I was saying to Tom yesterday that it is no wonder so many teams drop out of Pi Wars in the first few months. Pi Wars is hard. There is no doubt about it, they are not called “Challenges” lightly. Over the last month or so I have been designing, redesigning, printing and reprinting parts for the Nerf Cannon. We could have gone down the route that lots of other teams have gone down and hacked a Nerf gun, But we chose not to. Those solutions are not elegant, they look ugly as hell, and are not going to win many points for Technical Merit. We chose to design and build a Nerf cannon entirely from scratch.

This was hard for two reasons. One, it meant having to learn a CAD program to enable custom built 3D printed parts to be manufactured. Our chosen software is Fusion 360 as it is extremely powerful and allows entire assemblies of multiple parts to be constructed with relative ease. I have gone from a complete beginner in Fusion 360 to a competent intermediate user in the last few months and I am now producing complicated multi-parts devices.

The recent iteration of the Nerf Cannon for the Duck Shoot challenge is made of 13 separate parts. Secondly, once a design is constructed, there are then rounds of testing, tweaking the design or even complete redesigns, reprinting modified parts and so on. Perhaps if I wasn’t such a perfectionist I would ‘make do’ with an inferior solution, but I am keen to get it right. All the work is made much harder as the bulk of the technical aspects of the robot build fall on my shoulders. Fitting time in to get stuff done is tricky.

For the maze challenge, we have used the usual ToF and ultrasonic sensors and the robot is solving the maze in a very respectable time. This one was a lot easier than expected.

Next, we are going to be working on a solution for the golf challenge. I have a few ideas in my head and parts are on the way. The Obstacle Course and Pi Noon will need minimal work apart from plenty of practice as these are manually controlled challenges. Although we may program in some automation if time allows.

The Straight Line Speed Test will be a lot more challenging with the addition of the narrow section in the centre. This will require either slowing down when it gets there or a very efficient centering algorithm. Somewhere Over The Rainbow may prove challenging, we have yet to see.

Finally, at the moment the robot is ugly. It is a basic chassis with a spaghetti mess of wires on top. I would really like to design a nice looking chassis where all of the electronics are hidden away. However, time is running out and this will have to wait until last. There are only 11 weeks left until the competition. Tick tock tick tock !!!

The 7 challenges for the 2018 Pi Wars challenge differ slightly from before. There are a 3 autonomous challenges and 4 that are remote controlled.

For the remote controlled challenges we have: Slightly deranged golf, Pi noon, The obstacle course and The duck shoot.

Slightly Deranged Golf

The golf course is the same course as last year but with a slightly less steep angle for the initial ramp. This is a tiny golf course but has a ramp to contend with at the start, plus a 180 degree u-bend with 2 hazards, then another ramp with a moving windmill before the hole.

A lot of people had trouble with this challenge last year due to: a) the ramp, balls came loose from holders, etc. Having a way of encapsulating the ball on any angle would be beneficial. b) the hazards, the ball going down the ramp would inevitably go into a hazard unless you were able to aim the ball at a wall and make it bounce off at 90 degrees prior to the u-bend. The ball has to either kept in captivity throughout the course or aimed at speed towards a wall prior to the hazard. c) the artificial grass, this made traction difficult for robots with omni-wheels or small wheels. Go for tracks or larger wheels. d) the narrowness of the course. Several robots were very large and found navigating the bend tricky. Smaller robots fared better here. e) The windmill. The blades of the windmill were turning and so the ball had to be fired at the hole at just the right moment. Some kind of solenoid or other device to propel the ball is advantageous.

Pi Noon

For this challenge you mount a spike on your robot with 3 balloons attached. The aim is to use your spike to pop the opponents balloons. This challenge is won by a combination of luck, driver experience and robot agility. The robot has got to be able to move quickly and do such maneuvers as spinning on the spot and quick reverses. The driver must be well experienced in controlling his robot. Practice, practice, practice. Ideally find someone else with a similar robot and practice against them.

The Obstacle Course

Again, this course is down to driver experience and robot agility. The course is not known until the day of the competition and you get one and one only attempt at the course. The aim is to get through the course as quickly as possible and attempt every obstacle. Points are deducted for rescues or failing an obstacle. Winning robots were not too large, quick and agile with drivers who had obviously practiced well.

