* more realistic fluid motion
* cheaper, easier build
* easier to debug
* risk of wet butt when you sit down
* less joy of doing hard thingsHave you tried to fabricate such a box? I wouldn't be so sure.
- Light: If they make a clanking noise every 5 seconds when you pick them up and put them down its just distracting.
- Plastic: There are other materials that work, but in general metals and fabrics react too strongly with your fingers over time, whereas plastic can be easily cleaned.
Having a little water window isn't a problem, but the water is also not as directly cool looking. Usually in the '90s you'd get those mixed color oil/water toys where the colors would make them stand out more, but shaking them would mix the substances causing them to lose function.
As such the electronic version is quite durable in comparison.
* excessively fast fluid motion at card scaleTo get of fluid to behave that way on the scale of several inches, the fluid would have to be massive (very dense) while simultaneously gravity would have to be reduced.
/joy of doing hard things intensifies
I knew a chap that had a similar hardware business card (I don't remember exactly what it did, but it wasn't as cool as this one).
I remember that his card was pretty scuffed up, and he insisted I give it back, after he handed it to me. Bit weird.
I’d probably even keep it in my desk to play with. After a few weeks I’d accidentally have this guy’s email/linkedin memorized for eternity
What an absolute baller this guy is.
And you know what? About 8 months later my windshield got sprayed by gravel. That guy got the business (he’s a friend of a friend after all, and I had his number in my wallet).
I’d say the issue isn’t that cards are outdated. It’s that people aren’t using them correctly.
But, I don’t think he’d be handing out $20 BOM cards that freely. I was more validating that there is still probably a market of people where $20 cards might make sense. As in the example I posed, a business card isn’t providing any additional information. By the time I meet these people in my office, we’ve already exchanged emails and had some conversations on the phone and are acquainted. That’s what led to the in-person meeting. I know their names and have them in my contacts.
But, just as it felt like a social faux pas to receive a business card at a housewarming party, I think it also feels like a faux pas to meet someone in a business environment (where you are the selling party) and not give out a card during the initial first handshake interaction. This is a pretty low volume and high value moment for that person so a $20 card is no big deal and could easily make sense.
If I consider changing jobs, or if I need those very particular services he's getting a call :-).
They are fairly fancy moo.com cards, with my name, email, and cellphone. Nothing else.
On the back, is a fancy “dragon head” logo (the one you see, if you look at most of my social media accounts). It’s actually my old artist signature. It’s over a burnt umber gradient.
People like them, and use them.
I remember a story linked from here, recently, where a designer submitted a CV that was a custom-made widget of some kind.
He got the job.
Another trick was adding a "Valid until <YEAR> in the cover". It seems counterintuitive that a CV expires, but it made a few companies approach me for an updated CV.
These are generally done as portfolio projects. It’s driving a lot of traffic to the website.
Producing a small number to hand out to potential freelance clients or job prospects is also common.
snicker
Are there services that you can send the BOM and board files too, and not only do you get the PC board back, but it's populated? Will they do that for a onesy-twosy thing like this?
Then all you have to do is supply the battery and download the firmware (however that is done).
There's definitely an entire business available for expensive trade show merchandise, including electronic business cards. People routinely give away shirts and other merchandise that cost far more than $10..
Now whether you get it populated or not..
https://github.com/Nicholas-L-Johnson/flip-card/blob/main/ki...
That is based on the price for low quantity (1-500 pieces) though; if you were to build more than one board you would buy more LEDs, pushing the per-LED price (way) down. You can get 4,000 LEDs for $30.'
Edit: here is the LED in question, from the BOM [1].
Please don’t do this.
But presumably with some knowledge or review of it. Commenting with a link to the first Google result comes across about as well as quoting an LLM output.
their heart might be in the right place tbh. But that's my 2 cents.
Or is it really ChatGPTs 2 cents? Copy-pasting LLM responses is as useful as posting a "let me google that for you" link. It's a lazy response at a minimum.
The anti AI HN comments are the new anti Bitcoin - your replies are much worse than someone sharing the gpt output.
A google link at least allows me to verify sources and use my brain.
It's like having a group conversation in person and one member of the group contributes nothing but things they read off Google.
Should they have searched it and kept the information to themselves? Or should they have done additional research after asking AI(like looking into its sources) and tried confirming it and actually listing us the sources of their discoveries and then disclose that they used AI.
