Glow-balls for a staff

Okay, so I've been getting into one small sector of the flow-arts spectrum lately -- staff spinning, which so far is the only form that seems to have any real appeal for me.  Local folks who know me understand that my true flow art [besides Prius-driving!] is loading trucks and playing Tetris with heavy objects, but that's not something we generally do for idle amusement at social gatherings.  With the rapidly rising popularity of flow and circus arts around the community, often with fire involved, it seemed appropriate to find something related to play with.  While poi always seemed a little too wildly uncontrolled and I never really got the hang of juggling or devil-stick or hooping, there's something about the dynamics of spinning a stick that's always intrigued me.  So I found a random piece of PVC pipe kicking around the house and started messing with it to analyze how some of the moves work, and pulled down a few of the *thousands* of videos out there on the subject to watch and single-frame through parts of for guidance.  From martial arts bo-staff kata to marching band drum-major and baton-twirling to general "manipulation", there was clearly a lot of common ground in the basics.  I even took notes, building a to-do list of stuff to try working on.  As understanding grew so did a certain enjoyment -- it seemed to feel comfortable and flow nicely for me, and the fairly light piece of PVC didn't hurt too much when I would inevitably whack myself with it.  After a while I still felt nowhere near ready to set fire to anything, but wanted *something* to add a little luminance to the play.  Various light-up staff products from the likes of FlowToys seemed inordinately overpriced; I just wanted to bang something together on the cheap.  Perhaps an easier route would be to adapt a set of inexpensive LED poi balls and come up with a way to mount them, and in fact the addition of two-inch-ish embellishments to the ends would make my slightly-too-short practice staff closer to the right length for me.  Amazon offered several choices, so I ordered a couple of different sets to see if one type might be more or less easily adaptable for the purpose.  The first pair soon arrived, amusingly from Magic Matt's Blinkies, and I got to work.

The hollow balls are quite soft and squishy, made from a diffusely translucent material that uniformly spreads light from within.  A simple bridle connects to the poi leash, keeping the ball a little more stable while flying around.  The electronics module itself is little more than what we find in trade-show freebies -- LEDs, an encapsulated driver chip, and a small battery built by stacking up some coin cells. [Thumbnail images link to larger versions.]

The first thought was to simply anchor the bridle loop down into the end of the staff pipe, but I realized that this would let the ball rock a lot over the thickness of the string so perhaps adding two more strings along the other axis would stabilize it and protect the LED module a little better.  I thus wanted two more holes and more of a 4-way harness, but would need to get the thing open to thread all that up.  The module was of course glued into the opening, so removing it involved carefully cutting around the edge and hoping I'd be able to re-anchor it in there in some robust fashion. Here I've got the second pair of holes drilled in one ball and the other one marked up, and some different cord ready to become 4-way bridles.

The inside of the harness couldn't pass straight over the module or it would block and maybe crush the LEDs, so it would have to go around the side.  To help it stay in place it would need a little clamp of some sort, e.g. a little bit of "telco wire" wrapped around both interior strings and anchored down.  With only one clear hole available through the baseplate it would need an additional small one to complete the anchor point, just big enough to pass the wire through.

This is how it would go together -- the inner harness parts safely held aside around the battery box, and otherwise reasonably flat across inside from hole to hole once the module was fully reinstalled.  A nice theory, anyway. 22 ga solid copper premises wire is great for this sort of thing, comes in a glorious rainbow of insulation colors, and can cinch down tighter than most zip-ties.

With the two loops of the new harness equalized up and fed down into the retention system, and cushioning the surface of the electronics the same time, the ball seemed to be on there fairly solidly once everything was tightened up.  The on-button could still be easily accessed. You could even say it glows.

    Nope...

However, this approach was doomed.  I took it outside for a quick spin, and after a couple of drops and leg-whacks things felt much looser and the electronics module had already sort of capsized into the ball somewhat.  The strings pulling the edges of the flexible hole all together like that were only distorting everything and not really holding the ball tight to the stick.  I needed some different approach, and plan B was to try attaching from the other side of the ball. After deciding that machine ringbolts and craziness with wide washers and locknuts was just overkill, I popped by the hardware store for some self-threading ring screws whose eyes were just small enough to fit down inside the 1/2" PVC.

This would need a retention means inside the ball, and since the rubber would be clamped between that and a large washer down against the PVC pipe, it could use to be rather wide.  A little chunk of wood seemed like entirely the right thing, since the eye-screws were intended to thread into wood in the first place.

