Raspberry Pi Zero 2 W: slides and thermals

2 out of 4 cores burning, 32-bit mode: time to overheat = basically never

Slides from last night’s talk:

It’s impossible to have a Raspberry Pi Zero overheat unless you overclock it. That’s why you don’t get any cases for it with fans or heat sinks. The quad-core Raspberry Pi Zero 2 W, though, has the potential to do so. Here are some numbers:

  • Used official case with lid fitted: increases SoC temperature +3 °C over free air
  • Test – CPUBurn: https://github.com/pmylund/cpuburn
  • Tested 4, 3 and 2 cores burning in 32-bit and 64-bit modes: time from idle to throttling (80 °C) measured
  • GPU overheat not tested.
line graph of cpu temperature against time. Temperature rises sharply from about 47 degrees C to 82 degrees C in around four minutes
All 4 cores burning, 64-bit mode: time to overheat = under 3½ minutes
line graph of cpu temperature against time. Temperature rises sharply from about 47 degrees C to 82 degrees C in just over four minutes
All 4 cores burning, 32-bit mode: time to overheat = just over 4 minutes
line graph of cpu temperature against time. Temperature rises moderately from about 47 degrees C to 81 degrees C in around seven minutes
3 out of 4 cores burning, 64-bit mode: time to overheat = just over 7 minutes
line graph of cpu temperature against time. Temperature rises slowly from about 47 degrees C to 81 degrees C in around ten minutes
3 out of 4 cores burning, 32-bit mode: time to overheat = 9½ minutes
line graph of cpu temperature against time. Temperature rises very slowly, reach 70 degrees C in 40 minutes and then only rising very slightly to about 73 degrees C in the entire run time of 3 hours 20 minutes
2 out of 4 cores burning, 32-bit mode: time to overheat = basically never

Unless you’re doing things that might indicate you should be using a bigger computer, a Raspberry Pi Zero 2 W won’t overheat and doesn’t need any form of cooling. If you’re overclocking, well … it’s your choice to have cooling equipment worth more than the computer it’s trying to cool.

Directing, 2003-08-14 Toronto

A woman in business attire stands in the middle of a downtown street. It is late afternoon on 14th August 2003, the first day of the blackout. She is facing west along a street with streetcar lines: her shadow from a beam of sunlight from between two buildings is prominent behind her. Her dark jacket is folded over her left arm, and her right arm is extended in a Stop gesture. No traffic is visible, but there are many pedestrians visible behind her
Directing, 2003-08-14 Toronto

Not a great scan, but it’s a photo I thought I’d lost forever.

Taken in Toronto on the afternoon of the 2003 blackout, I was struck by the way she directed traffic in the middle of the intersection.

(as previously shared on mltshp and subsequently to twitter.)

The Yonge & St Clair Autoharp Guy

This guy sets up on the SE corner of Yonge & St Clair most afternoons, and plays endless variations on the above recording. He’s playing an autoharp with the chord bars removed, and run through a homebrew battery-powered amplifier with much reverb and distortion. A bunch of the burbly noises are 8kbit/s voice recorder artifacts from my phone.

Although the themes seem repetitive, I don’t think they repeat exactly every time. He seems to be in a happy place playing them.

WindShare: a stellar investment, a gallant icon

Update: now posted on the Friends of Wind Blog: Windshare: A stellar investment, a gallant icon.

I’ve never regretted my investment in WindShare. When I heard about the plan to put a wind turbine at Exhibition Place, I’d been in Canada for less than a month. We didn’t even have a permanent place to live when I put down my $501. I knew, though, that it would be an investment in the future.

Five hundred bucks seemed quite a bit of cash back then, but these days, it’s less than a flight to anywhere. It’s less than a weekend mini-break. It’s a couple of month’s car insurance, or worse, a car maintenance bill which I wouldn’t even grumble over now. No-one ever expects a car to appreciate after you’ve had the shocks redone, so in the same way, I don’t feel bad about my investment in WindShare not having a financial return. It’s had a much more rewarding return than mere money.

