05/legonxt.html"

xmlns:legoencoder="http://schemas.microsoft.com/2006/06/legonxtencoder.html"

xmlns:encoder="http://schemas.microsoft.com/robotics/2006/05/encoder.html"

>

<CreateServiceList>

<ServiceRecordType>

<dssp:Contract>http://schemas.tempuri.org/2007/07/stalkerbot.html</dssp:Contract>

<dssp:PartnerList>

<dssp:Partner>

<dssp:Name>motor:LeftMotor</dssp:Name>

</dssp:Partner>

<dssp:Partner>

<dssp:Name>motor:RightMotor</dssp:Name>

</dssp:Partner>

<dssp:Partner>

<dssp:Name>motor:GrabMotor</dssp:Name>

</dssp:Partner>

<dssp:Partner>

<dssp:Name>encoder:GrabEncoder</dssp:Name>

</dssp:Partner>

</dssp:PartnerList>

 

 

</ServiceRecordType>

 

<!--Start LegoNXT Brick -->

<ServiceRecordType>

<dssp:Contract>http://schemas.microsoft.com/robotics/2006/05/legonxt.html</dssp:Contract>

<dssp:PartnerList>

<!--Initial LegoNXT config file -->

<dssp:Partner>

<dssp:Service>LEGO.NXT.Brick.Config.xml</dssp:Service>

<dssp:Name>dssp:StateService</dssp:Name>

</dssp:Partner>

</dssp:PartnerList>

<Name>lego:Brick1</Name>

</ServiceRecordType>

 

<!-- Start Lego LeftMotor -->

<ServiceRecordType>

<dssp:Contract>http://schemas.microsoft.com/2006/06/legonxtmotor.html</dssp:Contract>

<dssp:PartnerList>

<dssp:Partner>

<dssp:Service>LeftMotor.Config.xml</dssp:Service>

<dssp:Name>dssp:StateService</dssp:Name>

</dssp:Partner>

<dssp:Partner>

<dssp:Name>lego:Brick1</dssp:Name>

</dssp:Partner>

</dssp:PartnerList>

<Name>motor:LeftMotor</Name>

</ServiceRecordType>

 

 

<!-- Start Lego RightMotor-->

<ServiceRecordType>

<dssp:Contract>http://schemas.microsoft.com/2006/06/legonxtmotor.html</dssp:Contract>

<dssp:PartnerList>

<dssp:Partner>

<dssp:Service>RightMotor.Config.xml</dssp:Service>

<dssp:Name>dssp:StateService</dssp:Name>

</dssp:Partner>

<dssp:Partner>

<dssp:Name>lego:Brick1</dssp:Name>

</dssp:Partner>

</dssp:PartnerList>

<Name>motor:RightMotor</Name>

</ServiceRecordType>

<!-- Start Lego GrabMotor-->

<ServiceRecordType>

<dssp:Contract>http://schemas.microsoft.com/2006/06/legonxtmotor.html</dssp:Contract>

<dssp:PartnerList>

<dssp:Partner>

<dssp:Service>GrabMotor.Config.xml</dssp:Service>

<dssp:Name>dssp:StateService</dssp:Name>

</dssp:Partner>

<dssp:Partner>

<dssp:Name>lego:Brick1</dssp:Name>

</dssp:Partner>

</dssp:PartnerList>

<Name>motor:GrabMotor</Name>

</ServiceRecordType>

 

<!--Start Lego GrabEncoder

<ServiceRecordType>

<dssp:Contract>http://schemas.microsoft.com/robotics/2006/05/encoder.html</dssp:Contract>

<dssp:PartnerList>

<dssp:Partner>

<dssp:Service>GrabEncoder.Config.xml</dssp:Service>

<dssp:Name>dssp:StateService</dssp:Name>

</dssp:Partner>

<dssp:Partner>

<dssp:Name>lego:Brick1</dssp:Name>

</dssp:Partner>

</dssp:PartnerList>

<Name>encoder:GrabEncoder</Name>

</ServiceRecordType>-->

 

</CreateServiceList>

</Manifest>

 

If I leave the encoder bit commented out as above, the code works fine.  However, when I go to check the encoder values through the web interface, the hardware identifier is -1.  I have the hardware identifier set to 3 in the file GabEncoder.Config.xml, but with that commented out, MSRS has no idea where it is.  So I'm assuming I need the commented out part to have the hardware work correctly, but my code doesn't seem to like that part.  Eek!

