[HN Gopher] Self-Soldering Circuits [video]
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Self-Soldering Circuits [video]
Author : zdw
Score : 202 points
Date : 2023-01-21 04:22 UTC (18 hours ago)
(HTM) web link (www.youtube.com)
(TXT) w3m dump (www.youtube.com)
| sen wrote:
| People are missing the point here. Carls entire channel is filled
| with really cool experiments in making PCBs do things people
| wouldn't normally think of. There doesn't have to be a practical
| purpose really, he just loves experimenting.
|
| I really love his flexible PCB experiments too, he's made a lot
| of awesome things from them.
| joshu wrote:
| exactly this. The creativity process is hampered by forcing
| every single possibility along the path to a new invention to
| something that is completely practical and useful.
|
| On top of that he's probably figured out a bunch of interesting
| things that he can apply to his next project and other things
| and so on. this is good stuff.
| sandworm101 wrote:
| Except i can think of many uses for this.
|
| A self-heating board is more efficient than heating an entire
| enclosure. A sensitive circuit or part could use this trick to
| efficiently keep key componants warm on demand without an
| entire external heating system. And dont let Louis Rossmann
| about this. Inbuilt desoldering circuits underneath key
| componants might make at-home board repair too easy even for
| his tastes.
| franky47 wrote:
| We had this use-case back when I worked for a pro-audio
| company building analog synthesizers.
|
| One of the components of a voltage controlled oscillator
| (VCO) is a linear to exponential converter, that converts the
| 1V per octave control voltage to a per-hertz reset pulse for
| the sawtooth waveform.
|
| Such components can be done in various ways, but one of the
| most traditional is to use the exponential part of a
| transistor's voltage-to-current transfer function (not sure
| what the actual term is here). The issue is that this
| function is very sensitive to temperature, and so fluctuation
| in temperature on this part can easily detune the VCO by a
| very audible amount. Fluctuation is less of an issue at
| higher temperatures (around 70-80degC), so the solution was:
| heat!
|
| The trick we implemented in the synth was to use a transistor
| array in a chip: use two transistors for the Lin/Exp
| converter, another as a heat source (we nicknamed it "the
| oven"), and another as a heat measurement device, to get some
| sort of PID feedback loop. I believe there were five
| transistors in the chip, so there was a leftover that got
| used for another purpose.
|
| Surprisingly efficient, though we could still hear some pitch
| drop when blowing on the transistor array chip. Once in the
| enclosure, we figured only applying some ice on the front
| panel would have an effect.
|
| This "heating trace" in the PCB would have been a good
| alternative, as some of those transistors arrays were
| particularly hard to source (we needed a particular
| transistor type, can't remember which).
| markrages wrote:
| Oven-stabilized crystal oscillators are a time-honored
| technique for precision electronics.
|
| It turns out that no matter how carefully you stabilize a
| circuit for temperature changes, it gets much more stable
| when held at a controlled temperature.
|
| Arrangements for this go from simple (gluing the component
| to a PTC thermistor driven at constant voltage) to
| elaborate (thermocouple-controlled PID heater in multiple
| styrofoam insulating enclosures). There are some pictures
| at https://en.wikipedia.org/wiki/Crystal_oven
|
| I've never seen PCB traces used for this, but I've always
| wanted to try making a clock from a piece of LCD color-
| change material laminated to a PCB with traces in seven-
| segment patterns.
| franky47 wrote:
| Interesting application, wouldn't you get high remanence
| on the segments turning off, waiting for the heat to
| dissipate?
|
| Could make for a nice transition effect though.
| amelius wrote:
| Heating is usually not the problem with electronics ...
| sandworm101 wrote:
| Maybe in the lower 48. Up north, all sorts of circuits get
| exposed to surprisingly low temperatures, resulting in all
| sorts of gremlins.
| goodpoint wrote:
| You can heat up only the key components using resistors.
| sandworm101 wrote:
| You can install toaster coils too. A pcb heater layer
| directly under a temperature-sensitive chip is much more
| direct, and thinner. I see a cold-weather cellphone with a
| touchscreen that can get up to workong temperature quickly.
| paulkrush wrote:
| My head went straight to designing boards that can solder
| themselves to other boards autonomously.
