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 !!!
Medway Makers 
No technical points for Hacking a Nerf gun, depends on how you do it I suppose. Just putting the gun on top, maybe not. But ripping out the inners, creating a mount for the motors and magazine and designing and implementing a launch and aiming mechanism that is more compact that the original gun. It’s taken a few months so I hope it’s worth some points for technical merit!
But yes, it’s hard. Can’t wait to see your custom Nerf gun launch mechanism.
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Well if you are ripping out the inners, creating a mount for the motors and magazine and designing and implementing a launch and aiming mechanism that is more compact than the original gun then you’ve practically redesigned the gun anyway. Of course there should be technical merit points for that. But for those that simply take a gun and, let’s say, get a servo to press the trigger, that is pretty unimaginative. But, perhaps effective.
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