Fixing the Portobello Police Station Clock
pointinthecloud.com307 points by avidly 5 hours ago
307 points by avidly 5 hours ago
How fun! Once, after climbing around in a dusty old church attic like this, I had to head straight to the airport for a flight. Barely made it on because something in the dust kept flagging as dangerous. They were using a test strip on my backpack and clothing and analyzing it in some kind of machine. Stressful as I was already pressed for time! Finally got a clean test and they let me through.
This happened to me at SFO years ago after wearing a pair of jeans I had go-karted in earlier that day, but I ended up with almost a strip search.
Is the solution to a positive swab really to keep swabbing until negative?
Ion mobility spectrometry is the tech that powers these, and they're VERY sensitive and VERY prone to false positives because it's just looking for ion signatures ("I smell a nitrate/glycerin/etc."). I'm not sure if they're changing modes on the machines between swabs or something, but the machine is a cue for more in-depth inspection, not "zomg I found a bomb". So, some repeated scanning to rule out a false positive or burn off gunk that's accumulated in the machine i.e. we just got a speck of something on the wand or something is gunking up the scanner as opposed to "someone covered in residue that is scary".
TIL! I appreciate the explanation, never considered them to be that sophisticated.
Or to assume it's a false positive.
Shortly after 9/11 I was flying out of Hawaii back to the mainland and I watched the screen when they swabbed my bag. It reported as positive for every single type of explosive (to the best of my knowledge, I was not carrying anything even remotely explosive). The tech looked at the results, said "that can't possibly be right" and waved me on.
In my experience if they test positive the tech will stop and wipe down the machine before trying again. They're highly prone to false positives.
If this was in the US, it's all security theater. Basically if you get flagged, they swab everything in your bag to find what's getting flagged, and if it's legitimate they pass you through, or they keep swabbing you if its just your hands/arms because they also inspect your bag. It's kind of dumb, but also kind of makes sense.
For extra fun times, baby wipes / wet wipes get flagged as explosives in the US when they use the sniffer devices.
The system is also likely designed to have false positives so they can validate that the security people are doing their job. This is more obvious on the x-ray machines but resembles the "can you spot the phishing email" emails that often get sent out in corporate environments to detect people who need additional security education.
I will be the first to join you on "most of TSA is security theater"; the baby wipes are glycerine getting flagged by ion mobility spectrometry. The machines are fast because they just look for basic chemical building blocks, not doing full spectrometry to figure out the whole compound. So glycerin, nitrates, etc. set it off (and someone else's sticky glycerin e.g. sunscreen can gunk up the machine for multiple subsequent people).
Those guys must have a lot of fun with vapes. The liquid is 50-70% glycerine, and you get the stuff everywhere.
This is what I want the internet to be. Great read.
I'm confused… You don't want to read about the newest LLM models on the HN front page all day long, every day of the week? SAD!!
If it helps at all, we put this article in the SCP (https://news.ycombinator.com/item?id=26998308), which is why it's on the frontpage.
We didn't put it at #1 though! That is a confirmation that we made a good pick.
> If it helps at all, we put this article in the SCP...
With the popularity of this post the "SCP" reference made me think Hacker News had some kind of antimemetics department.
Then I saw it was the Second Chance Pool and was sort of disappointed.
You could almost say like it was TIME something like this hit number 1 !
badoosh
....I'll see myself out
If you enjoyed this, here's Fred Dibnah exploring Big Ben and discussing some of the engineering details. https://www.youtube.com/watch?v=Vi1cqR1bJC4
Fred Dibnah was a treasure. If you enjoyed 5 minutes of Big Ben, here's an hour of his day job in heavy industrial steeplejacking - "The Ups and Downs of Chimneys" https://www.youtube.com/watch?v=KK2wF_-yoEg
I just got to tour Big Ben in July when I visited London. The mechanism is an amazing piece of technology and the precision achieved at the time of development was crazy. Also being able to stand next to the bell as it rang was truly an awesome experience.
Fred Dibnah's steeplejacking videos are awe-inspiring and a little bit horrifying. Fred seems like he was quite a character. I definitely recommend watching any videos he was involved with.
Fred is a great YouTube rabbit hole... His "Age of Steam" series for the BBC is fantastic.
https://www.youtube.com/watch?v=kl_UA36ouzM&list=PL2vJ5Cg-wl...
Wild seeing local stuff on HN. My dad used to work in that police station, probably the first (and only) HN story I’ll send him.
I love this. Any advice how to get involved in my local community in a similar way? I'd be so into doing some community project during my free time.
I was heavily involved in the local maker space where I previously lived. The place seemed to attract these kinds of problems. Some people want to fix a VCR, others might want to fix a clock tower (who knows). Being involved there meant being around people who could really do anything, and the community seemed to know that.
Where I live there is a local "optimist club" that does volunteer events every few weeks. Lions club does similar in some towns. Knight of Columbus also (I think they are Catholic church related though so might not be for you). Shriner club, and Masons also come to mind for some cities. Now that my kids are in school there are a ton of organizations that need adult help (marching band, sports...) and people are starting to learn what I can do - I wouldn't be surprised if someone calls me for help in something else.
Of course the above all depends on the exact situation in your area. Some of them are just a social club, and some are not. Some of them have religious affiliations that you may not like. Some of them are good in abstract but you hate the particular people in them.
Depends on your local community, worth considering what spaces there are and just reaching out or showing up.
> The "Status" LED flashes some kind of code - long long, short short short. I assumed the number of flashes would correspond to the time but apparently not. We didn't have time to figure this out before we had to leave.
long-long-short-short-short is 7 in morse code. They don't say what time they tried this or if it ever changed, though, so that's just a hypothesis.
As an engineer i would never think that complicated - morse code?
Couldn't it be just binary
long-long-short-short-short
11000
Which is - to everyones surprise - 24 as in hours.
It's almost certainly this. I suspect the advance button can be used to advance the time via morse code LED flashes and only then committed when you get to the right hour.
Perhaps the long-press commits the hour, which is why it rang once initially.
I used to use Morse to blink out status codes in similar things but I think by the mid-2000s I'd moved from PIC16F628s to atmega328.
I didn't build the chime box but it looks like the sort of thing I used to do back then.
One of the factors for the location I bought my house was the church bell that would ring on the hour from 8am to 9pm. The neighbors had the curch turn it off. :(
Maybe you could get this one to do 9am, noon, 3pm, 6pm weekdays, so you get the sound, but not the annoyance?
The battery on that circuit looks very much like a backup battery we have connected to our house alarm.
We moved in to the house in 2003 and that battery died this year, so I would imagine that it is already or will very soon die. That said, if it's a backup battery and the electricity supply is stable then it may not make any difference.
It's a standard sealed lead acid battery:
https://www.rapidonline.com/yuasa-yuvolt-yucel-y1-2-6-valve-...
https://static.rapidonline.com/pdf/18-5207_v2.pdf
Design spec is up to 5 years. The one in the photo looks like it may have a date written in Sharpie on the side. I don't think it's 25 years old though. The "090323" on top could be DDMMYY indicating a battery from 2023.
I agree with the 2023 decode there, but there is still a bit of a puzzle:
If someone knew to replace the battery just three years ago, I would expect they also would have enough knowledge to set the clock itself. Or at least explain what was going on. Maybe this person isn't connected with the building anymore. But I would expect the new owners would be able to contact the old owners for help on this instead of sending a generalized call for help.
I would GUESS that someone tried figuring it out in 2023 and replaced the battery as troubleshooting. If it were me, I'd probably do the same then stop when I hit a wall so I didn't damage it further. I don't wanna be the guy who damages a 100+ year old public clock
I could just hear the clockmaker James Martin calling me a butcher in his disapproving manner
Could also be YYMMDD In most of Europe it would be DDMMYY - but seeing how the English still measure stuff in feet and inches I wouldn’t be surprised if they have some illogical way of structuring the dates as well
YYMMDD is standard(ish) ISO 8601 - the new versions of the spec require a 4 digit year but older ones allowed it, and ISO 8601 is also commonly used in manufacturing.
YMD is Sweden or Hungary. MDY is US and pre-1960s UK. YDM is Latvia. DYM and MYD are up for grabs.
Next time you're in Baltimore, be sure to visit the Bromo Seltzer Arts Tower where you can see its gravity-driven pendulum clock. It's a beautiful mechanism with a very specific claim to fame: "The clockworks is the largest four dial gravity driven non-chiming clock in the world with the magnificent 24ft dials."
https://www.bromoseltzertower.com/about/virtual-tour
(The elevator motors are also up there so there's a lot going on.)
What a lovely blog in general: some really fun retro-computing projects, written up in a very thoughtful, human way. Feels like a throwback to the earlier hacking spirit of the internet. Thank you, Colin: your "experiment with writing" is a success as far as I'm concerned!
Send it to Big Clive with a felt pen enclosed.
Genuinely underrated way to understand circuits. When I was younger and dumber I thought his practice was a bit silly, but man, it really is king.
For someone who is not familiar with that person/channel, what is that way to understand circuits?
Such a pleasant surprise to wake up and see my hometown at the top of hackernews!
There's a Reddit user who posts in a car repair subreddit about his work repairing bell-tower equipment. Very cool.
Was just reading one of his posts earlier while having lunch, only a few miles from that very clock tower, the one in the post here. Other side of the capital!
> Written on 11th April
> I had hoped we could do a "test" by letting the clock chime thirteen
What in the Orwell
Ahh this made me like the internet today, thank you
i wish i could fix The Sun clock on Broadway and Chambers
it's literally kittycorner from City Hall, and hasn't been running for a while...
i'd do it for free if i knew who to even bother about getting up into it
If you like old buildings, clock and bell mechanisms, or rigging, there's a fascinating series of bell tower repair videos on youtube:
https://www.youtube.com/@DingDongitsthebellguy
He also posts on reddit under dingdongbellguy
This sounds like such a fun project, especially to share with like minded friends.
I want friends like that!
Does it work on a gear and pinion principle or an AC synchronous motor?
Obviously, the next logical step is a Home Assistant integration.
"a circuit board which definitely was not from 1877" ;)
Gorgeous building and a nice wee pub across from it! A couple of friends of mine used to stay not far from there.
I've half an idea I did some networky stuff for the Community Wardens probably around the time that chime box was fitted - if you see anything marked Alvarion or Ceragon, it's probably got my real name on it somewhere.
I'd love to poke about in there some time, maybe if I'm down in that part of the world I can jump in and volunteer to help too.
One of many old clocks in Edinburgh that needs fixing. The one on the Balmoral Hotel had to get a lot of work done.
There were three identical street clocks in Edinburgh that the council there have tried to remove. They succeeded with the one at Tollcross.
I dunno if setting the time counts as fixing...
sure it does. the mechanism was no longer functioning properly. and its a repair even moreso considering the unknown nature of the system.
sometimes you get paid because you know things, sometimes you get paid because you know how to figure things out.
Yeah I repair old cameras these days. The amount of cameras I've fixed by just poking at random stuff until it unjams is surprisingly high. Even more so the number I've "fixed" by just replacing the batteries.
[dead]
They don’t seem to be in contact with the people who actually fixed it.
Seeing the number of holes in that ceiling I really am concerned that the floor the clock is on is the same as the one with the holes, and I would advise that you secure the floor if you return to the attic.
There's a non-zero chance the "floor" is just plywood laid across some of the beams and the holes are from people missing the beam in areas there's no plywood
The ceiling is fixed to the underside of the joists, the attic floor is fixed to the top side.