Sure, the initial offering indicated that we were supposed to make a reasonable return, what with the deregulation of the Ontario energy market. You don’t remember that? When the Conservative Ernie “Odo” Eves administration deregulated the market back then, you may have blinked and missed it. At the first taste of $100 power, the deregulation was cancelled, because market forces must always take second place in this province to re-electability. Poor Ernie; we almost saw his like again …

WindShare was supposed to have at least two wind turbines, which would have helped the return to members. For $REASONS, the other one didn’t happen: bureaucracy, lack of suitable turbines, fun with the TPA, lack of headroom from the island airport; any/all/some/none of the above can be cited. We were also supposed to export the model to a community-owned wind farm, but that didn’t happen. The province decided that any and all transmission and distribution near the Bruce was off-limits to all but the eponymous power company. So it goes.

Because of my wind power experience in the UK, I handily got on the inaugural board of WindShare. We campaigned for members around the city. We spoke to anyone who wanted to listen. We built the thing because we believed in the statement we were making. We didn’t hide our pride: we put the turbine where it would be seen by millions every day. If we could’ve put it on the lawn at Queen’s Park, we would.

We even sourced as much of the turbine locally as we could. The tower was made in Ajax. The blades were made in Huron Park. If there had been FIT Domestic Content rules back then, we would’ve aced them.

Now, not quite everything went swimmingly. A few weeks after construction, our vendor went bankrupt. A robust service agreement with a vendor is key to a wind project’s success. With the incredible support of WindShare’s partner in the turbine, frequent visits from the former service tech, a great local electrical service company, and hours and hours of work from dedicated volunteer members, we kept the turbine spinning. Try that with a nuclear plant. Actually, on second thoughts, please don’t.

We also had a slightly smaller set of blades than we’d ordered, having been promised longer ones by the now-defunct vendor. This meant we had to derate the turbine a bit more to avoid challenging operational conditions. Every year at CNE time, we’d lose comms to the turbine as one of the carny trucks would inevitably take out the overhead phone line. We fixed that one.

Other problems cropped up, too. The inverter would get a bit warm in summer heat, and go for a siesta. After building an effective cooling system, the inverter chugged along for a few years until it needed to be replaced. It was interesting working in Canadian generation back then; run-of-the-mill European power electronics were seen as weird new-fangled voodoo in Ontario. As we have lots of wind and solar now, IGBTs are no longer a source of IDKs.

Our wind resource wasn’t quite where we thought it might be, either. ExPlace has a lovely clear fetch across the lake, and historical data from the island might’ve indicated that. Who knew that most of the wind would seem to come over from the city, fuelled by the urban heat effect, and turbulent as all-get-out from chasing through the buildings? Well, we do. With ten year’s hindsight and operational data, that is.

So this turbine — little, (sometimes) broken but still good — what did it start? Well, it lead to the idea of community sustainable power in Ontario. It lead to the abolition of coal power in the province (which, if you can remember the acrid yellow goo that passed for air downwind of Lakeview, you’ll appreciate). It lead to the world-leading FIT program, driving the development of Ontario’s wind and solar industries, which as the last election shows have the overwhelming support of the people of Ontario. It also lead, on a personal scale, to my last decade’s employment building this Province’s sustainable energy base.

So when I see the WindShare turbine — whether fleetingly, from a GO train, or at extreme length when stuck on the terminally gridlocked Gardiner Expressway — it still makes me smile. We built an icon. We built careers then unknown to the province. We built hope. And from that, the return on satisfaction is better than any deal you can get on Bay St.

the happiest sound

Click image for sound [mp3].

That’s the rapid clatter of chopping up Kothu Roti at Amma at the end of our street. You know that tasty spicy food is imminent when you hear that sound. I’m really pleased that Amma’s back under the original management. The other proprietors just didn’t care as much about their food.

My very standard bicycle is not a standard bicycle to the city

I have had a nice BASIL basket on the back of my bike:

With that, it has had all three of Syd’s requirements. But there’s a problem; with the basket on, it doesn’t fit into my bike locker:

These Cycle-Safe lockers taper down to a narrow point, so basically anything other than a stripped-down bike won’t fit. The city says of the lockers:

Locker dimensions
The space inside of a locker is approximately: 1.2m (4 feet) high x 1.9m (6 feet, 5 inches) deep x 0.9m (3 feet) wide at the door and narrows toward the back of the locker. Most standard bicycles will fit inside. Longer bicycles such as tandem bikes or some recumbent bikes will not fit into the lockers.

