Chief Delphi - Raspberry Pi as Coprocessor

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Raspberry Pi as Coprocessor

We plan on using the Raspberry Pi to do our vision processing. How would we output Python script results (after processing) and receive on RoboRio (Java)? I looked into pynetworktables and am confused on how to receive the data from the RoboRio.

Re: Raspberry Pi as Coprocessor

GRIP has some examples. Specifically samples/frc_find_red_areas.

Basically, you just publish your results to NetworkTables with the pi connected to the roborio/radio/switch with an ethernet cable, then you can read that from your robot program.

Re: Raspberry Pi as Coprocessor

Quote:

Originally Posted by SamCarlberg (Post 1632676)

Hi, I am working on the same thing, but in Java. Is there documentation for Network tables in java?

Re: Raspberry Pi as Coprocessor

Quote:

Originally Posted by SamCarlberg (Post 1635528)

Javadocs here

Thanks, could you take a look at this code I found on another thread:

Code:

//========================================

//Robot Code

// declare object

NetworkTable cameraTable;



// getinstance (table is a singleton, if one does not exist then one will

// be created otherwise returns reference to existing instance

cameraTable = NetworkTable.getTable("camera");



// get data element from the table

// default values returned if no data has been provided from another source yet



cameraTable.beginTransaction();

Boolean imageFound = cameraTable.getBoolean("found", false );

Double imageOffset = cameraTable.getDouble("offset", -1.0);

Double imageDistance = cameraTable.getDouble("distance", -1.0);

cameraTable.endTransaction();



System.out.println( "found = " + imageFound);

System.out.println( "offset = " + imageOffset);

System.out.println( "distance = " + imageDistance);



//=======================================

// Driver Station PC

// camera image processing is done in C# application on DS



// declare it

private NetworkTable table;



// Init NetworkTable

NetworkTable.setIPAddress("10.6.23.2");  // ip of crio

table = NetworkTable.getTable("camera");





// in the image processing loop



table.beginTransaction();

table.putBoolean("found", true);

table.putDouble("distance", distance);

table.putDouble("offset", offset);

table.endTransaction();

[/quote]

Looks like what I need, but is it missing something (ie setTeam, etc.)?

Re: Raspberry Pi as Coprocessor

That example is 4 years old. All you have to do on the pi:

Code:

NetworkTable.setClientMode();

NetworkTable.setTeamNumber(1512);

ITable visionTable = NetworkTable.getTable("vision");

That'll set up the pi and a table specifically for vision. If you launch OutlineViewer from Eclipse (WPILib > Launch OutlineViewer), you'll be able to see the values update in realtime.

Then to publish the results from the vision processing

Code:

visionTable.putBoolean("Have target", haveTarget);

visionTable.putNumber("Angle to target", angleToTarget);

...

In your robot program, you'd also declare a table for vision just like we did on the pi. To read the values the pi is publishing, use the corresponding 'get' methods

Code:

haveTarget = visionTable.getBoolean("Have target", false); // default to false

targetAngle = visionTable.getNumber("Angle to target", 0); // default to 0

...

Re: Raspberry Pi as Coprocessor

Quote:

Originally Posted by SamCarlberg (Post 1635537)

That example is 4 years old. All you have to do on the pi:

Code:

NetworkTable.setClientMode();

NetworkTable.setTeamNumber(1512);

ITable visionTable = NetworkTable.getTable("vision");

Code:

visionTable.putBoolean("Have target", haveTarget);

visionTable.putNumber("Angle to target", angleToTarget);

...

In your robot program, you'd also declare a table for vision just like we did on the pi. To read the values the pi is publishing, use the corresponding 'get' methods

Code:

haveTarget = visionTable.getBoolean("Have target", false); // default to false

targetAngle = visionTable.getNumber("Angle to target", 0); // default to 0

...

Does anyone know of a vision processing tutorial?

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