Days tick by......

 With less than a month to go it seems we have lots of solutions which are all but ready to go. Line followers that can see lines but can they drive seven metres in a straight line? Square finders that can see the squares, but can they drive to one and then the next? All will be revealed on the 21st April in Cambridge but for now here's some progress.

The Lava Palaver line detector works well but instead of a fixed mount, needed a bit of adjustment so has now been given an articulated mount.

This has been 3D printed to be integral with the magnet attached battery box cover. More magnets have been deployed to the rear part of the robot for quick change attachments for shooting zombies and collecting barrels.

It's great to see the layout before dozens of wires obscure the view!!!! More uses for magnets has been found in adjusting the barrel handler. 

This also makes it quicker and easier to change the types of attachment to see which works best. 

This is our barrel handler in serious searchlight mode. It obviously works but needs a bit more software behind it to get barrels to their destination. 

More on this to come. 

The Escape Route challenge still needs a bit of work, but we're working from an old formula so it's more tidying up than new development. To get cleaner lines on the robot we've hidden a VL53 laser range finder inside one of the cab windows, along with IR sensors on the sides and an ultrasonic sensor on the front of the robot.

When not in use we'll be closing the window with bluetack!!!!

First experiments with the sensors aren't perfect, as the following video shows.

But after a bit of tuning and building a test course, it's starting to look the part.

 

This is our goth themed video selection but we just need to get this running a bit more smoothly.

 We've had a solution for Minesweeper for sometime, but we've only just now got round to fitting it to the robot. 

It's an overhead gantry mounted camera which reports an XY co-ordinate of the red illuminated square on demand from the robot. The robot will be running on mecanum wheels for this challenge and the gantry is adjustable to keep the robot within the height limit of 450mm. Navigation is all relative to the red square, so, see a red square and drive to it!! To reduce the impact of the gantry on the image, 4mm black carbon fibre rods have been used for support. Also in the picture is the carry handle for the robot, to make handling easier and safer. A better view here.

With a variety of configurations needed for the competition day, a new control panel is being created for the rear of the robot which will allow the robots Pi to be quickly switched between challenge modes, as well as a battery monitor and a start/stop button. To make sure we've got everything covered for each challenge configuration, we've started a checklist, I'm sure it'll get longer soon!!! Here's where it is now.

Challenge: Lava Palaver

• Wheels: 105mm
• Bonnet: Line Detector
• Back cover: Plain
• Attachment name: LINES

Challenge: Zombie Apocalypse

• Wheels: 70mm
• Bonnet: Plain
• Back cover: Nerf Gun
• Attachment name: ZOMBI

Challenge: Eco-Disaster

• Wheels: 70mm
• Bonnet: ???Not yet determined???
• Back cover: Barrel Picker
• Attachment name: ECODI

Challenge: Minesweeper

• Wheels: Mecanum
• Bonnet: Plain
• Back cover: Camera Gantry
• Attachment name: MINES

Challenge: Escape Route

• Wheels: 70mm
• Bonnet: Ultrasonic detector
• Back cover: Plain
• Attachment name: None

Challenge: Pi Noon

• Wheels: Mecanum
• Bonnet: Balloon attachment
• Back cover: Plain
• Attachment name: RC

Challenge: Temple of Doom

• Wheels: 105mm
• Bonnet: Plain
• Back cover: Plain
• Attachment name: RC

Next time we hope to have more demonstration videos of being fully ready for all challenges.....but then again maybe not!!!!

Zyderbot inspiration

Zyderbot Inspiration

 

So this is what the 2024 version of Zyderbot is based around, a Hummer disaster rescue truck, though for PiWars rescues the design doesn't quite work and we need appropriately sized wheels to cope with obstacles.

Working with one competition robot means that it needs to be adaptable for each of the challenges, and this involves wheel and accessory changes. To make this standard and easier, USB connectivity has been adopted for connectivity of accessory processors and sensors.

The picture shows the optical line sensor mounted on the bonnet and connected by USB. There are a few additions to this for handshaking but the idea is to be as straightforward as possible. 

To make accessories quick-change, they are designed with magnets to hold them in place.

Here is a bonnet for the Pi-Noon challenge with four magnets fitted and the holder. 

The chassis has four corresponding magnets to which the bonnet is attached. It also gives easy access to the battery compartment!

Eco-Disaster

While the chassis and controller are the core essential components, development of the accessories for some of the challenges needs a lot of coding instead. For Eco-Disaster, the camera sensor gives a development image to give reassurance that it's working as expected, and here are two images of barrels, one red the other green. The background colour is red indicating nothing of interest, white is a definite image detection, and violet shows up the reflections in the image due to uneven lighting.

The images look very similar because the sensor has to be instructed to switch between colours and gives a visual result based on what it's being asked to do, the controller only gets numerical information as feedback. The code for this is all in C++ and published on github here.

Writing the code is all very well, but it has to be used by the controller to steer  the robot and collect barrels. So here is our design for the barrel handler.

Two views of the barrel handler to be mounted on the rear of the chassis. It will reach out over the front of the robot during operation and be lifted out of the way when not required. 

There's lots of adjustment in the arm to allow tuning for lift distances but for most operations it will only need to lift a centimetre or so. It reuses one of the earlier Zombie gun mounts, so is over engineered for the task!!!

If you've read one of our earlier blog posts then you'll know there's a very large bearing inside the plastic gear casing which runs very smoothly and gives the mechanism a very smooth action.

Testing for challenges is difficult if the actual challenge course isn't available, so some sort of simulation has to be devised. For the Minesweeper challenge it's paper based.

This is plain wall paper, found hidden in the back of the garage, stuck together and cut to size with electrical tape to mark out the squares. The red square is three sheets of A4 red paper stuck together and to simulate the challenge, the square is picked up and moved to another square. When reading the challenge arena sizes, it's easy to take the space for granted, but this is the only place in the house that can accommodate the arena size, just!!!!

Time is starting to tick away, so probably more pictures of completed robots soon we hope!!!