It seemed beautifully simple.  Both balls got reworked, and more tiny-hole drilling and *two* pieces of telco each seemed adequate to retain the electronics back into place.  This created a possibility of having a darker spot on the outermost ball surface, but staff-spinning is usually viewed from the side so that didn't seem like much of an issue.  It turned out that plenty of light could leak through the module's plastic anyway, so it looked fine.

I had several small chunks of the 3/8" sheet PVC left over from the house job, and knew it would likely hold threads a lot better and be immune to splitting.  It also had a little more elasticity, meaning the screw could thread in with a bit more force and be less likely to back itself out under load.  I cut some small squares and rounded off the side toward the inner ball surface, added some thin foam as an additional squish layer, and assembled again.  None of this had to be run together especially *tight* as the mounting system would pull everything down into alignment, but it had to be strong. This is the successful design -- more stable due to larger bearing surfaces, and can stand up to the knocks.  The electronics got wire-twistied back in and I finally had worthwhile glowey staff ends that would stay put.

This also shows more detail about the attachment method: nylon parachute cord running through the ring and down and out opposed holes in the pipe, drilled on an appropriate slant to mitigate sharp edges in the path.  The cord gets tightened down, pulling the ring and ball and everything behind it down firmly to the pipe end, and lashed around the pipe and bowtied to fasten.  Simple and completely removable when the balls need to come off again.

    Rev two

A couple of days later the second set of balls showed up, this time from SpinballS.  These turned out to be an almost identical design, possibly with slightly better build quality and a different-ish set of blink/fade patterns.  Having found a workable mounting method, I figured it would do okay for this set as well and I had plenty more PVC slab and ringbolts left.  But I wanted to try and avoid coring the entire electronics module out of the bottom, preferring to leave it glued in if possible.

Instead, a vertical slit about an inch long was sliced from one of the original leash-bridle holes to about halfway down the ball, making an opening just large enough to insert parts and work through.  Like modern surgery, minimal incision.  This looks a little obscene, but to drill the screw holes I had to hold a small bit of wood up with a finger to back against the squishy rubber right at the G-spot.  Okay, that was bad.

Once the internal parts were fished around into position and assembled, the slit was simply left open.  Because it's vertically aligned the centrifugal force outward tends to close it, not open it, and once the ball is mounted and in use the slit can't be seen at all.  Squeezing it open slightly lets us peek at the LED module of this second type, which has an additional diffusion dome over the RGB emitters.

    The next phase

So all this was fine and dandy, but on further researching the field of of glow props I began to envision an evolutionary path all of this might be able to take.  I wasn't necessarily about to spring for any high-dollar stuff like the Concentrate line or the very spiffy image staff from Apixeltoys, but having a bit more sweep area lit up than just balls on the ends seemed like a fine thing to pursue.  Clearly, so to speak, one base material would have to be some transparent tubing to build into.  Longish shopping-trip story short, Amazon is a great source for so many things, including sturdy polycarbonate tubing and a wide variety of cheap blinkie-toys that can be torn down for their parts.  The sporting-goods market has developed some very grippy types of soft-feel tape for wrapping around bat and racquet handles, also ideal for making center grips for this sort of thing.  With relatively modest investment and a bit of engineering and assembly time, these things could readily come together and form an improved design.

I was away from my home workshop at the time but had brought some parts and materials with me, and managed to make do with the rudimentary tools on-site where I was staying to put an early revision together.  It totally looked like a homebuilt bomb.  Two clusters of RGB LEDs to point down into the tube, now lined with some white foam and sort of an interesting glittery sheet of diffusion material, and one more cluster would light the ball on the end.  Everything was fastened to a bit of 3/4" dowel, which fit perfectly inside the 1" OD polycarb tube and the ball and everything else simply got screwed together from three directions.  A bit fiddly to fit up, but fairly solid once snugged together. The little black button-switch could be activated by simply pushing in on the squishy ball at the right spot over it [later sharpie-marked at each end of the staff].

For a total crock that I thought would be very fragile, it took its share of whacks over the next couple of weeks and seemed to not only survive but also impress quite a few people when in play.  To get an idea of the visual dynamics I shot a short video   [1.3 Mb]   of the two or three simple patterns from the blinkie-driver.  The LED cluster spacing and spread turned out better than I expected, and you could almost believe that it's a commercial product. A subsequent modification of this, for the sake of robustness and a more practical energy source, could have a simple sprung holder for an 18650 lithium cell which fits quite nicely inside the tube with just enough room for small wiring to get past.  Given that the three little button cells in the white box powered this rig for five or six evenings of healthy activity, a charged 18650 would probably last for *weeks* of frequent entertainment.       *   *   * But that's not where the evolutionary path headed.  See the next chapter for what happened next!