I generally feel like they wanted to share the information but I mean :/ I'd be actually interested as to what you offer him to do actually if he was really curious and did search chatgpt.
I always feel like knowledge should be open and that just saying that knowledge out loud doesn't hurt but I do agree with your point too wholeheartedly so its nuanced imo.
>It sort of reminds me of those research professors that have received multiple awards and their website is an unstyled HTML page with 4 links
>If they used a sans-serif font then they would have nailed it
>this particular serif font was also a poor choice out of the variety of serif fonts out there
>that's awesome, but i think since it's a business card the text on the back should be more legible (nicer font and/or bigger)
Ok, for real though, can someone just tell me what font to use? We can all see this isn't my strong suit and now you're in my head.
— White on black (inverse) is less legible, so all else equal compared with black on white the font should be bolder and/or bigger for equivalent readability. (Using caps or small caps is also OK in display text like titles, if it reads easier.)
— Legibility is also impaired by visual noise around the text (it’s not a single color but there is some pattern, for example). Compensate for that, too.
— Unless you really know what you are doing, stick to one font. You can use bolder/lighter variants of the same font.
— Never compress fonts vertically or horizontally. Instead, pick a different font. Many fonts have condensed/compressed alternatives, or there is also Impact if you want it.
— Use white space. Padding lets it breathe.
— Use typographic features. Em dashes (separate them by thin spaces), bullets.
> Embedded Design⠀⠀⠀Hardware ∙ Firmware
or
> Embedded Design — Hardware, Firmware
vs.
> Embedded Design - Hardware/Firmware
That said, everything except the first two is subjective. A relaxed vibe of “don’t give a damn about it” might be strategic if you are good at what you do (and crucially it is not design), as long as your card is legible and does its function.
https://kicanvas.org/?github=https%3A%2F%2Fgithub.com%2FNich...
@creator of the card (phirks?): have you considered further interactivity or maybe using the LED matrix for showing text or other information?
You could use touch buttons for control as they basically add nothing to the BOM?
Edit: this is of course really awesome as it is
Text has been less of a success. Having the letters be easily legible takes more space than I would have thought, and the small pixel fonts don't look great with the big spacing between the LEDs. Maybe some scrolling text would look good, but I haven't focused on it too much. I tried getting a QR code displayed, but it didn't want to scan.
For buttons, I'm kind of married to the idea of no buttons. The accelerometer does recognize clicks and double clicks in different directions, so that might be useful for something.
I encourage anyone who wants to fork/contribute/post issues on this to do so and I'll try to be a good maintainer.
What’s the update rate of the LED matrix if I may ask? Maybe the combination of an accelerometer and the LEDs lends itself to a persistence of vision display?
I can't imagine you'll be on the job market for long (and I certainly hope not).
This is such an amazing looking for work ad, I'd imagine you'll get snapped right up.
Major kudos on this. It's amazing!
This is awesome. I bet we see a lot of these in the future once people realize it's possible to have a USB-C port on your board with no extra parts and zero soldering.
There was a whole game based on this sort of thing back on the Acorn Archimedes: Cataclysm https://www.youtube.com/watch?v=3Byyz1Vlv8w It got remade for the 360, but the original was regarded at the time as surprisingly impressive for the machines it was running on.
Oxygen Not Included simulates a whole bunch of different kinds of fluids and gasses, and has a sandbox mode and debug tools.
I love using it as a kidpix-like painting tool, just to see how all the different materials interact.
The problem is so much of the effect of a disco ball is irregular directional beams reflecting off it, which would be hard to do.
Which was posted here a while back: https://news.ycombinator.com/item?id=44144750
I'm a sucker for a novel clock concept, and the level of detail he's operating at is beautiful to witness. I actually have a collection of cool clocks here: https://lynkmi.com/oisin/Clocks
£1200 for one though.. oof.
For most of us makers it's very hard to make money as our things sell for so little that it's like 3€ per hour to make them. Kudos to this guy, he really does his marketing right.
Several years ago I ran into this project [0] and got overwhelmed even the algorithm can be written in 88 lines of C++. I realized that out of all CS topics, physical simulation is probably the one I knew the less (not saying I'm a compiler/database expert or something, but at least I've implemented a toy compiler and some basic data structures used in database. When it comes to physical simulation my bran just draws a blank.)