Answer 4

You may have already tried this, but it sounds like you brought your application forward. 

 

Did you run DssProjectMigration?

If you haven't done this, open an MSRS 1.5 Command Prompt, change to your project directory, then run the following:

Code Snippet

 

> DssProjectMigration .

 

(there is a parameter with a single period '.' at the end) 

 

After this, open your project and check for version specific references. 

References to MSRS assemblies should always be "Copy Local": false and "Specific Version": false.

 

If Specific Version is true, it will retain a reference to the earlier DLL, even though you ran the Project Migration tool.

 

David

Answer 5

I just checked, and the copy local and specific version were both set to true on RoboticsCommon.proxy.  So I followed your directions, but it still does the same thing.  Maybe if I start a new project and make sure that they are both set to false before I run it for the first time?  It's worth a shot, I'm running out of ideas!  I'll try that tomorrow.

Answer 6

Grr.  I tried starting a new project and making sure that the copy local and specific version fields were both false before I ran it, still the same error.  Does anybody have the lego encoders working in code?  What am I doing wrong?

Answer 7

Unfortunately, once you compiled with the Copy Local settings to true, it is likely that the RoboticCommon.dll (or whichever dll's were referenced) copied the older version in to the bin directory of your MSRS 1.5 installation.   You can check by viewing the dll properties in Windows Explorer (in the details tab).

In this case, a reinstall is necessary. 

 

btw, After I do a clean install, I save a backup of the entire installed directories.  Since we don't muck with the registry, you can just copy the original files back in order to fix this type of problem, this is also handy if I'm playing around with the samples, but I want to snap them back to what was shipped... and much quicker than a reinstall.

 

 

 

 

Answer 8

Hello Kexyn.  Just wondering if your issue is resolved.  Did you get NXT encoders working?

 

BTW, we are doing some major work on LEGO NXT for a future release to make is easier to configure and use from VPL and to incorporate the ability to work with third party sensors.  Stay tuned.

Answer 9

Hello again.  Unfortunately, I still haven't got my NXT encoders to work.  Which is strange, because I had a similar problem with the NXT sonar sensors.  I'm getting the same error:

 

Code Snippet

*** Manifest Loader: Creating service failed: http://schemas.microsoft.com/robot
ics/2006/05/encoder.html.
Reason'>http://schemas.microsoft.com/robot">http://schemas.microsoft.com/robot
ics/2006/05/encoder.html.
Reason: System.TypeLoadException: Could not load type 'Microsoft.Robotics.Servic
es.Encoder.' from assembly 'RoboticsCommon, Version=1.5.507.0, Culture=neutral,
PublicKeyToken=31bf3856ad364e35'.

 

 

But I got my sonar working fine.  I've made sure everything is as it should be with my encoders, everything is pretty much identical except for the word encoder instead of sonar.  For some reason though, it still throws that error every time I run the service.  I can get everything else working fine, the encoder is the last lego piece that's giving me trouble.

Answer 10

In 1.5, I built a manifest and added an encoder service.  It all works fine for me. 

My manifest looks a little different... have you tried using our new manifest editor to make sure your manifest is constructed ok?

 

Code Snippet

vpl -m YourLegoNxtTest.Manifest.xml

 

 

 

 

Answer 11

I redid my manifest file, and now it works perfectly.  Thanks a lot!  The manifest editor is an interesting addition..

Answer 12

Hi, I've been trying to get my NXT encoder to work. My encoder seems to start up successfully, but when I check the encoder service instance page in "Service Directory", the readings would never change no matter how I refresh the page. I'm thinking that something may have been wrong with my manifest.

I'm using the DSS Manifest Editor to generate the manifest, as follows.
Any comments would be appreciated.
Thank you.

