Following the second phase of the Modular Arduino Tank project, this third phase adds a projectile firing attachment to the Arduino base. Inspired in part by the internal design of Nerf toys and a similar turret design by LFK, I set out to create my own custom nerf turret attachment from scratch. Let's get started!
Since I planned on using Nerf foam darts as my projectiles of choice, I decided to borrow design features and measurements from existing Nerf toy guns. Luckily, I had one lying around from my childhood!
Upon examination, I noticed a couple important elements of the design.
Two flywheels wired in parallel to accelerate the darts
The dimension and distances of the flywheels and barrel
The rod that feeds darts into the flywheels
With these features in mind, I was prepared to begin my own CAD model design
With the Nerf toy measurements in mind, I incorporated those important dimensions into my own design to ensure smooth action of the firing mechanism. I also made sure to design a flywheel motor mount with adjustable tightness.
Designing the nerf turret circuit was relatively similar to the 6-axis arm because it used the same two-Arduino setup with a buck convertor. The main difference is that this circuit needed additional motor control for the flywheels, so I used a transistor.
Not much to write home about this time. The circuit was practically the same as the 6-axis arm circuit (aside from the additional transistor flywheel motor control). After soldering the new PCB board, it was just a matter of taking out the old wiring for the 6-axis arm and adding the new nerf turret connections.
Unfortunately, the wiring is still kind of a mess, so I want to learn to make CNC routed PCBs soon.
The Arduino code remained practically the same as the 6-axis arm code that I originally wrote, so the main thing that I wanted to modify was actually my custom app. Since this turret would be aimed by the user, I wanted to make an easier interface than simple up-down-left-right buttons. Thus, I decided to design a virtual joystick for the user to aim with. Finally, I added a flywheel rev-up button a nice red firing button.
This was a particularly fun phase of my modular Arduino tank project! I'm happy with calling this the last part of the project, but there are always new ways that I can add to my modular Arduino tank and improve upon my existing phases. For example, it would be cool to add some kind of laser and range finder to the nerf turret. Additionally, I hope to add some memory functionality to the 6-axis arm so that it can repeat movements automatically. In the meantime, all the code that I created and used can be found here at my GitHub.Â