"Physical simulation" is a very broad scope, so your code for simulating fluids is going to be very different from your code for simulating planetary orbits, and at times it may feel a bit ad hoc. But at its foundation physical laws are written in differential equations and linear algebra.
So whatever algorithm lets you numerically integrate several inter-related variables is going to be broadly applicable to simulating any physical phenomena. At the simplest end of the spectrum you just naively approximate integration by brute force. Eg at each step just update your physical state variables by doing velocity += acceleration, position += velocity. This is called Euler's method, and while simple, it accumulates unacceptable errors rather quickly in most circumstance. The more advanced approach is to use a method like Runge Kutta. In circumstances where you have some known property, like say energy conservation, you can implement a method which explicitly imposes the constraint. This is good for cases where the motion is highly periodic as it prevents the numerical error from accumulating exponentially in orbits that spiral out of control.
Of course at some point you'll have to grapple with the issue of if you are simulating trajectories of free particles or values of neighboring grid points in a field. This question of how best to encode physical systems and simulate them cuts to the heart of physics.
I'll leave it at the old cliche "information is physical"
Solar system simulation is another fun one, leaning more into nummerical differental equations solving.
Ex: if player presses jump button, set state to 'jumping' and dy to 1. Every frame, dy = dy * 0.9. When dy <= 0, set state to 'falling'. Every frame, dy = dy * 1.1 until dy = 1 (terminal velocity). Then add some collision detection.
I think those basics are also behind the simpler physics simulations, the 'falling sand' types would be ideal for an application like this.
Eulerian (grid-based) simulation is one of the classic examples.
To see what might peak you interest, the videos in [2] could be a good starting point.
[1]: https://www.coursera.org/learn/statistical-mechanics
[2]: https://matthias-research.github.io/pages/tenMinutePhysics/i...
I'll give you a simple example. For diffusion of heat between 2 points, the rate of change (first derivative) is proportional to the difference in temp between them. So you make an update rule for points on a grid that says "calc the average difference of a cell's temp with that of its neighbors, multiply by some constant, and that is the amount to update this cell at this time. Run that for every cell in parallel, many times." Then you tack on a visualization and you can watch the heat diffuse. A fun example would be the cooling of the proto-Earth. You can watch the crust form.
Heat diffusion is a good starter problem. So is gravitational interaction.
The algorithm is a more expensive combination of two simulation methods to support both splashes and incompressibility, but the benefits are barely visible in the simple container.
https://www.tokyoartsandspace.jp/en/creator/index/B/124.html
You can also hand-assemble surface mount parts by applying solder paste carefully to the pads, then placing all the components on the paste and heating the board until all the solder melts. That would have very time consuming for all those LEDs!
Here is the link to the episode (without a timestamp): https://www.youtube.com/watch?v=S78lYvjo2JQ
And this is how the badges looked/worked: https://www.digikey.com/en/maker/tutorials/2025/assembling-y...
For a few hobby or toy things, the fixed rate board stuffing shops are the way to go.
He did (there are centroid files in the production folder, which tell the board house where to put the components), but you'd be surprised at how possible it is to assemble something like this by hand. You won't believe me, but I find it easier than through-hole soldering (because you don't have to keep flipping the board over).
But there's a 99.9% chance this was done in-house at JLC or PCBWay.
*I haven't looked at the specific parts for this board, the LEDs look nice and could be a little pricey.
e.g.:
a similar one was beamu (eink screen, nrf52 with bt): https://nicgardner.com/2020/05/09/beamu-first-impressions/
(this was an actual product, if a bit pointless. i have one still)
any others?
1. You don't voluntarily give your financial transaction info to big tech.
2. Your card details are hidden. So if your wallet gets stolen, less danger of fraudulent transactions.
3. Carry one heavy card instead of many light ones.
4. Don't have to memorize the pin of all the cards. Or the pin just shows on the mini screen after finger print authentication.
I would think a business card that is as thick as a usbc port + pcb would be considered pretty thick.
so is it ultrathin relative to a phone?
This is a very good example, nice work !
Wack font. Circuits exposed. Pixels with fat borders between them. An ugly charging port. But more stuff, packed into a small sleek volume than reasonably possible. Working perfectly.