Code Block

<?xml version="1.0"?>
<Manifest xmlns:legonxtsonar="http://schemas.microsoft.com/2006/06/legonxtsonar.html" xmlns:charlie="http://schemas.tempuri.org/2007/09/charlie.html" xmlns:dssp="http://schemas.microsoft.com/xw/2004/10/dssp.html" xmlns:this="urn:uuid:111fa31b-05dc-4dbd-9978-2098c144687c" xmlns:legonxt="http://schemas.microsoft.com/robotics/2006/05/legonxt.html" xmlns:legonxtmotor="http://schemas.microsoft.com/2006/06/legonxtmotor.html" xmlns:legonxtencoder="http://schemas.microsoft.com/2006/06/legonxtencoder.html" xmlns:legonxtlightsensor="http://schemas.microsoft.com/2006/06/legonxtlightsensor.html" xmlns:legonxtsound="http://schemas.microsoft.com/2006/06/legonxtsound.html" xmlns:motor="http://schemas.microsoft.com/robotics/2006/05/motor.html" xmlns:bumper="http://schemas.microsoft.com/2006/06/lego.nxt.bumper.html" xmlns="http://schemas.microsoft.com/xw/2004/10/manifest.html">
  <CreateServiceList>
    <ServiceRecordType>
      <dssp:Contract>http://schemas.tempuri.org/2007/09/charlie.html</dssp:Contract>
      <dssp:PartnerList>
        <dssp:Partner>
          <dssp:Contract>http://schemas.microsoft.com/2006/06/legonxtmotor.html</dssp:Contract>
          <dssp:PartnerList />
          <dssp:Name>motor:MotorA</dssp:Name>
          <dssp:ServiceName>this:MotorA</dssp:ServiceName>
        </dssp:Partner>
        <dssp:Partner>
          <dssp:Contract>http://schemas.microsoft.com/2006/06/legonxtmotor.html</dssp:Contract>
          <dssp:PartnerList />
          <dssp:Name>motor:MotorB</dssp:Name>
          <dssp:ServiceName>this:MotorB</dssp:ServiceName>
        </dssp:Partner>
        <dssp:Partner>
          <dssp:Contract>http://schemas.microsoft.com/2006/06/legonxtmotor.html</dssp:Contract>
          <dssp:PartnerList />
          <dssp:Name>motor:MotorC</dssp:Name>
          <dssp:ServiceName>this:MotorC</dssp:ServiceName>
        </dssp:Partner>
        <dssp:Partner>
          <dssp:Contract>http://schemas.microsoft.com/2006/06/contactsensor.html</dssp:Contract>
          <dssp:PartnerList />
          <dssp:Name>charlie:bumper</dssp:Name>
          <dssp:ServiceName>this:BumperA</dssp:ServiceName>
        </dssp:Partner>
        <dssp:Partner>
          <dssp:Contract>http://schemas.microsoft.com/robotics/2006/06/sonar.html</dssp:Contract>
          <dssp:PartnerList />
          <dssp:Name>charlie:sonar</dssp:Name>
          <dssp:ServiceName>this:SonarA</dssp:ServiceName>
        </dssp:Partner>
        <dssp:Partner>
          <dssp:Contract>http://schemas.microsoft.com/robotics/2006/06/analogsensor.html</dssp:Contract>
          <dssp:PartnerList />
          <dssp:Name>charlie:analog</dssp:Name>
          <dssp:ServiceName>this:AnalogA</dssp:ServiceName>
        </dssp:Partner>
        <dssp:Partner>
          <dssp:Contract>http://schemas.microsoft.com/2006/06/legonxtsound.html</dssp:Contract>
          <dssp:PartnerList />
          <dssp:Name>charlie:sound</dssp:Name>
          <dssp:ServiceName>this:SoundA</dssp:ServiceName>
        </dssp:Partner>
        <dssp:Partner>
          <dssp:Contract>http://schemas.microsoft.com/robotics/2006/05/encoder.html</dssp:Contract>
          <dssp:PartnerList />
          <dssp:Name>charlie:encoder</dssp:Name>
          <dssp:ServiceName>this:EncoderA</dssp:ServiceName>
        </dssp:Partner>
      </dssp:PartnerList>
      <Name>this:charlie</Name>
    </ServiceRecordType>
    <ServiceRecordType>
      <dssp:Contract>http://schemas.microsoft.com/robotics/2006/05/legonxt.html</dssp:Contract>
      <dssp:PartnerList>
        <dssp:Partner>
          <dssp:Contract>http://schemas.microsoft.com/robotics/2006/05/legonxt.html</dssp:Contract>
          <dssp:Service>lego.nxt.brick.config.xml</dssp:Service>
          <dssp:PartnerList />
          <dssp:Name>dssp:StateService</dssp:Name>