“Most standard bicycles will fit inside”? Grah. If there’s something more standard that a Dutch bike with a basket on the back, I don’t know what it is. I have to go back to my makeshift solution — a too-tall basket lashed on with bungees — and deal with it biting my bum as I ride. Sigh.

What if you build it, and they leave?

City Hall is currently tearing itself apart over transit. You’d think that in a city with a downtown that’s pretty much gridlocked for three hours of the day, the answer to the transit question would be “More please everywhere”, but in this precious city, it’s less than that.

We have a mayor who is obsessed with subways because he thinks they’re fast and will keep the automobiles running. Unfortunately, Toronto is a big sprawly city with less than infinite cash, so we’re not going to get subways everywhere. Our last venture into subway building — the Sheppard line — has been a bit rubbish, running a stubby distance to nowhere in particular, and being quiet enough that you can always get a seat.

Though I live in Toronto, I’m originally from Glasgow. Glasgow has a subway; in fact, it’s one of the world’s oldest. It was opened in 1896, when Glasgow was at the height of its “Second City” fame. Glasgow made the ships and trains that maintained the empire, and trained the engineers of the world. We were pretty hot shit at the time, and we had a bunch of workers we needed to get around every day from the shipyards and offices of the city. Lots of people moving in to work. Ergo, subway!

Just one problem: cities change, subways don’t. Even though shipbuilding was never a hugely lucrative industry (according to my grandfather, who worked at John Brown’s, they never cleared more than 7% even at the best times), Glasgow and environs would probably have never thought that its industries would change and contract the way they did.

So what’s the subway that Glasgow’s been left with?

  • The industry has gone, so has most of the ridership. There’s an awkward mix of residential stations and, well, nothing stations. I mean, West St? C’mon!
  • Both of the major rail hubs that the subway serves — Buchanan St and St Enoch — are long gone. I just remember the shell of St Enoch station used as a car park in the very early 1970s, but no trains.
  • Given that Scots were a bit squat in the 19th century, the subway’s not built for 21st century people. I could never stand up in the trains.
  • Ridership is frankly pants; indeed, even Toronto’s Sheppard line carries more people every day than the Glasgow subway. Riders are pretty much now park ‘n ride office drones, students (bored [on the way to uni], drunk [doing the subcrawl; a pint at the pub nearest ever station] or daredevil [the subway challenge]) or huns.

Glasgow used to have quite an extensive tram network. Of course, you wouldn’t know now, ‘cos it’s all been ripped up, but you can do that with street-level transit. Subways you’re stuck with.

Cities and cultures never know when they’re at their height. Glasgow had it going on when it built its subway, yet I’m sure the city planners never thought that the city would change the way it did. At least Glasgow made stuff that everyone needed; Toronto, what do you do that keeps you anchored here?

nice bike facilities

I’d seen that the city had been working on the path over the train tracks at Lord Roberts Wood, but hadn’t seen the completed project. What was formerly a real slog to lift a bike (and especially a sensible bike) up these steps now can be ridden without dismounting. Yay Toronto!

(apologies for picture quality. My Blackberry is in perma soft-focus)

If you want to see how they looked last year, there are some automatic photos from my Canada Day post: sd790-20100701-161516, sd790-20100701-161535, and sd790-20100701-161614. A great improvement has been made.

If I must kvetch (and I must: cyclo, ergo kvetch), the turns in the ramp are just a little too narrow to navigate a bike round. I can make most of them if I crawl round it, but I usually have to dab a foot down.

There’s also no lighting. I’m not sure how welcoming this facility would be to use at night. Also, some of the handrails look as if they should either be welded or bolted in place, but are neither. Some have half-hearted tack welds, but they look as if they were done straight onto the zinc galvanizing so were destined to end badly.

Still, much better than it was.