That’s not Jobs. Oh, no. It’s effing Woz.
The guy is a true hardware engineer.
https://github.com/Nicholas-L-Johnson/flip-card/blob/main/me...
Flat ones do exist. I have one eink TOTP card that's no thicker than a normal credit card.
And also an airtag style tracker that's about twice as thick. Maybe it uses the same kind of battery.
https://www.lithium-polymer-battery.net/ultra-thin-lithium-p...
Standard credit card: 0.76mm thick
THANK YOU phirks for the correction. Much appreciated.
Like this one:
https://www.adafruit.com/product/5180?srsltid=AfmBOopEIapZEq...
But with supports along the sides that could solder one the top and/or bottom of the PCB. You'd have a notch cut out for the connector.
rather it's even smaller, it simply has the inner part of a usb c connector - exactly the thickness of the pcb
similar to https://github.com/cnlohr/ch32v003_3digit_lcd_usb/
Fluid simulation pendant https://mitxela.com/projects/fluid-pendant
The LiR2032 (rechargable lithium) are slightly higher voltages but pretty much the same total energy.
Fwiw if you ever have electronics that require 3V minimums the LiR2023 is better than the CR2032 since it's 3.7V vs 3V in the same form factor. It's common knowledge that the ESP32 for example can glitch on a CR2023 since it needs 3V minimum but it'll actually run fine on a LiR2032.
I made "PalmJoint", a beamable Palm pleasure card for CodeCon 2002, when everybody was beaming their contacts around by IR at conferences, I would beam an interactive doobie simulator a bunch of people could play together in a circle. Each person gets their own doobie, and you can have contests to see who can virtually smoke theirs the quickest, or keep it lit for the longest time. I never get around to implementing an IR token passing network:
https://donhopkins.com/home/images/PalmJoint.png
https://donhopkins.com/home/PalmJoint/Src/PalmJointMain.cpp
Some conferences of the era had kiosks with IR LEDs that beamed out a Palm app with a conference map and schedule, which would have been great to hijack for beaming out PalmJoints instead.
My first thought with this card was that it could be "gamified" into something that kids would probably love. A clique-y, social thing where kids could "pour" some of their fluid into another's card, with NFC or something. User preference colors that don't change when "poured" could help indicate how many different people have interacted with your card.
But enough spitballing. There's no killer idea there. Just something I'll be amused to see show up as a value-add for some other kind of toy, or whatever.
Remember those little LCD cube block toys with the stick dudes that lived in 'em, then when you plug 'em together they interact? Those were the days.
Maybe I grew out of the age range or maybe the whole market of silly knick-knacks has died out but they definitely drove my interest in all things electronic.
44 points by mekaj on Nov 20, 2015 | hide | past | favorite | 11 comments
https://news.ycombinator.com/item?id=10600001
The T2 Tile Project:
https://www.youtube.com/channel/UC1M91QuLZfCzHjBMEKvIc-A
Artificial Life Creation T-0 and Launching - T2sday Update 3135:
Then you can lay the fertilized eggs at any GPS coordinate to gestate and hatch later on.
That could start a whole genre of AI (Artificial Insemination) Life Simulation games.
The Bluetooth Bong was a vast improvement over the MIDI Bong.
MIDI aftertouch on the carburetor was a nice improvement over your grandfather's old Serial Acoustic 300 Baud ASCII Bong, but the Bluetooth Bong HID has a much higher bandwidth, multitouch chording, accelerometer tilt tracking, modular monophonic splash resistant microphone, and they weren't as easy to accidentally knock over because they were wireless. An extremely important feature if you have cats around.
But nothing beats a high-end spill-proof Rooᴙ 802.11be NVB (Network Video Bong) with fully submersible IPX8 smoke resistant stereo mics.
Also it's a bit startling to see floating-point code used so freely. Shows how rapidly the capabilities of MCUs have developed. 15 years ago, doing floating point on a microcontroller would be unspeakable /s
After many years of self-hosting an email server I also came to the realization that it's not worth the hassle (in terms of maintenance / problems) and I switched to Proton Mail.
Using a custom domain with Proton Mail is not free (and all the other alternatives I know of are the same) and there's little advantage other than having a nice name. I think for a HW Engineer this is good enough.
We're talking about someone handing out $17/ea business cards here.