        </dssp:Partner>
      </dssp:PartnerList>
      <Name>this:Brick1</Name>
    </ServiceRecordType>
    <ServiceRecordType>
      <dssp:Contract>http://schemas.microsoft.com/2006/06/legonxtmotor.html</dssp:Contract>
      <dssp:PartnerList>
        <dssp:Partner>
          <dssp:Contract>http://schemas.microsoft.com/2006/06/legonxtmotor.html</dssp:Contract>
          <dssp:Service>lego.nxt.motora.config.xml</dssp:Service>
          <dssp:PartnerList />
          <dssp:Name>dssp:StateService</dssp:Name>
        </dssp:Partner>
        <dssp:Partner>
          <dssp:Contract>http://schemas.microsoft.com/robotics/2006/05/legonxt.html</dssp:Contract>
          <dssp:PartnerList />
          <dssp:Name>legonxtmotor:LegoNxt</dssp:Name>
          <dssp:ServiceName>this:Brick1</dssp:ServiceName>
        </dssp:Partner>
      </dssp:PartnerList>
      <Name>this:MotorA</Name>
    </ServiceRecordType>
    <ServiceRecordType>
      <dssp:Contract>http://schemas.microsoft.com/2006/06/legonxtmotor.html</dssp:Contract>
      <dssp:PartnerList>
        <dssp:Partner>
          <dssp:Contract>http://schemas.microsoft.com/2006/06/legonxtmotor.html</dssp:Contract>
          <dssp:Service>lego.nxt.motorb.config.xml</dssp:Service>
          <dssp:PartnerList />
          <dssp:Name>dssp:StateService</dssp:Name>
        </dssp:Partner>
        <dssp:Partner>
          <dssp:Contract>http://schemas.microsoft.com/robotics/2006/05/legonxt.html</dssp:Contract>
          <dssp:PartnerList />
          <dssp:Name>legonxtmotor:LegoNxt</dssp:Name>
          <dssp:ServiceName>this:Brick1</dssp:ServiceName>
        </dssp:Partner>
      </dssp:PartnerList>
      <Name>this:MotorB</Name>
    </ServiceRecordType>
    <ServiceRecordType>
      <dssp:Contract>http://schemas.microsoft.com/2006/06/legonxtmotor.html</dssp:Contract>
      <dssp:PartnerList>
        <dssp:Partner>
          <dssp:Contract>http://schemas.microsoft.com/2006/06/legonxtmotor.html</dssp:Contract>
          <dssp:Service>lego.nxt.motorc.config.xml</dssp:Service>
          <dssp:PartnerList />
          <dssp:Name>dssp:StateService</dssp:Name>
        </dssp:Partner>
        <dssp:Partner>
          <dssp:Contract>http://schemas.microsoft.com/robotics/2006/05/legonxt.html</dssp:Contract>
          <dssp:PartnerList />
          <dssp:Name>legonxtmotor:LegoNxt</dssp:Name>
          <dssp:ServiceName>this:Brick1</dssp:ServiceName>
        </dssp:Partner>
      </dssp:PartnerList>
      <Name>this:MotorC</Name>
    </ServiceRecordType>
    <ServiceRecordType>
      <dssp:Contract>http://schemas.microsoft.com/2006/06/lego.nxt.bumper.html</dssp:Contract>
      <dssp:PartnerList>
        <dssp:Partner>
          <dssp:Contract>http://schemas.microsoft.com/2006/06/lego.nxt.bumper.html</dssp:Contract>
          <dssp:Service>lego.nxt.bumpera.config.xml</dssp:Service>
          <dssp:PartnerList />
          <dssp:Name>dssp:StateService</dssp:Name>
        </dssp:Partner>
        <dssp:Partner>
          <dssp:Contract>http://schemas.microsoft.com/robotics/2006/05/legonxt.html</dssp:Contract>
          <dssp:PartnerList />
          <dssp:Name>bumper:LegoNxt</dssp:Name>
          <dssp:ServiceName>this:Brick1</dssp:ServiceName>
        </dssp:Partner>
      </dssp:PartnerList>
      <Name>this:BumperA</Name>
    </ServiceRecordType>
    <ServiceRecordType>
      <dssp:Contract>http://schemas.microsoft.com/2006/06/legonxtsonar.html</dssp:Contract>
      <dssp:PartnerList>
        <dssp:Partner>
          <dssp:Contract>http://schemas.microsoft.com/2006/06/legonxtsonar.html</dssp:Contract>
          <dssp:Service>lego.nxt.sonara.config.xml</dssp:Service>
          <dssp:PartnerList />
          <dssp:Name>dssp:StateService</dssp:Name>
        </dssp:Partner>
        <dssp:Partner>
