Happyinmotion

If you’re running NeoPixel LED strips off a Teensy 3, maybe because you want to put 180 LEDs on a hat, then you need a level shifter. But which one? The NeoPixel data protocol is high speed and pretty harsh on timing requirements and I’ve had a bugger of a time getting reliable data from the Teensy to these strips. Hence I’ve tested a bunch of shifters. I tried a TXS-0102, TXB-0108, 74HCT245, PCA9306, and a MOSFET based shifter.

The Teensy outputs data at 3.3 Volt, the strips expect 5 Volts. Or rather, the strips might see 3.3 Volts as a digital 1 or they might not. If you want some reliability, then you’re better off shifting the Voltage level up to 5.

Each LED reads the data it needs and passes on the rest, regenerating the signal to nice square pulses, so there is no decline in signal quality along the strip. Well, that’s the theory. In reality, all sorts of weird failure modes can happen.

Anyway, short conclusion from this testing is: use a TXS-0102 shifter if you’re tight on space and running one or two strips, use a 74HCT245 if you’re not or you are running three to eight strips. The 74HCT245 was the only shifter to give perfect performance, everything else had some kind of problem.

Test results and scope pics

Here’s details on my Kiwiburn project – a hat with 180 LEDs, all individually controlled… but to be honest, this was my project for Circulation, back in November. Getting it built was easy, getting it to work took quite some time, but I learnt a great deal. So here’s my design for a portable driver for the NeoPixel LED strips.

Why do this? Before making the next Mitochondrion, it was time to learn some new technologies.

The Mitochondrion Mark 4 (my glowstaff) is not too bad – 88 LEDs controlled by an Arduino Nano. However, it might be pretty but it isn’t responsive or interactive. It just splatters photons everywhere, generating randomly-chosen patterns.

I want more than just random brightly coloured lights. I want emotion, narrative depth, and engagement. That requires a far gruntier microcontroller than an 8-bit Arduino. Something like a Teensy 3.0 – ARM Cortex, 32 bit, about fifty times faster, lots more memory, and only 18 mm wide. And LED technology marches ever on, with Adafruit’s Neopixel strips being a big step up. And all of that is pushing me to use lithium batteries, even if they take more looking after than NiMH.

Thus it’s time to step up my technological game for the Mitochondrion Mark 5. The Hat seemed like a simple project that I could use for learning these new technologies – how to use them and what to use them for. Now that the Hat is working, I’m glad I took this step, because trying to get all this to work for the first time in the Mark 5 would be a bugger. Continue reading 180 LED Hat for Kiwiburn

We can grow maybe a third of the firewood we need on the land we have. Which is nice.

Obviously, the supply for each year depends upon which trees we’ll be trimming or felling. This spring, we got Joe in to trim back the big pohutukawa as it was overhanging the house and blocking the sun. That gave us a year’s worth of wood all by itself.

That’s a lot of bucking and splitting and stacking to do, maybe three cubes? I’m in favour of making this easier and safer, hence my three recommendations for firewood processing: the old car tyre, the bucking stand, and the maul handle protector. Continue reading Making firewood easier

That sign does indeed say “Lord Weston’s windy crack”. Yeah, I dunno. It was certainly howling a gale up there. Further along was a proper shed. Cut for sheddie pics

Courtesy of Camera von Theuns. More at his site.

This is possibly the most relaxed video I’ve ever put together.

Squidsoup were kind enough to let me have a play with Volume 4,096 – a sculpture of four thousand LEDs, in a 16x16x16 cube that hangs in the foyer of the Royal Society of New Zealand.

These patterns are all Perlin noise in HSV-space, with varying rates of change and scaling. And yes, the patterns were generated with Processing and more Toxiclibs.

Filming by Patrick Herd. Music by Christian Dittmann – Planeta rojo. Best viewed at 1080p.