| stockhorn wrote:
| This reminds me of Solder Cubes:
| https://m.youtube.com/watch?v=BUMnESXLWkM
| ablatt89 wrote:
| Reminds me of the Star Trek episode about nanites self-
| replicating.
| unhammer wrote:
| Inspired by https://twitter.com/twowordhorror
| bityard wrote:
| I have made self-unsoldering circuits before, do those count?
| vocram wrote:
| Only if it was a feature.
| a9h74j wrote:
| To demonstrate a mechanical analogy for impedance, something-
| something use electrolytics in place of diodes.
| taffronaut wrote:
| Only if the components actually remove themselves from the
| board. Bonus points if they make it to somewhere else in the
| room. Consider it like a faulty component quitting before it
| gets fired. I once had a bus transceiver that unsoldered itself
| from a card on an extender and ended up on the floor.
| AussieWog93 wrote:
| You could probably launch a little SMD resistor quite far by
| deliberately popping an electrolytic cap...
| jrockway wrote:
| YouTube has been recommending this channel to me for a while. It
| was a long journey to get there, with a lot of prototype
| hotplates made out of PCBs along the way. Worth watching if
| you're bored some night.
| gaze wrote:
| It's a cute trick but I can't imagine a worse ground plane.
| People say ok -- this is fine for low frequency circuits. There
| is no such thing as a low frequency circuit when there's a
| microcontroller present since the clock edges have frequency
| content well into the GHz. The only way I could imagine getting
| away with this is if you sacrifice a layer to the heater and put
| a ground plane between it and the rest of the PCB stack as a
| shield. Still I think it would be better to scatter resistors
| around the board and heat sink them to a solid ground plane. I
| don't know. I love basically everything Carl does but if anyone
| is considering this seriously they need to learn a bit about
| Maxwell's equations.
| franky47 wrote:
| An interesting spin on the Mission: Impossible assignment
| devices.
|
| "This device will self-desolder in 5 seconds"
| lightedman wrote:
| This is actually one of the designs we use at work for building
| connector-only PCBs (like what you'd find in track lighting
| raceways) because our FR4 board used for that application is so
| thin that it can't go into the reflow oven, it will flex and slip
| off the rails when it heats up. We just make one big PCB with an
| array of connector-only parts and a track heater built-in, run
| the board through the solder stencil, pull it out, place the
| connectors by hand, slap the board on a lapped-flat granite block
| with a heater under it, hook up power, and watch it until it
| reflows. We use an extremely-low temp bismuth solder that reflows
| just a bit above water's boiling point for these boards.
|
| Nice to see hobbyists in the field coming up with the same
| concepts.
| key_stroker wrote:
| I like the way he's screen printing the soldering paste.
| voxadam wrote:
| The "screen" he's using in the video is called a stencil.
| They're made out out of thin stainless steel. These days
| they're pretty easy to come by, even for the hobbyist.[0]
|
| [0] https://www.oshstencils.com/ (one of many hobbyist level
| examples)
| guerrilla wrote:
| Yes! I'd never seen that before in the hobbyist sphere and
| suddenly I don't hate SMDs.
| ilyt wrote:
| Most board vendors can sell you the stencil for your PCB for
| very cheap
| iamflimflam1 wrote:
| Yes, I thought this was pretty common now. I do it every
| time as it hardly adds any cost.
|
| It's also worth looking at the costs for SMT assembly.
| Companies like JLC are amazingly cheap for fully assembled
| boards (provided you stick to their standard parts
| catalog).
| ilyt wrote:
| I was almost going to do that for one of my projects, I
| got my design right on time for chip crisis to start....
|
| But yeah, even for something like 10 boards the prices
| for assembly has become pretty reasonable, especially if
| you design for the parts they have in stock.
| makapuf wrote:
| I consider soldering the board a bit too far on the
| externalize my hobby side. I like soldering those !
| unwind wrote:
| That was fantastic. As far as I can tell it's an original idea
| which in this area is rather cool by itself.
|
| I guess I'm curious how much worse the heater-shorted-into-
| grounding-plane performs as compared to a classic full grounding
| plane.
|
| If anyone is curious about the cool-looking pcb holder used in
| the early shots, that's the Omnifixo [1]. It's been on my wanted
| list for a while but it's not cheap and often sold out (I think
| it's basically a one-man company).