          <dssp:Contract>http://schemas.microsoft.com/robotics/2006/05/legonxt.html</dssp:Contract>
          <dssp:PartnerList />
          <dssp:Name>legonxtsonar:LegoNxt</dssp:Name>
          <dssp:ServiceName>this:Brick1</dssp:ServiceName>
        </dssp:Partner>
      </dssp:PartnerList>
      <Name>this:SonarA</Name>
    </ServiceRecordType>
    <ServiceRecordType>
      <dssp:Contract>http://schemas.microsoft.com/2006/06/legonxtlightsensor.html</dssp:Contract>
      <dssp:PartnerList>
        <dssp:Partner>
          <dssp:Contract>http://schemas.microsoft.com/2006/06/legonxtlightsensor.html</dssp:Contract>
          <dssp:Service>lego.nxt.analoga.config.xml</dssp:Service>
          <dssp:PartnerList />
          <dssp:Name>dssp:StateService</dssp:Name>
        </dssp:Partner>
        <dssp:Partner>
          <dssp:Contract>http://schemas.microsoft.com/robotics/2006/05/legonxt.html</dssp:Contract>
          <dssp:PartnerList />
          <dssp:Name>legonxtlightsensor:LegoNxt</dssp:Name>
          <dssp:ServiceName>this:Brick1</dssp:ServiceName>
        </dssp:Partner>
      </dssp:PartnerList>
      <Name>this:AnalogA</Name>
    </ServiceRecordType>
    <ServiceRecordType>
      <dssp:Contract>http://schemas.microsoft.com/2006/06/legonxtsound.html</dssp:Contract>
      <dssp:PartnerList>
        <dssp:Partner>
          <dssp:Contract>http://schemas.microsoft.com/2006/06/legonxtsound.html</dssp:Contract>
          <dssp:Service>lego.nxt.sounda.config.xml</dssp:Service>
          <dssp:PartnerList />
          <dssp:Name>dssp:StateService</dssp:Name>
        </dssp:Partner>
        <dssp:Partner>
          <dssp:Contract>http://schemas.microsoft.com/robotics/2006/05/legonxt.html</dssp:Contract>
          <dssp:PartnerList />
          <dssp:Name>legonxtsound:LegoNxt</dssp:Name>
          <dssp:ServiceName>this:Brick1</dssp:ServiceName>
        </dssp:Partner>
      </dssp:PartnerList>
      <Name>this:SoundA</Name>
    </ServiceRecordType>
    <ServiceRecordType>
      <dssp:Contract>http://schemas.microsoft.com/2006/06/legonxtencoder.html</dssp:Contract>
      <dssp:PartnerList>
        <dssp:Partner>
          <dssp:Contract>http://schemas.microsoft.com/2006/06/legonxtencoder.html</dssp:Contract>
          <dssp:Service>lego.nxt.encodera.config.xml</dssp:Service>
          <dssp:PartnerList />
          <dssp:Name>dssp:StateService</dssp:Name>
        </dssp:Partner>
        <dssp:Partner>
          <dssp:Contract>http://schemas.microsoft.com/robotics/2006/05/legonxt.html</dssp:Contract>
          <dssp:PartnerList />
          <dssp:Name>legonxtencoder:LegoNxt</dssp:Name>
          <dssp:ServiceName>this:Brick1</dssp:ServiceName>
        </dssp:Partner>
      </dssp:PartnerList>
      <Name>this:EncoderA</Name>
    </ServiceRecordType>
  </CreateServiceList>
</Manifest>

Answer 13

Hello echoseven,

 

It is difficult to tell just from the manifest, but I don't see any obvious problems. 

 

The second place to look is the initial configuration file (lego.nxt.brick.config.xml).  Using the LEGO NXT configuration web page, make sure your motor configuration type is "Encoder", and the "External Range" is **not** checked.

 

One other note.  Very shortly, we will be releasing a new LEGO NXT package for MSRS 1.5.  This new package will make using the encoders very easy.  Furthermore, you will get encoder readings in degrees (360 per rotation).  This will allow much finer control of the motors.

 

Stay tuned for this package.

Dave

Answer 14

Hi.  This is available now.  The new Motor service has easily accessible encoders.

 

All New LEGO NXT services available for Microsoft Robotics Studio 1.5!

 

Check out the download here:

Samples Update for Microsoft Robotics Studio (1.5)

 

and documentation on MSDN:

http://msdn2.microsoft.com/en-us/library/bb870583.aspx