False Positives and Line Following

 I've finally got around to laying out the Garden Path challenge and tested it with an unmodified line follower code used (supposed to be used) in Lava Plava. Needless to say, it kinda crashed and burned. It's not quite as bad as I expected but which fork the robot took was more by luck than any programming on our part.

I set up a Pi4 and camera pointing at my monitor with a "rolling road" displaying the computers view to determine how best to handle the junctions the robot will come across. The frame rate is nowhere near what we achieve on the robot, as the image is being streamed across SSH. However, for the purposes of recognising the junction patterns, it should be ok. The red border shows the detected line and the blue line shows the heading the robot needs to turn to to get the line back in the centre of view. The red figures indicate motor overall power (g) and, left(l) and right(r) motor power between 0 and 1. Turning right reduces the motor on the right keeping the left motor at 100%. The amount of reduction depends on the distance of the blue line from the centre.

For a straight line, we can snapshot it pretty reasonably.



Although when approaching a junction,


The robot takes an image of the whole junction. 


This will not trouble the robot as the general advance is forward. However, if we were supposed to turn left, then it would be an issue.  



Now the robot will have a problem as the weighting is to go left and then the short stub will get the robot's attention.

The next step is to either stop and wait for an audio command, signpost each junction or attempt to decode each junction by giving each an id.

To be continued...






Comments

Post a Comment

Popular posts from this blog

Add a timer to your video submissions

Image
Part of the recommendations for the video submissions for each challenge, is to arrange for the video to have a timer overlay, like you might see when a sporting event is shown on TV.  We have been using kdenlive ( https://kdenlive.org/en/ ) for editing videos and can recommend it. There are builds for Windows, Linux and Mac and it just so happens that kdenlive can add a timer overlay to a video clip. (Its also free and open source). Amy's dad has produced a short video showing how to add a timer to your challenge videos, using the kdenlive Dynamic Text effect.  kdenlive can also be used to add lead-in, and titles to make the judges life easier. ..and not for the faint-hearted here is the resultant video, including lead in, titles and timer overlay. We will be using this timer technique on all our Pi Wars 2021 videos.
Read more

Happy New Year (and we hope its better than the last)

Image
Gripper update. The grippers have been sprayed and a non-slip coating has been added. Grippers The software has been modded slightly to maintain continuous pressure on the block, once the grippers close, and a control button to switch off the gripper servo when the grippers are not closed. This seems to work reasonably well but we might require more tweaking as the cubes are quite slippery. Blocks We now have three cubes of different colours for the "Tidy Up The Toys" challenge. Amy has produced some nice menu artwork including this one for "Feed the Fish". Carping On She will also be giving a talk at the PiWars conference about this and her other digital art, see https://piwars.org/2021-vc/ for details.  Feed the Fish Team Forest Fighters still can't decide how to do this challenge either using a catapult or shove halfpenny methods. Having printed a catapult and launching nerf rounds across the lounge never to be seen again behind the TV, we are thinking thi
Read more

Into the unknown with Voice Commands.

Image
Amy's dad here with a quick update on PiWars 2021 progress..... We have busy with other projects so its been pretty quiet on the Pi Wars front, however the basic robot software and hardware is essentially going to be the same as last year (2020) but with added voice commands.  I have been checking out Vosk as a way of getting a Pi to understand voice commands. Here is a quick video showing its not too shabby, especially for single word commands. The main advantage of Vosk is that it is local to the machine rather than using the "Cloud" so even if your cloud service provider is down (note Google authentication went down yesterday for a couple of  hours so not impossible!) you can still command your system using voice. Also it doesn't seem to use much processor (considering I recorded the video over VNC!)
Read more