|
| [1]: https://omnifixo.com/
| fest wrote:
| Thanks for mentioning Omnifixo- when you said it's not cheap, I
| mentally prepared myself for a price tag of several hundred
| EUR. I find the ~60EUR price very reasonable (IIRC a single
| stickvise with PTFE jaws is around the same price point).
| mikewarot wrote:
| This could be done with a normal ground plane by extending it out
| both sides of a board. A microwave transformer with the high
| voltage secondary cut out to make a 2 turn transformer could
| supply more than enough current... use a thermocouple the same
| way, and a Triac to control the primary, and Bob's your Uncle.
|
| Doing a row of vias on both sides then paralleling the top/bottom
| traces to make some big T shaped terminals might make it easier
| to get uniform current distribution.
| TheSpiceIsLife wrote:
| https://youtu.be/LMT1sn1bKRY
| Renaud wrote:
| It's a great hack and a cool demo that may have (very) limited
| real-life niche applications, but it's not really worth it unless
| you only make a couple of PCB per year and can't afford a small
| oven.
|
| Where this is great is that you can finely control the
| temperature of the board since you're in control of the current
| you pump into it.
|
| Where it's not great is that it uses a full layer and could cause
| issues if any of your PCB needs special considerations, when
| using high frequency clocks or RF (say implementing a switch mode
| power supply can be quite sensitive to how your layers are
| composed). You also end-up with either a floating layer or a
| ground layer that has a long path instead of a real ground plane.
| That could also create noise issues.
|
| If you assemble a few PCB a year, a PCB oven is fairly cheap. You
| can make one with a regular US$50 oven and a PID control kit or
| just buy a dedicated one like the T-962 (that can be further
| hacked and improved) for about US$250 from Aliexpress.
|
| But that hack is still cool and Carl Bugeja's channel[1] has lots
| of fun projects that push PCB to new limits for hobbyists,
| showing what you can achieve with flex PCB in particular and
| using them as mechanical interfaces for creating motors,
| actuators, etc. It's a great channel!
|
| [1]: https://www.youtube.com/@CarlBugeja
| fest wrote:
| Perhaps the particular T962a was just a bad product, but at
| $WORK we just could not get it working reliably across many
| types of PCBs- it really required tuning the profile to each
| type of PCB (small, large, black solder mask vs green, etc)-
| and yes, a colleague spent a day or two installing the cold
| junction compensation mod. From what I saw- there was just too
| large variance in IR emissivity/absorption of the PCBA and
| their thermal properties, which resulted in scorched connectors
| on one batch and raw/non-molten paste on another batch- with
| exactly the same profile.
|
| I achieved much better results with just a (convection) toaster
| oven and multimeter thermocouple- I only added PID controller
| because I started using the oven for drying something as well.
| IshKebab wrote:
| > Can't afford a small oven.
|
| You don't even need that; you can solder PCBs in a frying pan.
| It works very well. I never even tried an oven to be honest
| because a frying pan worked so well and Adafruit or someone
| like that said it was better than a toaster oven.
|
| Although I do have induction hobs now. Not sure if a PCB would
| be too happy about that. But if not you can buy a portable mini
| hob for like PS15.
|
| It's a really cool tech demo though.
| 4b11b4 wrote:
| I once bought a George Foreman grill and put sand in it.
| amelius wrote:
| Put the frying pan only works for single-sided PCBs ;)
| IshKebab wrote:
| That is true, but I think most hobby PCBs are single sided.
| makapuf wrote:
| Not necessarily single copper sided, but they tend to be
| single side for components.
| IshKebab wrote:
| That's called single _layer_ and roughly nobody is doing
| single layer boards.
| lightedman wrote:
| Single layer is absolutely used en-masse.
|
| Track lighting circuitry is one example. LED lighting is
| another.
| namibj wrote:
| Clothes iron.
| Animats wrote:
| > dedicated (reflow oven) like the T-962
|
| The trouble with the T-962 is that the stock units heat so
| unevenly that you can scorch the center of the board while
| getting cold solder joints near the edges.
