Forest Fighters Pi Wars 2021

Three video's in the bag and two to go. With the final submission date just around the corner we have been practising our driving skills for the challenges we still have to video. Here is a clip of our Feed the Fish setup. The ball contraption works well and the code has been modified to use the triggers on the controller to launch Audrey forward at top speed while simultaneously opening the contraption to send the ball forward when she stops sharply. Keen eyed observers might spot the similarity to the golf ball device used by Tractor Bot in the Golf challenge from 2017 and 2018. It was so good that we thought of it for the Feed the Fish challenge as soon as golf balls were mentioned. Credit to Keith's Pi Tutorials (@PiTutorials) of Ipswich Makerspace for the original STL. 

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.

The garden path code is now feature complete! It still needs a smidgen more tuning to be at 100% but here is our first full speed test run..... The third junction is missed, meaning this wouldn't count in competition, but we are quite pleased with the result.

We are still trying to improve the line following and are ensuring that the junctions are correctly navigated. If the line is straightforward, then we can follow at a decent frame rate (+32fps) but, as in the last post, we had real issues when we hit a junction. Looking at the Garden Path challenge rules, the highest amount of points can be obtained through using audio commands with camera based navigation (https://piwars.org/2021-vpw/challenges/up-the-garden-path/). While signposts did work, using the camera to follow the line and help with audio commands would seem to be the most reliable and best option. Below is a short video (once again using the rolling road on another screen for the Pi's camera to decode) but now with a USB microphone plugged into the Pi to issue commands to vosk (https://alphacephei.com/vosk/) with a limited list of words. Volume warning: It's a bit loud when Amy's Dad shouts the voice commands!!!! We need to see if we can't improve the latency ...

 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 keepi...

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...