Raspberry Pi

1886 Articles

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.

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Super8 Camera Brought To The Modern World

June 30, 2025 by 18 Comments

Certain styles of photography or videography immediately evoke an era. Black-and-white movies of flappers in bob cuts put us right in the roaring 20s, while a soft-focused, pastel heavy image with men in suits with narrow ties immediately ties us to the 60s. Similarly, a film shot at home with a Super 8 camera, with its coarse grain, punchy colors, and low resolution brings up immediate nostalgia from the 80s. These cameras are not at all uncommon in the modern era, but the cartridges themselves are definitely a bottleneck. [Nico Rahardian Tangara] retrofitted one with some modern technology that still preserves that 80s look.

The camera he’s using here is a Canon 514XL-S that was purchased for only $5, which is a very common price point for these obsolete machines, especially since this one wasn’t working. He removed all of the internal components except for a few necessary for the camera to work as if it still was using film, like the trigger mechanism to allow the camera to record. In the place of tape he’s installed a Raspberry Pi Zero 2W and a Camera Module 3, so this camera can record in high definition while retaining those qualities that make it look as if it’s filmed on an analog medium four decades ago.

[Nico] reports that the camera does faithfully recreate this early era of home video, and we’d agree as well. He’s been using it to document his own family in the present day, but the results he’s getting immediately recall Super 8 home movies from the 80s and early 90s. Raspberry Pis are almost purpose-built for the task of bringing older camera technology into the modern era, and they’re not just limited to video cameras either. This project put one into an SLR camera from a similar era.

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Sand Drawing Table Inspired By Sisyphus

June 30, 2025 by 7 Comments

In Greek mythology, Sisyphus was a figure who was doomed to roll a boulder for eternity as a punishment from the gods. Inspired by this, [Aidan], [Jorge], and [Henry] decided to build a sand-drawing table that endlessly traces out beautiful patterns (or at least, for as long as power is applied). You can watch it go in the video below.

The project was undertaken as part of the trio’s work for the ECE4760 class at Cornell. A Raspberry Pi Pico runs the show, using TMC2209 drivers to command a pair of NEMA17 stepper motors to drag a magnet around beneath the sand. The build is based around a polar coordinate system, with one stepper motor rotating an arm under the table, and another panning the magnet back and forth along its length. This setup is well-suited to the round sand pit on top of the table, made with a laser-cut wooden ring affixed to a thick base plate.

The trio does a great job explaining the hardware and software decisions made, as well as showing off how everything works in great detail. If you desire to build a sand table of your own, you would do well to start here. Or, you could explore some of the many other sand table projects we’ve featured over the years.

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Can Digital Poison Corrupt The Algorithm?

June 27, 2025 by 24 Comments

These days, so much of what we see online is delivered by social media algorithms. The operations of these algorithms are opaque to us; commentators forever speculate as to whether they just show us what they think we want to see, or whether they try to guide our thinking and habits in a given direction. The Digital Poison device  from [Lucretia], [Auxence] and [Ramon] aims to twist and bend the algorithm to other ends.

The concept is simple enough. The device consists of a Raspberry Pi 5 operating on a Wi-Fi network. The Pi is set up with scripts to endlessly play one or more select YouTube videos on a loop. The videos aren’t to be watched by anyone; the device merely streams them to rack up play counts and send data to YouTube’s recommendation algorithm. The idea is that as the device plays certain videos, it will skew what YouTube recommends to users sharing the same WiFi network based on perceived viewer behavior.

To achieve subtle influence, the device is built inside an unobtrusive container. The idea being that it could be quietly connected to a given WiFi network to stream endlessly, in turn subtly influencing the view habits of other users on the same network.

It’s difficult to say how well this concept would work in practice. In many cases, sites like YouTube have robust user tracking that feeds into recommendation algorithms. Activity from a random user signed into the same network might not have much of an influence. However, conceptually, it’s quite interesting, and the developers have investigated ways to log the devices operation and compare it to recommendations fed to users on the network. Privacy provisions make this difficult, but it may be possible to pursue further research in this area. Files are on Github for the curious.

Ultimately, algorithms will always be a controversial thing as long as the public can’t see how they work or what they do. If you’re working on any projects of your own in this space, don’t hesitate to let us know!

[Thanks to Asher for the tip!]

Animal Crossing keyboard banner

Making GameCube Keyboard Controller Work With Animal Crossing

June 26, 2025 by 2 Comments

[Hunter Irving] is a talented hacker with a wicked sense of humor, and he has written in to let us know about his latest project which is to make a GameCube keyboard controller work with Animal Crossing.

This project began simply enough but got very complicated in short order. Initially the goal was to get the GameCube keyboard controller integrated with the game Animal Crossing. The GameCube keyboard controller is a genuine part manufactured and sold by Nintendo but the game Animal Crossing isn’t compatible with this controller. Rather, Animal Crossing has an on-screen keyboard which players can use with a standard controller. [Hunter] found this frustrating to use so he created an adapter which would intercept the keyboard controller protocol and replace it with equivalent “keypresses” from an emulated standard controller.

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Photo of Inky Frame e-paper display

Converting An E-Paper Photo Frame Into Weather Map

June 21, 2025 by 6 Comments

Here’s a great hack sent in to us from [Simon]. He uses an e-paper photo frame as a weather map!

By now you are probably aware of e-paper technology, which is very low power tech for displaying images. E-paper only uses energy when it changes its display, it doesn’t draw power to maintain a picture it has already rendered. The particular e-paper used in this example is fairly large (as e-paper goes) and supports color (not just black and white) which is why it’s expensive. For about US$100 you can get a 5.7″ 7-color EPD display with 600 x 448 pixels.

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Build a $35 400 MHz Logic Analyzer

Build A 400 MHz Logic Analyzer For $35

June 12, 2025 by 15 Comments

What do you do when you’re a starving student and you need a 400 MHz logic analyzer for your digital circuit investigations? As [nanofix] shows in a recent video, you find one that’s available as an open hardware project and build it yourself.

The project, aptly named LogicAnalyzer was developed by [Dr. Gusman] a few years back, and has actually graced these pages in the past. In the video below, [nanofix] concentrates on the mechanics of actually putting the board together with a focus on soldering. The back of the build is the Raspberry Pi Pico 2 and the TXU0104 level shifters.

If you’d like to follow along at home, all the build instructions and design files are  available on GitHub. For your convenience the Gerber files have been shared at PCBWay

Of course we have heaps of material here at Hackaday covering logic analyzers. If you’re interested in budget options check out $13 Scope And Logic Analyzer Hits 18 Msps or how to build one using a ZX Spectrum! If you’re just getting started with logic analyzers (or if you’re not sure why you should) check out Logic Analyzers: Tapping Into Raspberry Pi Secrets.

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