An HP9863C partially disassembled on a workbench

Repairing A $25,000 HP Workstation To Run Pac-Man

The microcomputer revolution of the 1970s and 1980s turned computers from expensive machines aimed at professionals into consumer products found in the average household. But there always remained a market for professional users, who bought equipment that was so far ahead of consumer gear it seemed to belong in a different decade. While a home computer enthusiast in 1981 might fork out a few hundred dollars for an 8-bit machine with 64 KB of memory, a professional could already buy a 32-bit workstation with 2.8 megabytes of RAM for the price of a brand-new sports car. [Tech Tangents] got his hands on one of those machines, an HP Series 200 9863C from 1981, and managed to get it up and running.

The machine came in more-or-less working condition. The display cable turned out to be dodgy, but since it was just a straight-through sub-D cable it was easily replaced. Similarly, the two 5.25″ floppy drives were standard Tandon TM100-2As which [Tech Tangents] had some experience in repairing, although these specific units merely needed a thorough cleaning to remove forty years’ worth of dust. Continue reading “Repairing A $25,000 HP Workstation To Run Pac-Man

Blood Pressure Monitor For Under $1

Medical equipment is not generally known for being inexpensive, with various imaging systems usually weighing in at over a million dollars, and even relatively simpler pieces of technology like digital thermometers, stethoscopes, and pulse oximeters coming in somewhere around $50. As the general pace of technological improvement continues on we expect marginal decreases in costs, but every now and then a revolutionary piece of technology will drop the cost of something like a blood pressure monitor by over an order of magnitude.

Typically a blood pressure monitor involves a cuff that pressurizes against a patient’s arm, and measures the physical pressure of the blood as the heart forces blood through the area restricted by the cuff. But there are some ways to measure blood pressure by proxy, instead of directly. This device, a small piece of plastic with a cost of less than a dollar, attaches to a smartphone near the camera sensor and flashlight. By pressing a finger onto the device, the smartphone uses the flashlight and the camera in tandem to measure subtle changes in the skin, which can be processed in an app to approximate blood pressure.

The developers of this technology note that it’s not a one-to-one substitute for a traditional blood pressure monitor, but it is extremely helpful for those who might not be able to afford a normal monitor and who might otherwise go undiagnosed for high blood pressure. Almost half of adults in the US alone have issues relating to blood pressure, so just getting information at all is the hurdle this device is attempting to overcome. And, we’ll count it as a win any time medical technology becomes more accessible, more inexpensive, or more open-source.

Modular Keyboard And Custom Game Controller

Most video games, whether on console or PC, have standardized around either a keyboard and mouse or an analog controller of some sort, with very little differences between various offerings from the likes of Sony, Microsoft, Nintendo, or even Valve. This will get most of us through almost all video games, but for those looking to take their gameplay up a notch or who are playing much more complex games, certain specialized controllers are available, but they might not meet everyone’s specific needs. Thanks to this custom, modular keyboard anyone should be able to make exactly the controller they need.

The device features a grid of 15 interfaces where modules like buttons, potentiometers, encoders, and joysticks can be placed. Each module can be customized to a significant extent on their own, and they can be placed anywhere on the grid. The modules themselves can be assigned to trigger keyboard presses or gamepad motions depending on the needs of the user. A Raspberry Pi handles the inputs and translates them to the computer, so in that regard it functions no differently than a standard keyboard or gamepad would. Programming is done by sending commands via a USB serial port, with the ability to save various configurations as well.

The modular controller is open-source in terms of hardware and software, with easy assembly using through-hole components and a customizable 3D printed cover for anyone looking to make their own. The project’s creator [Daniel] had flight simulators in mind when designing the device, which often benefit from having more specialized controllers, but any game with lots of specific inputs from Starcraft to League of Legends could benefit from a custom controller or keyboard like this. Flight simulators are more often the targets of specialized and unique controls, though, like this custom yoke or this physical control panel.

A Volumetric Display With A Star Wars Look And Feel

It may not exactly be what [Princess Leia] used to beg [Obi-Wan] for help, but this Star Wars-inspired volumetric display is still a pretty cool hack, and with plenty of extra points for style.

