Back To The Future, 40 Years Old, Looks Like The Past

July 3, 2025 by 61 Comments

Great Scott! If my calculations are correct, when this baby hits 88 miles per hour, you’re gonna see some serious shit. — Doc Brown

On this day, forty years ago, July 3rd, 1985 the movie Back to the Future was released. While not as fundamental as Hackers or realistic as Sneakers, this movie worked its way into our pantheon. We thought it would be appropriate to commemorate this element of hacker culture on this day, its forty year anniversary.

If you just never got around to watching it, or if it has been a few decades since you did, then you might not recall that the movie is set in two periods. It opens in 1985 and then goes back to 1955. Most of the movie is set in 1955 with Marty trying to get back to 1985 — “back to the future”. The movie celebrates the advanced technology and fashions of 1985 and is all about how silly the technology and fashions of 1955 are as compared with the advancements of 1985. But now it’s the far future, the year 2025, and we thought we might take a look at some of the technology that was enchanting in 1985 but that turned out to be obsolete in “the future”, forty years on. Continue reading “Back To The Future, 40 Years Old, Looks Like The Past” →

It’s 2025, And We Still Need IPv4! What Happens When We Lose It?

July 3, 2025 by 71 Comments

Some time last year, a weird thing happened in the hackerspace where this is being written. The Internet was up, and was blisteringly fast as always, but only a few websites worked. What was up? Fortunately with more than one high-end networking specialist on hand it was quickly established that we had a problem with our gateway’s handling of IPv4 addresses, and normal service was restored. But what happens if you’re not a hackerspace with access to the dodgy piece of infrastructure and you’re left with only IPv6? [James McMurray] had this happen, and has written up how he fixed it.

His answer came in using a Wireguard tunnel to his VPS, and NAT mapping the IPv4 space into a section of IPv6 space. The write-up goes into extensive detail on the process should you need to follow his example, but for us there’s perhaps more interest in why here in 2025, the loss of IPv4 is still something that comes with the loss of half the Internet. As of this writing, that even includes Hackaday itself. If we had the magic means to talk to ourselves from a couple of decades ago our younger selves would probably be shocked by this.

Perhaps the answer lies in the inescapable conclusion that IPv6 answers an address space problem of concern to many in technical spaces, it neither solves anything of concern to most internet users, nor is worth the switch for so much infrastructure when mitigations such as NAT make the IPv4 address space problem less of a problem. Will we ever entirely lose IP4? We’d appreciate your views in the comments. For readers anxious for more it’s something we looked at last year.

Reliving VHS Memories With NFC And ESPHome

July 3, 2025 by 10 Comments

Like many of us of a certain vintage, [Dillan Stock] at The Stock Pot is nostalgic for VHS tapes. It’s not so much the fuzzy picture or the tracking issues we miss, but the physical experience the physical medium brought to movie night. To recreate that magic, [Dillan] made a Modern VHS with NFC and ESPHome.

NFC tags are contained in handsomely designed 3D printed cartridges. You can tell [Dillan] put quite a bit of thought into the industrial design of these: there’s something delightfully Atari-like about them, but they have the correct aspect ratio to hold a miniaturized movie poster as a label. They’re designed to print in two pieces (no plastic wasted on supports) and snap together without glue. The printed reader is equally well thought out, with print-in-place springs for that all important analog clunk.

Electronically, the reader is almost as simple as the cartridge: it holds the NFC reader board and an ESP32. This is very similar to NFC-based audio players we’ve featured before, but it differs in the programming. Here, the ESP32 does nothing related directly to playing media: it is simply programmed to forward the NFC tag id to ESPHome. Based on that tag ID, ESPHome can turn on the TV, cue the appropriate media from a Plex server (or elsewhere), or do… well, literally anything. It’s ESPHome; if you wanted to make this and have a cartridge to start your coffee maker, you could.

If this tickles your nostalgia bone, [Dillan] has links to all the code, 3D files and even the label templates on his site. If you’re not sold yet, check out the video below and you might just change your mind. We’ve seen hacks from The Stock Pot before, everything from a rebuilt lamp to an elegant downspout and a universal remote.

Continue reading “Reliving VHS Memories With NFC And ESPHome” →

Smallest Gaming Mouse Has Crazy Fast Polling Rate And Resolution

July 2, 2025 by 11 Comments

[juskim] wanted to build a tiny mouse, but it couldn’t just be any mouse. It had to be a high-tech gaming mouse that could compete with the best on raw performance. The results are impressive, even if the final build is perhaps less than ideal for pro-level gameplay.

The build riffs on an earlier build from [juskim] that used little more than a PCB and a 3D-printed housing to make a barebones skeleton mouse. However, this one ups the sophistication level. At the heart of the build is the nRF54L15 microcontroller, which is paired with a PAW3395 mouse sensor which is commonly used in high-end gaming mice. It offers resolution up to 26K DPI for accurate tracking, speeds up to 650 ips, and 8 kHz sampling rates. Long story short, if you want fine twitch control, this is the sensor you’re looking for. The sensor and microcontroller are laced together on a custom PCB with a couple of buttons, a battery, and a charging circuit, and installed in a barebones 3D-printed housing to make the final build as small as possible.

