Finally got enough going on this thing to show it. This uses a Teensy 3.1, 12m of APA102 (648 pixels total), a 9DS0 accel/gyro, and lots of fun hours tweaking animations.
Some of the animations are motion reactive: either they change color palettes based on how the staff is being held, they become more “crazy” when the staff is bumped, etc.
I’m happy with where it’s going, but still have a lot of work to do!
It weighs 4lbs, is 6’ long, runs on 17Ah of LiPo batteries, which gets me ~8+ hours of runtime not at full brightness (which, at night, is way too bright).
This is essentially the hardware, with a few small tweaks going into prototype 3 (carbon fiber tube to shave 1.3 lbs of weight, low profile copper tape to keep wires outside from bulging). From here on out, it’s all software and coming up with fun and cool animations!
Nice! Building light sticks like this back in 2010 is part of how FastLED got started (on the nightmarishly terrible by today’s standard hl1606’s). I’m glad to see that the tradition lives on
Man, I need to get back in the game. I’ve been doing so much 3D printing stuff, going into the metal territory now, and sadly ignoring my electronics. But it’s coming. I had to revive my POV sticks last week for a presentation, so that pushed me to re-open a bunch of files I hadn’t looked at in a while. Time to redo several things and get working again.
@Gabriel_Schine , question for you: since you are already encasing the entire tube with heat shrink, twice, how about impact resistant polycarbonate tube? Would be cheaper than carbon fiber I think. A 1" OD, 6ft length of carbon fiber tube can cost upwards of $150 where the same thing in polycarbonate would be $15 to $30 depending on how thick you want the wall to be. And the heat shrink would also add more protection and rigidity. I use polycarbonate tubing for my POV sticks and it’s been working well.
@Ashley_M_Kirchner_No the six foot length of polycarbonate (I have one) is so flexible I dismissed it outright. Using the aluminum I had to heat-shrink twice, as the aluminum rod was used as the ground bus for the whole staff. I was hoping now to heat-shrink only once, so I guess I’m not sure how much rigidity that brings.
I’d love to look at your POV code if that’s an option. I’m moving into that space now, as soon as I get my math right for the various sensor readings.
Ah I didn’t realize you were using the rod itself as a conductor. Yeah, in that case polycarbonate won’t work, but then, neither would carbon fiber … So you’ll be running a ground wire instead. We can talk about my code whenever, just send me a message so we’re not cluttering this space.
Thanks, @Robert_Atkins :). That’s where most of the real works happens! But yeah it’s easy to forget to document, especially when you just want to get it done…
I see. That looks pretty good. It’s an interesting approach but I worry that putting the LEDs on the outside will mean that they get damaged quickly. They certainly would with my butterfingers spinning style.
I found polycarbonate tube is flexible, but the thick walled stuff is acceptable (my staff is 32 mm OF, 3.2 mm wall thickness.) Then there is the fun of fitting all the gubbins inside such a small tube…
Progress at my end is I screwed up the last PCB order, wasting a fair few weeks. Another order should go off to OSHPark tonight.
I was wondering about that. I have had a POV “levitation wand” design spinning around (ha!) in my head for a while and I was thinking of doing it with the strips stuck to the outside of a cardboard prism, inserted into a polycarbonate tube of just-big-enough-to-fit diameter. If the triangular prism was aluminium (or wood?) would that provide enough stiffness @Gabriel_Schine ?
@Jez_Weston I’m finding that the polyolefin shrink-tubing is pretty great - stiff but absorbent. So far I haven’t had any LEDs fail (except for the one in the video that’s alway red, but that was broken beforehand). I’m trying to beat the snot out of this thing to see if it truly can withstand real-world use. What have you crammed into your custom PCB? I’m curious about this.
@Robert_Atkins probably. How long is your wand? My polycarbonate tube is 1" OD, and at 6’ long, it’s downright bendable. At 2’ long, it’s pretty darn stiff. So you could probably find a sweet-spot with a larger OD tube of the right length to not require something really stiff on the inside (and then also save on weight).
@Gabriel_Schine The current spec (Mark 5.2) is a Teensy 3.1, twelve 14500 Li-Ion cells, four 1.4 mm 144 LED APA102 strips mounted on an aluminium spine, a 15 Watt UBEC for each strip, LSM9DS0 motion sensor, a bunch of FRAM, and some other gubbins. All inside a 25.4 mm ID tube. It’s somewhat packed.
The Mark 4 has survived three years of festivals and dance parties, to the point where I’m happy to let munters play with it. I’m aiming for something equally bombproof.
Sheesh, TWELVE batteries (I presume 6 in each)?? Have you considered switching to 18650 power cells? 20A burst mode. I run a total of 192 LEDs off of one single 18650 for several hours. I know you have three times as many LEDs in your setup, but three of those powercells would take care of that, heck add a 4th one for a buffer.
@Jez_Weston , did you consider copper tape and/or grounding strap as a flat conductor? Or still not enough room? Also, if you really want to blind people, and are building custom boards anyhow, the Murata OKR T/10-W12s are tiny and will knock your 15W UBECs out of the park.
@Robert_Atkins I’ve been experimenting with same, fitting 18650’s inside a 3/4" tube. Copper tape is flimsy and will break, and a single lead of grounding strap will just fit. It’s incredibly tight though and annoying to work with in general.
I use 1" OD, 7/8" ID polycarbonate for my POV poi. I fit an 18650 with a 10k thermistor along side and one wire lead (from the furthest end). However, I suspect 1/16" wall is too thin for what you’re doing.
