In short, coz back in Vegas:
Burning Man – I was aiming to survive and I succeeded. I’m told this year was particularly hard. There was lots of this:
Highlights being camp mates, surprise tackle-hugging Kiwi, the Temple of Mazu burn, the deep playa, and all the pretties. Low points being the brutal dust storms, the heat, and the wind.
As for my LED projects:
- The Mitochondrion lasted long enough for plenty of spinning and I didn’t see a better glow staff out there. Strips slowly failed, until only one of the four was working, at which point I put it away. Lesson: rebuild the power architecture to run strips direct from the batteries, no UBECs.
- The Too Bright Hat was still working by the end, but the battery life slowly dropped from five hours to one. Playa dust is conductive enough that the isolation from the strip power supply to ground dropped from unmeasurably high to 30k Ohms. Lesson: lacquer the traces and seal the strips.
- LED Strip Drivers: Bombproof, except for the switches. These were not dust proof. The two drivers that sat in people’s pockets were fine;the three on people’s bikes died. Lesson: Seal against dust, even if that’s just a ziploc bag.
When I get home, I’ll do detailed write-ups of the Hat and LED strip drivers. For now, we have to wash and then fly a fair chunk around the world.
…or something like that.
I got bad culture shock in SF (and still have more to write about that).
Then we went to Vegas. Oh Jesus.
So now we’re going to Burning Man…
Best part of Vegas was chilling with an old friend who works here. In her pool, in the ‘burbs.
Oh, and if you need to contact me, it’ll have to wait.
…after a Vegas birthday that took in two circus shows, one training session, and one visit to Walmart – it is connection that I value, not spectacle.
Hence I am delighted by this present from Andrea, helped by Shyamtara, from a photo of me spinning the Mitochondrion Mark 4 at Kiwiburn in 2013 by Kellective.
I shall be wrapping myself in this at Burning Man.
We caught up with a wonderful surfer/aerial friend at some cafe down by Ocean Beach. They had toast, apparently causing everyone to blame the techies. In their defense, it was very good toast.
It was like this:
As Andrea says, “you never see that the other way around – surfers carrying their skateboards”.
Saw sand dollars and a syringe on the beach.
Caught up with another lovely friend and went to the cafe at the de Young art gallery. It is entirely clad in bronze, because someone had too much money.
On the wall of the de Young was a huge copper slab ten foot tall listing their major donors. I could try to claim this as a piece of art that asks questions about the place of Art in America, but I have enough culture shock already.
SF looks like it does in the movies. The cultural presence is such that, even from far away as NZ, you kind of know what to expect, or at least there’s a pre-existing set of stereotypes that mediate your experience here. For example, the vegan cafe in Berkeley that’s full of hippy attitudes, the eye-wateringly expensive art gallery in the park, the white homeless people ranting about spirituality, the black homeless people giving you the side-eye.
The trick is going to be getting past that. Or is that the reality and does SF just have a global cultural presence because that’s where so much global culture comes from?
Incoherent jetlagged thoughts from Oakland:
SF is biz jets and crappy public transport.
Time from getting off a plane to seeing a hand gun: less than two minutes.
Hipster mac and cheese?
Sunny parks as lounges.
Lots of homeless people, mostly black, mostly not begging but just hanging around.
Drivers stopping for pedestrians and lots of bike parking.
This American flag towel wasn’t American enough, so they added an extra American flag in the eye of the eagle:
My alert for “happyinmotion” has been going nuts, with numerous German women jumping up and down:
Clearly, this is unacceptable, so I’ll be changing the name of this blog to www.52DRph0vtJT9pjoqXzgs0kJAt6McQH6AZpuzH9Tt3aC448i0sk40ci9hna0SBl1V.com.
The 144 LED per metre LED strips are stunning. The LEDs are close enough that they blur into a single bar of light. Sadly, the LEDs are close enough that joining the strips is a nightmare. The pads are tiny, joints are sketchy, the LEDs too close together to get an iron in there, and it’s easy to overheat and damage the LEDs. And I’ve had to make up four 1.4 metre lengths for the Mitochondrion LED staff, requiring joints in each.
So after much swearing and head-scratching I’ve come up with a better technique for joining them – sew them before you solder.
This applies to both NeoPixel and DotStar (APA102C) strips.