The only real thing letting the design down is the mouse’s key feature—the size. There’s very little body to grab on to and it’s hard to imagine being able to play most fast-paced games at a high level with such a tiny device. Nevertheless, the specs are hardcore and capable, even if the enclosure isn’t.

[juskim] loves building tiny peripherals; we’ve featured his fine work before, too. Video after the break.

Continue reading “Smallest Gaming Mouse Has Crazy Fast Polling Rate And Resolution” →

Reservoir Sampling, Or How To Sample Sets Of Unknown Size

July 2, 2025 by 2 Comments

Selecting a random sample from a set is simple. But what about selecting a fair random sample from a set of unknown or indeterminate size? That’s where reservoir sampling comes in, and [Sam Rose] has a beautifully-illustrated, interactive guide to how reservoir sampling works. As far as methods go, it’s as elegant as it is simple, and particularly suited to fairly sampling dynamic datasets like sipping from a firehose of log events.

While reservoir sampling is simple in principle it’s not entirely intuitive to everyone. That’s what makes [Sam]’s interactive essay so helpful; he first articulates the problem before presenting the solution in a way that makes it almost self-evident.

[Sam] uses an imaginary deck of cards to illustrate the problem. If one is being dealt cards one at a time from a deck of unknown size (there could be ten cards, or a million), how can one choose a single card in a way that gives each an equal chance of having been selected? Without collecting them all first?

In a nutshell, the solution is to make a decision every time a new card arrives: hold onto the current card, or replace it with the new one. Each new card is given a 1/n chance of becoming held, where n is the number of cards we’ve seen so far. That’s all it takes. No matter when the dealer stops dealing, each card that has been seen will have had an equal chance of ending up the one selected.

There are a few variations which [Sam] also covers, and practical ways of applying it to log collection, so check it out for yourself.

If [Sam]’s knack for illustrating concepts in an interactive way is your jam, we have one more to point out. Our own Al Williams wrote a piece on Turing machines; the original “universal machine” being a theoretical device with a read/write head and infinite paper tape. A wonderful companion to that article is [Sam]’s piece illustrating exactly how such a Turing machines would work in an interactive way.

The door-unlocking mechanism, featuring a 3D printed bevel gear and NEMA 17 stepper.

Hack Swaps Keys For Gang Signs, Everyone Gets In

July 2, 2025 by 11 Comments

How many times do you have to forget your keys before you start hacking on the problem? For [Binh], the answer was 5 in the last month, and his hack was to make a gesture-based door unlocker. Which leads to the amusing image of [Binh] in a hallway throwing gang signs until he is let in.

The system itself is fairly simple in its execution: the existing deadbolt is actuated by a NEMA 17 stepper turning a 3D printed bevel gear. It runs 50 steps to lock or unlock, apparently, then the motor turns off, so it’s power-efficient and won’t burn down [Binh]’s room.

The software is equally simple; mediapipe is an ML library that can already do finger detection and be accessed via Python. Apparently gesture recognition is fairly unreliable, so [Binh] just has it counting the number of fingers flashed right now. In this case, it’s running on a Rasberry Pi 5 with a webcam for image input. The Pi connects via USB serial to an ESP32 that is connected to the stepper driver. [Binh] had another project ready to be taken apart that had the ESP32/stepper combo ready to go so this was the quickest option. As was mounting everything with double-sided tape, but that also plays into a design constraint: it’s not [Binh]’s door.

[Binh] is staying in a Hacker Hotel, and as you might imagine, there’s been more penetration testing on this than you might get elsewhere. It turns out it’s relatively straightforward to brute force (as you might expect, given it is only counting fingers), so [Binh] is planning on implementing some kind of 2FA. Perhaps a secret knock? Of course he could use his phone, but what’s the fun in that?

Whatever the second factor is, hopefully it’s something that cannot be forgotten in the room. If this project tickles your fancy, it’s open source on GitHub, and you can check it out in action and the build process in the video embedded below.

After offering thanks to [Binh] for the tip, the remaining words of this article will be spent requesting that you, the brilliant and learned hackaday audience, provide us with additional tips.

Continue reading “Hack Swaps Keys For Gang Signs, Everyone Gets In” →

Subpixel Rendering For Impossibly Small Terminal Text

July 2, 2025 by 45 Comments

When it comes to text, how small is too small? The experts say a six point font is the minimum for readability, but as [James Bowman] shows us, you can get away with half of that. 

The goal is to produce a 40-character display on a 24 mm x 24 mm LCD that has a resolution of 240 x 240 to show a serial terminal (or other data) on the “TermDriver2” USB-to-Serial adapter. With 24 lines, that’s a line per millimeter: very small text. Three points, to be precise, half what the experts say you need. Diving this up into 40 columns gives a character cell of six by nine pixels. Is it enough?

Continue reading “Subpixel Rendering For Impossibly Small Terminal Text” →