With our nice four day week, I continued to design the intricate systems on the float, with the main focus on the Battery Holder. This brick of plastic is designed to hold 8 AA batteries. Last year we used off the shelf battery holders, which were nice and easy, especially since we were in a time crunch, however they were not very space effecient. This year we are going a different route. We ordered some battery contact/clip thingys from Digikey, and are custom manufacturing our own battery revolver. While not dangerous, this holder is much more space efficient and also much cooler than our previous design. That being said it is muuuuch more complex. It took me about a day to fully model it, with someone else taking a crack at it before me.

Rendering of the float 3d Model
This is what I have so far in the 3d Model. We are mostly just missing the electronics, which will probably go above the battery holder.

The battery holder works like a normal battery holder. The main body holds the clips which will be soldered, then epoxied in place (I would have preffered screws, but there wasn’t much space). There is then 2 plates on the top and bottom that do double duty of reinforcing clips, and hiding/protecting the wires. These are then held in with countersunk screws (for the sleek flush finish). To make these screws work I tried both tapping the resin test peice, and using threaded inserts to no avail. Unfotunatly the one strongish method I found was essentially using the screw as the tap and forcing it into the hole which I don’t love, but i’m ok with it as it isn’t a critical part and there are multiple screws. The two circle cutouts on the side are to allow for clearance for the anti-rotation rods that have been the subject of too many blog posts already.

Rendering of the battery holder 3d Model
Battery Holder, as mentioned above

In other news the 3d Printers, simultaneously completed prints unattended, after school yesterday, so hopefully they are fully operational again.

{Picture of the 3d printed battery hub}
This is just half of the battery holder as the other side wouldn’t have printed well on an FDM printer. This is the first fully complete print after I rebuilt the extruder last week.

So far the float is doing very well, and we have met/exceeded our september goals. You can find the overall project outline on my partners website, Scott Campbell.