First up, cut the strips to leave whole pads. Don’t cut in the middle between LEDs, cut to one side. Yes, this means that the first LED on the part of the strip you are cutting off is now useless, but hey, you only lose one LED. I found cutting with a knife on a chopping board worked for me, my snips are far too large for this. The strips I’m using had adhesive on their backs, I scraped this off. The ends should look like:
Then make up a jig to hold the two ends in position, leaving both sides free. The ends of the strips should just butt together, for reasons that will become obvious. I only have one vice, so I used a clamp and some blocks from the workshop:
The next step is the fiddly one. I cut a length of multi-stranded hook-up wire, stripped the insulation off, and pulled out a single strand. I fed this through the holes in the pads and wove it back and forth. You could just make a simple loop, but that would leave the strip ends free to move and overlap. Instead, I wove some of the loops in a figure of eight pattern, with the strand crossing sides between the ends of the strips. This pattern can be tightened onto the pads and holds the strip ends against each other. Tweezers help. A picture is probably clearer than words, click to enbiggen to make it even clearer:
Getting the strand between the ends is easy, provided you start the sewing at one side of the strips and work across. That way you can hold the strand tight and pull it between the strip ends. Once I’d done a reasonable wrap, I took both loose ends of the strand to the back side, twisted them together a few times, cut them short and bent the ends down:
Now that the strips are held to each other and there is wire between the pads, soldering is a piece of cake:
And this is with a dirt-cheap, no-temperature control, medium-size soldering iron. I’ve yet to have a failed joint with this technique:
1) This technique does require an additional 1 mm between LEDs. This leaves a tiny, tiny gap. When the LEDs are on, I can’t spot the gap. If that isn’t good enough, then you could use the wire technique to overlap the pads directly and tie them together, but that’d require more complicated knots.
2) These joints are still just solder, so I wouldn’t bend them too much. Thick tape on the back of the joint seems like a good idea.
3) I really should write up my bombproof LED driver design.
Driver boxes for the Flying Carpet, Marks 0 and 1. You could call this the march of progress, so long as progress is defined as smaller and tidier:
In fairness, I did the Mark 0 in a day’s rush before Kiwiburn, hence the horrible jumble. The Mark 1 is tidier, but of course building it revealed a bunch of extra tweaks to make assembly easier, like making everything through-hole, adding screw terminals, and shifting the sockets for easier access to the mounting screws. So there’ll be a Mark 2 and I’ll share that design.
The goal is a family of bomb-proof LED strip drivers, in a selection of sizes.
Specs for this version are: Teensy 3.1, level shifter, 34 Watt-hours of Lithium-ion cells, and 15 Watts to run NeoPixel or Dotstar strips. Will run 50 LEDs white and full brightness, 150 LEDs at single colour and full brightness, or many if your patterns are not full brightness. And a solid metal case that you can step on, and locking connectors so the cable won’t fall out.
Or maybe we just like to put googly eyes on all the things. This is the soft case for the hard case for the Mark 0 driver:
Spent today cutting and stacking about three cubes of mostly Japanese Cypress from some friends, with added mahoe from another fried, and mac and pine from our land. This will do for winter 2017, but when the hell did I start making plans that long?
And a shed full of bought pine for this winter, and pōhutukawa cut last year in piles for 2016, and we’ve now run out of space to store and dry any more wood. We were going to get some of the sycamores taken down this year, but that will have to wait until we’ve either burnt what we have in hand or made some more storage. Given we live in the side of a cliff, that’s tricky.
Pictures courtesy of Peter Jennings.
Right then, after a fair amount of swearing, I made the decision that the Mitochondrion Mark 5.0 has some fatal design flaws and won’t be ready for Kiwiburn. Turns out the 144 LED per metre Neopixel strips are a bastard to join and connect to. There’s a variety of ways to do it, none of which will work with my very tight design. Seriously, don’t try to squeeze as much into a one inch tube as I did.
This does mean I’ve learnt enough that the Mark 5.1 should be much easier to construct. This does mean designing and ordering new circuit boards, stepping the power down to 60 Watts not 120 (coz it was going to melt), using more reasonably sized batteries (14500 not 16340), and trying the new APA102 strips with POV and smooth colour fades.
So instead of the Mark 5, we’re bringing something else. It’s a Wendy & Jez co-production and you are all invited. You’ll know it when you see it, but yesterday it looked like: