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Posted by avidly 6 hours ago

Fixing the Portobello Police Station Clock(pointinthecloud.com)
338 points | 75 comments
walrus01 38 minutes ago|
My first thought was it'll be a lot easier to maintain if they put some sandpaper-like grip tread on those wooden ladder/stair steps. It comes in self-adhesive rolls, you peel and stick. Huge safety improvement for very little cost.

Without modifying anything intrusive to the mechanism, a cheap way of monitoring to make sure it's still running OK would be to install a low cost PoE IP camera mounted in such a way that it's aimed at the gear mechanism, then feed its video into something like Frigate. As cheap as $75 for a camera, some cat5e cable and staples to take the cable to where you need it, and an old desktop PC (plug it into anything that gives it a DHCP lease and default route outbound, make it a VPN client). You could also possibly use the camera to monitor the blinking status LED without doing anything intrusive to the existing electronics.

Liftyee 15 minutes ago||
Intriguing. That circuit board definitely looks like a little company's product from decades ago or a one-off - no silkscreen, single layer, "yellow" board material. Also, in the bottom right, it looks like there are some pads that have been left undrilled. As long as those three mains coloured cables in the bottom left aren't mains, it looks reasonable to keep running (there's not a lot of clearance between that area and the microcontroller...)

Also looks like it was hand assembled, by the component mounting. Wires soldered straight to board isn't great, but not a huge issue if stationary and undisturbed.

grahamburger 6 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.
Melatonic 4 hours ago|||
Heathrow I'm guessing ?
donalhunt 1 hour ago||
In my experience, UK airports seem to not want you to leave the country — contra to the perception the government project regarding not wanting you to stay in the first place. :/

Had a number of experiences where their identity scanners (for some destinations they scan you at the start of security and just before the gate to ensure you get on the right aircraft) failed to be operational resulting in delays that ultimately may have forced me to miss my flight and stay in the UK. On the other hand, arriving from Ireland to the UK results in no checks because of the common travel area — you get waved through a special gate which is reserved for passengers from Ireland. LOL

ndr 6 hours ago||
Is the solution to a positive swab really to keep swabbing until negative?
jkingsman 5 hours ago|||
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".
shmeeed 2 hours ago||
TIL! I appreciate the explanation, never considered them to be that sophisticated.
dmurray 45 seconds ago||
Also, it's not illegal to travel when covered in nitrate dust. Maybe you really were working with explosives or fertilizers earlier in the day. So it really should be just a flag to check that you don't still have the explosives with you.
dekhn 4 hours ago||||
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.

jandrese 2 hours ago||||
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.
grahamburger 6 hours ago||||
Apparently! That or I just have a trustworthy face haha
tristor 5 hours ago|||
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.

jkingsman 5 hours ago|||
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).
shmeeed 2 hours ago||
Those guys must have a lot of fun with vapes. The liquid is 50-70% glycerine, and you get the stuff everywhere.
donalhunt 1 hour ago|||
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.
dwayne_dibley 5 hours ago||
This is what I want the internet to be. Great read.
unkeen 4 hours ago||
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!!
dang 4 hours ago|||
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.

EvanAnderson 2 hours ago|||
> 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.

dang 59 minutes ago||
I've actually never connected the two before! The brain is so context-dependent...
Melatonic 4 hours ago|||
You could almost say like it was TIME something like this hit number 1 !

badoosh

....I'll see myself out

defjm 3 hours ago||
This made me giggle! Thanks.
stronglikedan 39 minutes ago|||
I came here via unslop.news, so I have no idea what you're talking about.
Yhippa 3 hours ago||
This is how it was about 15 years ago.
ad133 2 hours ago||
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.
IsopropylMalbec 5 hours ago||
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.

js2 5 hours ago|
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.

compiler-guy 4 hours ago|||
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.

fusslo 2 hours ago||
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

icantevenhold 3 hours ago|||
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
rmccue 2 hours ago|||
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.
card_zero 2 hours ago|||
YMD is Sweden or Hungary. MDY is US and pre-1960s UK. YDM is Latvia. DYM and MYD are up for grabs.
buildsjets 4 hours ago||
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

PHLAK 4 hours ago||
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.
EvanAnderson 4 hours ago||
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.
buildsjets 4 hours ago||
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...

SaberTail 6 hours ago||
> 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.

MacNCheese23 2 hours ago||
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.

oniony 5 hours ago|||
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.

ErroneousBosh 4 hours ago||
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.

jdnordy 4 hours ago||
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.
crumpled 2 hours ago||
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.
bluGill 3 hours ago|||
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.

AlecSchueler 4 hours ago||
Depends on your local community, worth considering what spaces there are and just reaching out or showing up.
timsneath 5 hours ago|
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!
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