[HN Gopher] How a car cigarette lighter works, in CT scans
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How a car cigarette lighter works, in CT scans
Author : jonbruner
Score : 26 points
Date : 2024-07-26 17:25 UTC (5 hours ago)
(HTM) web link (www.lumafield.com)
(TXT) w3m dump (www.lumafield.com)
| Arainach wrote:
| It's a cool explanation, but I'm not sure what a CT scan offers
| that cutting it in half with a bandsaw wouldn't.
| kube-system wrote:
| When all you are is a hammer manufacturer, all your demos look
| like nails.
| mrguyorama wrote:
| In which case the question gets inverted:
|
| Why of all common things you could CT scan and show people,
| you choose something that is kinda obvious to anyone who has
| thought about it for five seconds? I don't think average
| people struggle to understand the concept of "electricity
| makes wire hot", especially if they lived at the same time as
| normal car cigarette lighter usage.
| kube-system wrote:
| Lumafield posts _tons_ of these. I don 't think the average
| person has thought at all about how these work, and even if
| they do, the appeal of these is to look at the pretty
| pictures (and demonstrate the analysis that is possible
| non-destructively to their target audience), not to
| understand "electricity makes wire hot".
|
| They have a scan of a dang football, and it isn't because
| people don't know there's air inside:
| https://www.lumafield.com/article/ct-big-game-football
| ssl-3 wrote:
| Those who have thought about it for more than five seconds
| understand that there is more going on inside of a normal
| car cigarette lighter than "electricity makes wires hot."
| beaglesss wrote:
| IR heat profile might have been cool.
|
| It's a shame cars don't come with them anymore. A lighter can
| save someone's life and cost next to nothing. You can toss a
| lighter in but something about the designated electric plug is
| pleasing and invites you not to lose it.
| peterleiser wrote:
| Yes, very handy even for non-smokers. We have a 2015 vehicle
| that we bought used that came with a cigarette lighter. I
| removed it and put it in the glove box.
| Terr_ wrote:
| It's a scanner company showing off their scanners, they don't
| sell bandsaws. :p
|
| That said, it's a kind of marketing I like, since it does have
| some underlying product-performance and educational virtue to
| it.
| floatrock wrote:
| Same reason every coding tutorial -- no matter the capabilities
| of the language -- starts with a simple "hello world".
|
| Learn with a simple toy example before moving onto the
| industrial-grade deconstruction that really shows the power of
| the tool. These guys have done CT scans of things like real vs.
| fake airPods and charger bricks to show what really justifies
| their (probably) 7 or 8-figure price tags.
|
| This one is just content marketing of something anyone can wrap
| their head around.
| kube-system wrote:
| Seeing clever, simple, and reliable mechanisms like this make me
| think that digital electronics has really enabled modern
| engineers to be lazy.
| gwbas1c wrote:
| > this design, developed in the 1950s, is entirely analog
|
| Uhm, how is this analog? Perhaps "electro-mechanical?" Is there
| such a thing as a "digital cigarette lighter?"
|
| It's not like the electric circuit is an analog of the act of
| lighting a cigarette; as opposed to what we commonly use the word
| "analog" to mean that something in the system is an analog to
| what's being recorded or processed. (IE, in analog tape the
| magnetic signal is an analog to the real signal, or in analog TV
| the signal is an analog to the brightness of the picture at a
| specific moment in time.)
| moolcool wrote:
| It's a valid distinction of the author to make. I don't know if
| there's such thing as a cigarette lighter which uses digital
| circuitry, but there theoretically could be.
|
| The way the lighter in the article works is both analog _and_
| electro-mechanical.
| throwup238 wrote:
| _> Is there such a thing as a "digital cigarette lighter?"_
|
| Yes: https://www.walmart.com/ip/Flameless-Cigarette-Lighter-
| USB-R... :-)
| ofalkaed wrote:
| It is an analog of a traditional burning fuel lighter. But they
| are using analog to refer to the fact it relies completely on
| analog circuitry and I suspect they actually wanted to point
| out the fact that it is 100% passive circuitry relying solely
| on the electrical and physical properties of a resistor (the
| coil) which is the interesting thing here, the resistor is its
| own temperature sensor. They sort of explain this and walk you
| through it all, probably trying to stick to language suited to
| their audience.
| gwbas1c wrote:
| > it relies completely on analog circuitry
|
| A resistor is not "analog circuitry"
|
| > the resistor is its own temperature sensor
|
| No, the clasp that holds the spring down is a bi-metallic
| strip that bends when it reaches a temperature. This is not
| "analog" because there is nothing for it to represent.
|
| The article is merely a case of calling something old
| "analog" without knowing what the word means.
| ofalkaed wrote:
| A resistor is not circuitry, the resistor is a part of a
| circuit which in this case is analog.
| big-green-man wrote:
| Computation on the bare metal of the universe, no abstraction or
| emulation required. I love it.
| wumms wrote:
| > You might think such a system would involve a thermostat, a
| microcontroller, and an actuator, but this design [...] has
| bimetallic arms with steel on the outer surface and copper on the
| inner surface. As the filament heats up, the arms warm up,
| causing the copper to expand faster than the steel. This
| expansion pushes the arms open, releasing the lighter. The coil
| spring then causes the handle to pop out, signaling that the
| lighter is ready.
|
| Maybe I am in a picky mood, but for me the intro made it sound
| like all three items (thermostat, microcontroller, actuator)
| would not be necessary, though of course only the microprocessor
| is missing from the design (thermostat -> bimetallic arms,
| actuator -> spring).
|
| Mandatory link to another marvel in the same problem space (I
| found the 19min video worth the time):
|
| "An Antique Toaster That's Better Than Today's [video]"
|
| https://www.youtube.com/watch?v=1OfxlSG6q5Y
|
| https://news.ycombinator.com/item?id=21164014 [2019, 386 points|5
| years ago|232 comments]
| 1970-01-01 wrote:
| No, you have the correct take. The bimetallic bond is a
| thermostat. The spring is an actuator.
| andrepd wrote:
| Heh, I correctly guessed the channel just by reading the title
| :)
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