A lot of making goes on in this community these days, but sometimes you’ve just gotta do some old fashioned hacking. You might have grabbed an old Speak and Spell that you want to repurpose as an interface for a horrifyingly rude chatbot, or you’ve got a calculator that is going to become the passcode keypad for launching your DIY missiles. You want to work with the original hardware, but you need to figure out how to interface all the buttons yourself.
Thankfully, this is usually an easy job. The vast majority of buttons and keypads and keyboards are all implemented pretty much the same way. Once you know the basics of how to work with them, hooking them up is easy. It’s time to learn about key matrixes!
A hackerspace is a place that generally needs to be accessed by a wide group of people, often at weird and unusual hours. Handing around keys and making sure everything is properly locked up can be messy, too. To make it easy for hackers to get in to [Peter]’s local hackerspace, a simple electronic system was whipped up to grant access.
The combined use of QR code & PIN adds a layer of security.
The basic components of the system are a keypad, a QR code and barcode scanner, a stepper motor, an Arduino Nano, and a Raspberry Pi. The keypad is read by an Arduino Nano, which is also responsible for talking to a stepper motor driver to actuate the lock cylinder. A secondary Arduino mounted inside the building is used to control the stepper motor, which actuates the lock cylinder once authentication is complete.
The system works on the basis of two-factor authentication. Regular users authenticate to enter by presenting a QR code or barcode, and entering a matching PIN number. The system can also be set up for PIN-only entry on a temporary basis.
For example, if the hackerspace is running an event, a simple four-digit pin can allow relatively free access for the duration without compromising long-term security. Actual authentication is handled by the Raspberry Pi, which takes in the scanned barcode and/or PIN, hashes it, and checks it against a backend database which determines if the credentials are valid for entry. If so,they command the second Arduino to unlock the door.
While it’s not technically necessary for a project like this — in fact, you could argue it’s preposterously overkill — we have to take particular note of the machined aluminum enclosure for the keypad. Mere mortals could just run it off on their 3D printers, but if you’ve got access to a CNC router and a suitably chunky piece of aluminum, why not show off a bit?
Naturally, Regenerator 2000 is built with full support for the 6502 instruction set, including undocumented op-codes as well. It’s able to automatically create labels and comments and can be paired with the VICE C64 emulator for live debugging. You can do all the usual debug stuff like inspecting registers, stepping through code, and setting breakpoints and watchpoints when you’re trying to figure out how something works. It can even show you sprites, bitmaps, and character sets right in the main window.
Historically, moving and pointing a camera while filming was the job of a highly-skilled individual. However, there are machines that can do that, enabling all kinds of fancy movement that is difficult or impossible for a human to recreate. A great example is this pan-tilt build from [immofoto3d.]
The build uses a hefty cradle to mount DSLR-size cameras or similar. It’s controlled in the tilt axis by a chunky NEMA 17 stepper motor hooked up to a belt drive for smooth, accurate movement. Similarly, another stepper motor handles the pan axis, with an option for upgrade if you have a heavier camera rig that needs more torque to spin easily. Named Gantry Bot, it’s an open-source design with source files available, so you can make any necessary tweaks on your own. You will have to bring your own control mechanism, though—telling the stepper motors what to do and how fast to do it is up to you.
It’s a heavy-duty build, this one, and you’ll really want a decent metal-capable CNC to get it done, along with a 3D printer for all the plastic pieces. With that said, we’ve featured some other similar builds that might be more accessible if you don’t have a hardcore machine shop in the basement. If you’ve got your own impressive motion rig in the works, be sure to notify the tipsline!
Many different types of printers have entered the market over the years. Most of us are intimately familiar with the common inkjet and laser, both of which can be found in homes and offices all over the world. Then there are those old dot matrix printers that were so noisy in use, thermal printers, and even solid ink printers that occupied a weird niche for a time.
However, very little attention is ever paid to the LED printer. They’re not actually that uncommon, and they work in a very familiar way. It’s just that because these printers are so similar to an existing technology, they largely escaped any real notability in the marketplace. Let’s explore the inner workings of the printer tech that the world forgot.
Okay, 68 pins does look like a lot when you arrange them like that.
The concept is simple enough. [Nagy] merely intended to wire the 286 up to a Raspberry Pi Pico that could emulate other parts of a computer that it would normally expect to talk to. This isn’t so hard with an ancient CPU like the 286, which has just 68 pins compared to the 1000+ pins on modern CPUs. All it took was a PLCC-68 socket, an adapter PCB, a breadboard, and some MCP23s17 logic expanders to give the diminutive microcontroller enough I/O. With a bit of work, [Nagy] was able to get the Pi Pico running the 286, allowing it to execute a simple program that retrieves numbers from “memory” and writes them back in turn.
Notably, this setup won’t run the 286 at its full clock speed of 12 MHz, and it’s a long way off from doing anything complex like talking to peripherals or booting an OS. Still, it’s neat to see the old metal live again, even if it’s just rattling through a few simple machine instructions that don’t mean a whole lot. [Nagy] equates this project to The Matrix; you might also think of it as a brain in a jar. The 286 is not in a real computer; it’s just hooked up to a microcontroller stimulating its various pins in a way that is indistinguishable from its own perspective. Continue reading “Making A 286 Think It’s Alive Again”→
One of the problems with being a graffiti artist is that you have to carry around a different spray can for each color you intend to use. [Sandesh Manik] decided to solve this problem by building a rig that can produce a wider range of colors by mixing the paint from several cans at once. Check it out in the video below.
The project is called Spectrum. It uses four off-the-shelf spray paint cans—colored red, blue, yellow, and white—and mixes them to create a wider range of colors. All four cans are hooked up to a single output nozzle via a nest of tubing and a four-to-one tube manifold. Key to controlling the flow of paint is a custom device which [Sandesh] calls the “rotary pinch valve,” with one fitted to the feed line coming from each spray can. These valves use a motor-driven lever to pinch a plastic tube shut, allowing them to control the paint flow. This design keeps the mechanism and paint completely separate, which was important to stop paint from fouling the valves in short order. It also prevents backflow, which keeps the paint going towards the outlet and prevents ugly messes. By quickly actuating the valve, the paint flow from each can is modulated to mix various colors as desired.