Our snug is, well, snug. That’s kind of the point. But it does mean that the wood burner is worryingly close to the hi-fi amplifier and the shelves. Hence I thought to myself, I’ll make a heat shield out of aluminium sheet. And to make it look pretty, I’ll write some code to generate a pattern and get that pattern laser-cut into the aluminium and it’ll look a lot like every other algorithmically-generated laser-cut pattern, except it’ll be uniquely mine and a project I can take right through from writing the code to screwing it all together.

It didn’t quite happen like that. But we’ll get to that bit.

Everyone and their dog is using Voronoi patterns, coz computational design is the flared trousers of this decade. The patterns are vaguely natural and there’s a wonderfull Processing library called Toxiclibs that makes this easy. Some messing about tweaking parameters gave me this design, which is just as flowingly organic as I wanted, i.e. not much by most people’s standards, daringly lacking in rectangularity by my standards:

I sent that design off to Ponoko for a quote. And then I fell over, coz US$60 for the aluminium sheet, US$50 for the laser cutting, and US$100 for the shipping, coz they don’t cut metal in NZ. I asked some more local cutters and they said a worse price. Errr… no. Instead, I just had some long showers and pondered, until I came up with another way to do it.
Print out the design full scale, glue the design to a sheet of aluminium from the pile in the workshop, and use that design as a guide to drill some holes free-hand:

Round the corners, deburr, run an orbital sander over the surface, tidy up, and it’s done:

Things I’ve learnt from this project:
1) Laser cutting metal is still really expensive.
2) Absolute positional accuracy is still really expensive. If you can design it away, then do so.
3) Per dollar, laser printers are astoundingly accurate pieces of kit.
4) Brushed finishes on aluminium hide a multitude of sins. Orbital sanders FTW!

The IPCC summarises climate change research. The first of their three reports, on the physical science of climate change, is out now. It covers the research since the IPCC’s last report, in 2007. After reviewing about 10,000 papers, the message is very simple:

The more fossil carbon we burn, the hotter it will get. It doesn’t really matter how fast we burn it, but if we dig it up and burn it, then we commit the planet to warming.

And that’s that. You can read the rest of the report if you like, but the single key message is right there.

(Figure SPM.10 from the Summary for Policymakers)

Not me. I’m moving on to the Ministry of Primary Industries as senior science adviser.

It’s going to be the same combination of policy for science and science for policy, with a focus on the role of innovation in the primary sector. And being part of government, rather than an independent NGO, I will be keeping my opinions more to myself than usual.

It’s been a fun (just short of) ten years at the Royal Society. I’m proud of the pieces of advice that I’ve written/helped put together/been involved with, particularly:

2020: Energy Opportunities
Emerging Issues – Ocean Acidification
Geoengineering no replacement for reducing greenhouse gas emissions
Emerging Issues – Virtual Water
Emerging Issues – GM Forages
Emerging Issues – Sea Level Rise
Ecosystem Services in Policy workshop
Emerging Issues – Ecosystem Services
Future Marine Resource Use
Evidence from ten years of research contract management
The Sustainable Carrying Capacity of New Zealand

But been there, done that, and now the future’s going to be different.

Patrick’s put together a write-up of Sigma Mesa, which I mentioned obscurely a couple of weeks ago. We’ve made it onto Hackaday (Taking pictures of exploding wires) and Petapixel (Capturing High-Speed Photographs of Exploding Wires).

I say “we” with a degree of caution. Patrick did most of the work, with HWMNBN contributing timing and charging expertise. I mostly just had conceptual ideas, did some project management, stood around looking bemused, and worked out how to explain the value of all this engineering to a bunch of art and design people. We were aiming for a system that could image ~10 microsecond events using affordable hardware. To do this properly would require cameras that cost $8000 per day to hire, which means you’re only going to do it if you already know what you are doing. Instead we got useful data out of about a grand’s worth of kit, which means you get to play about and discover what might be possible.

It’s been creatively fun, we achieved what we wanted to achieve, and we impressed the people we wanted to impress. Clearly it’s time for a break.

So instead I found myself putting together a detailed plan for the next project. Oh god, this one is going to be awesome…

Yes, ladies and gentlemen, it’s Bruno Latourette.

I’m not sorry.