The Duck Shoot

The above 3 challenges are the same as last year (apart from the obstacle course being a different course). The Duck Shoot challenge is entirely new. The aim is to fire 5 soft projectiles at 5 duck targets from behind a line. Most people will undoubtedly go for Nerf Darts and either hack an existing Nerf gun or design a firing mechanism from scratch. Again, driver agility and experience is essential here to aim the ‘gun’ at the target. I like this challenge. It is the first time projectiles have been allowed. Coming up with a nice and reliable mechanism that can fire the darts will be an interesting challenge.

Straight Line Speed Test

The straight line speed test is the same course as last year. However, they have added a narrow section halfway down the course. This is to prevent robots simply hugging the left hand wall and to force a more intelligent way of remaining central. There will be an addition of a white line down the centre so either a line sensor or use of a camera and OpenCV will be essential here.

The Minimal Maze

This is the exact same course as last year with no changes. I think only a few robots successfully navigated the course last year so it is a valid challenge. It is essential for the robot to make its way through the maze as quickly as possible without touching the walls as the times for all 3 runs will be added together. Use of infrared and/or ultrasonic sensors will be required here.

Somewhere Over The Rainbow

This is the final challenge and an entirely new one. The robot is placed inside a square arena and has to detect and visit 4 coloured balls in the correct order. There will be now way to do this challenge without a camera and computer vision code (e.g OpenCV). This will be the most challenging of the challenges in my opinion and will require the most advanced code. I think a lot of people will fail this challenge. It will be interesting to see how people fare on the day.

There are an additional 3 challenges where points can be obtained: Blogging, Technical Merit and Artistic Merit. It will be worth devoting some effort in these areas where possible to get a few extra points.

So there you have it. The 7 (10) challenges for Pi Wars 2018. I really like these challenges. They are a combination of difficult and fun. There will need to be some very careful thought and planning on some challenges, especially the line test, rainbow and duck shoot challenges in my opinion. Planning, designing and building for the challenges are already underway. Keep your eye on this blog for details of our progress leading up to April 2018.

We have just learnt that our application for Pi Wars 2018 has been accepted. We are, of course, very happy about this. Especially as we have been working on a robot for a little while now and it would have been such a shame to have done it all for nothing. This will be our very first Pi Wars and, quote rightly, we are entered in the Beginners section. Although we are a Makerspace, we do not have an official space, meeting up in members houses instead. Although 2 members have a 3D printer of their own, Medway Makers as a group does not. We also do not have access to laser cutters, lathes or any other specialist equipment that a Makerspace or Hackspace might have. The Pi Wars team is therefore made up of enthusiastic individuals putting their own time and effort, plus use of their own personal equipment, into the project to make it successful.

Now it is time to review the challenges and decide how we are going to approach each one. We will, of course, keep you updated on our progress.

So, earlier in the year Medway Makers decided we would form a team to enter the Pi Wars competition in 2018. Mike McRoberts gathered a bunch of people who expressed an interest at one of the regular Medway Makers meetings.On that day there were 7 people who wanted to be part of the team. Since the we have had several meetings to work on and plan the Pi Wars robot and unfortunately only two people keep turning up; Tom Sparrow and Mike McRoberts. So, the team is now a two person team. Despite it being only two people, those two people are very enthusiastic and have the skills and necessary to design and build a great Pi Wars robot. We also now have Mike’s 3D Printer at our disposal and so can print bespoke parts if required.

Without knowing what the 2018 challenges were going to be, we decided we would design a robot capable of tackling the 2017 challenges, as at least then it would require fairly minor (hopefully) changes to the design once the challenges were announced. We decided on a mid sized chassis and four wheels. We discussed tracks and six wheels but decided that 4 wheels seemed to be popular on the majority of successful Pi Wars robots and was therefore an obvious choice. It also kept cost and complexity to a minimum.

We have, since then, tried out various wheel and tyre combinations, as well as several motor controller boards and batteries. We seem to have a good combination of battery and motor controller now, but would like to try out a few more wheel and tyre designs, perhaps 3D printed versions.

The chassis will, I am sure, go through several more iterations before we are happy with it and then there are the design and coding challenges we will face once we know what we are up against in the 2018 competition. Watch this space as we discuss our progress in designing and building this robot.

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