|
| I have one of those with the mods for improved firmware and
| better thermocouple references. It's OK. The firmware runs the
| fan all the time, even during heating, which improves the heat
| distribution. There's a better mod which adds a second fan.
|
| A number of companies in China made clones of those things, but
| none of them seem to have done a redesign to make a better one
| at roughly the same price. Now there seems to be a new
| generation of these things, with more fan power. That's a step
| forward. No idea if they're any good. (There are reflow oven
| review sites, as bogus as mattress review sites.) There ought
| to be a good $200 reflow oven by now.
|
| You can buy good small reflow ovens from the US and Germany,
| but prices are upwards of US$3000.
| fest wrote:
| There are relatively affordable vapor phase ovens- at $WORK I
| arranged the purchase of Vapor Phase One- it works really
| well. However, some people are more sensitive to the
| resulting smell.
| amelius wrote:
| Sensitive as in a allergic reaction or a headache? Or just
| a dislike of the smell?
| fest wrote:
| From what I gathered- just dislike, mixed with some
| concerns. I didn't smell anything apart from the usual
| flux smell, but I have very little sense of smell.
| lightedman wrote:
| My issue with vapor-phase is that it tends to cause a lot
| of tombstoned or sleeping components. It's pretty good for
| multi-leg components like power ICs and processors and BGA
| components, but not so good on two-conductor resistors,
| capacitors, jumpers, etc. This is mostly because with
| vapor-phase you can't really control the thermal profile of
| the reflow.
| fest wrote:
| My understanding is that Galden vapor is dense, so you
| get a layer of hot vapor near the fluid, with lower
| temperature further from fluid (where there is less
| vapor)- the required thermal profile is maintained by
| controlling position of the boards..
| amelius wrote:
| This misses the entire purpose of a ground plane. The point of a
| ground plane is that return currents can follow roughly the same
| path as the forward going currents at higher frequencies, so the
| inductive loop the combined path forms is as small as possible.
| Also, a real ground plane can provide shielding by allowing
| currents that oppose electromagnetic fields, but these currents
| have to go in loops also.
| fr0sty wrote:
| It isn't really clear in the video, but that is a 4 layer board
| and there is another ground plane layer elsewhere. The heater
| loop doesn't connect to any components.
| stavros wrote:
| Why is he connecting it to ground then?
| ilyt wrote:
| To what else then ? Leaving it unconnected would be worse,
| leaving it at ground level makes it at worst act like small
| capacitance to ground for nearby stuff
| femto wrote:
| He's built an "antenna plane".
| nixpulvis wrote:
| Yea, perhaps you could be clever with that as well later
| on...? Probably not the most precise design, but it seems
| honestly a lot less hassle than heating an oven.
| SynAck6 wrote:
| I have been following this Youtuber for a while now, and I have
| been amazed by his creativity and unorthodox use of flexible
| PCBs. Strongly recommend watching a few more of his videos
| Roark66 wrote:
| It's an entertaining hack. I think it should be considered in
| this context.
|
| If we start thinking about it in practical terms it stops making
| any sense. Specifically, a standard 2 layer board costs few $ to
| make. Here we're paying a huge premium for extra internal layers.
| You may as well take that money and put it towards a hob with an
| scr and a cheap controller to solder them on it.
| alexvoda wrote:
| That actually depends on the specific costs. There is a clear
| business desire to replace capex with opex even when the
| resulting expenditure is higher. This achieves that at the pcb
| soldering level.
|
| It does not have to be a good idea to get traction.
| paulkrush wrote:
| This is cool! One more notch in the theory of getting a true
| RepRap to reproduce...
| nixpulvis wrote:
| Excuse me, but did he just make a cheeseless pizza!? I guess
| baked tomato sauce will bind toppings a little bit, but you'll
| lose all the texture of the sauce this way :(
| Waterluvian wrote:
| He probably finds that with cheese he loses all the texture and
| binding in the bowel movements.
| SAI_Peregrinus wrote:
| Historical pizza is basically just any round bread with some
| sort of topping(s). Max Miller's Tasting History showed a 16'th
| century pizza recipe from the Vatican with powdered sugar and
| rose water for toppings[1].
|
| [1] https://www.youtube.com/watch?v=h6XvMKdD2tY
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(page generated 2023-01-21 23:02 UTC)