Mini-Hall Joystick Refinements

Refinements of the Mini-Hal Joystick.

The basic mechanical design prototype was completed. But it's not done yet. Just received the PCBs and have to now consider the details of the wiring, assembly etc. I do have some idea about how to wire them, with electro-magnet wires, or 30+ gauge wires (that's why the 4-point star shape of the inner components. Now I also have to consider how to easily assemble and make this stuff... for you.... and me.

There are already a lot of design details considered for you, and me, to make them at home, preferably with just a 3D printer and some hand tools, avoiding using CNC mills at all costs.... For instance, one of the problems that I have to solve is how to make the latex "spring", easily. Take a look at the 2nd picture. That's the set of jigs to make the latex membrane "spring." The basic problem is that I have to 3D print 2x concentric rings (one OD=1/4", ID=2mm", and one OD=19.31mm, ID=10.34mm) and tie a piece of latex membrane onto the two, perfectly centered, and evenly tensioned. That.... is not an easy problem to solve. The trouble is the inner ring is so small that you can't do it by hand. You have to have jigs to hold the rings and the membrane eventually tensioned while you tie and twist a piece of aviation safety wire to tie to membrane to the rings. The left hand side is the jig for tensioning and tying the outer ring. And the right hand one is the jig for tying the tiny ring inside the larger ring. Both must be perfectly evenly tensioned, and the tiny ring must also be perfectly centered. Otherwise, when the stick is put in, it tilt to other side or the other.

The 2nd picture shows you that it's definitely repeatable. There are two working mechanical prototypes now. The left hand one is printed with PLA on a Bambu X1C, and the right one is printed mostly with PA11-CF on a Prusa Core One. The LHS one is the first mechanical complete prototype. The RHS has some refinements. For instance, the LHS has an integrated filler with the bottom cap, and this could be a problem for wiring. The RHS has a separate filler, probably no filler because I was able to shorten it by 1/4" to 3/4" while eliminating the filler (just need to wait for the shorter 100x bronze sleeve bearing I ordered; had to order 100x to justify the s/h costs). Also the RHS bottom cap has printed knurling for easy screw on.

The inner core on the LHS is a 3 piece printed parts, one as the sensor seat/shaft fixer, one as the optical sensor housing/plunger, and one as the dome spring seat. There is no gimbal. Now, the RHS has exactly the same 3 parts, but the sensor seat has 4x wings extended. This is to serve as the guide for the other two parts against their rotating around inside the bronze sleeve bearing (not a problem if they rotate a bit, but could be a problem when fragile wires are going through). The 4x wings are also there to protect the wires. The M2 screw serves as an adjustable optical gate. Now, the whole core can be assembled and adjusted outside the sleeve bearing, and inserted as one unit. I will probably design a 3D printed jig for the adjustment... you know, hook up an oscilloscope (a digital multimeter if you want) to the electronics, and adjust the optical gate to my liking. All these parts are 3D printed (except the off the shelf metal parts). They come out of the 3D printer(s), the support material tore out, deburred, and lightly sanded.

Note that, I consider this latex membrane spring a consumable part. So, it's important for you and I to have many spare parts.... thus having the jigs to make it easy to reproduce them is very important. I was able to make a satisfactory membrane spring that reasonably centered the stick without a jig.... after many failed attempts... that's just not very repeatable. So, I spent months designing and prototyping the jigs. They looks simple... but it's actually several months of efforts. I will have to make a video on how to use the jigs to make a membrane spring someday.

Next thing to do is the electronic integration. I don't expect any problem, except maybe the routing of the wires.

[Edit]

The next picture is a "plate" of a Mini-Hall Joystick 3D printed parts.