For this week’s (two week) assignment, I attempted to replicate the strum bar from the original Guitar Hero controller as part of my personal project to create one of these controllers from scratch. I first started by making sketches for each of the four prompts and doing the two preliminary 3D models. For modeling, I chose to go with Fusion 360 as I’ve used other Autodesk software before and also because Fusion is more geared towards mechanical design which I knew would come in handy later when designing the moving parts of my strum bar mechanism.
After I had finished those initial steps, I started trying to decide how I was actually going to implement the switch mechanism. I first thought of having a separate spring that would cause the bar to bounce back into place after hit, but decided that it would be complicated for my first go with designing my own parts. Instead, I ended up using limit switches that had a lot of bounce and travel to rebound the bar instead, which simplified the design greatly. I bought some limit switches off Amazon and then used calipers to measure the dimensions and then modeled in in Fusion. I then created slots in the side of the original housing I had created for the strum bar to mount the switches and refined the profile of the strum bar itself to make it more ergonomic.
At this point I decided I was ready to try printing. The first three attempts were complete unsuccessful, with two prints failing due to the printer malfunctioning and the other not having enough filament for it to complete. Finally after managing to get a print to complete all the way, I realized that I had miscalculated the tolerances for the distance between the bar and the switches and there wasn’t enough contact for them to be actuated. Because I would have to reprint the whole thing, I decided to scrap the excessive housing and instead mount the switches on two end caps instead to save plastic and print time. Unfortunately, after printing the new version the holes for mounting the strum bar somehow were extremely tight, which may have been due to temperature fluctuations. I did one final print with a slightly increase hole diameter and it ended up fitting just right.