In some ways, [Maker Mac]’s design is a bit like a 3D printer for images, in that it displays slices of a solid model onto closely spaced planar surfaces. Sounds simple enough, but there are a lot of clever details in this build. The main component is a lightly modified LCD projector, a DLP-based machine with an RGB color wheel. By removing the color wheel from the projector’s optical path and hooking its sync sensor up to the control electronics, [Mac] is able to increase the framerate of the display, at the cost of color, of course. Other optical elements include a mirror to direct the projected images upwards, and a shutter harvested from an old pair of 3D TV glasses. Continue reading “A Volumetric Display With A Star Wars Look And Feel”

Hackaday Prize 2023: Sleek Macro Pad Makes 2FA A Little Easier

We all know the drill when it comes to online security — something you know, and something you have. But when the “something you have” is a two-factor token in a keyfob at the bottom of a backpack, or an app on your phone that’s buried several swipes and taps deep, inconvenience can stand in the way of adding that second level of security. Thankfully, this “2FA Sidecar” is the perfect way to lower the barrier to using two-factor authentication.

That’s especially true for a heavy 2FA user like [Matt Perkins], who typically needs to log in and out of multiple 2FA-protected networks during his workday. His Sidecar is similar in design to many of the macro pads we’ve seen, with a row of Cherry MX key switches, a tiny TFT display — part of an ESP32-S3 Reverse TFT Feather — and a USB HID interface. Pressing one of the five keys on the pad generates a new time-based one-time password (TOTP) and sends it over USB as typed keyboard characters; the TOTP is also displayed on the TFT if you prefer to type it in yourself.

As for security, [Matt] took pains to keep things as tight as possible. The ESP32 only connects to network services to keep the time synced up for proper TOTP generation, and to serve up a simple web configuration page so that you can type in the TOTP salts and service name to associate with each key. He also discusses the possibility of protecting the ESP32’s flash memory by burning the e-fuses, as well as the pros and cons of that maneuver. The video below shows the finished project in action.

This is definitely a “use at your own risk” proposition, but we tend to think that in the right physical environment, anything that makes 2FA more convenient is probably a security win. If you need to brush up on the risks and benefits of 2FA, you should probably start here.

Continue reading “Hackaday Prize 2023: Sleek Macro Pad Makes 2FA A Little Easier”

Jack In, The 2023 Cyberdeck Challenge Starts Now

The modern laptop is truly a masterpiece of engineering, craming an incredible amount of processing power into a thin and lightweight package that can run for hours on its internal batteries, all for just a few hundred bucks. Combine that with the ubiquitous smartphone, and it’s safe to say that the state of mobile computing has never been better.

A retro-futuristic portable computer with a touch screen and a shoulder strapDespite this, over the last several years we’ve watched cyberdecks go from a few one-off examples to a vibrant community of truly personal computing devices. While there are some exceptions, most of them are larger, more expensive, and less portable than what’s available on the commercial market. But that’s not the point — a cyberdeck should be a reflection of the hacker that built it, not the product of a faceless megacorp.

Which is why we’re excited to officially announce the 2023 Cyberdeck Challenge, starting now and running all summer through to August 15th.

Whether it’s a ridiculously over the top wearable that wouldn’t look out of place in a cyberpunk anime or a pocket-sized gadget that you operate with a handful of unlabeled buttons, we want to see it. All we ask is that it be a functional device capable of some useful amount of computing, anything beyond that is up to you. Turn in one of the top three designs, and you’ll earn a $150 USD DigiKey shopping spree, just what you need to pack a few extra bells and whistles into your rig.

Continue reading “Jack In, The 2023 Cyberdeck Challenge Starts Now”

Punched Cards Are In The Cloud, With This Arduino

Grizzled veterans of the computing industry will relate stories of submitting projects on stacks of punched cards, something those of us who stored their 8-bit works on audio cassettes could only imagine. But for those who fancy experimenting with the format it’s still possible to make a basic card reader using LEDs and light sensors, as [Nino Ivanov] has done using an Arduino Uno as the brains. And these aren’t just for show, each of his cards holds a LISP program that runs in a cloud service.

The Uno does the job of reading, passing its data over its USB serial port to a tablet. On the tablet the serial data is piped to a cloud API to a LISP interpreter. It seems a needlessly complex way to run a factorial program and it’s certainly a little over the top, but on the other hand we love it as a glorious combination of the old and the new. With only 23 characters per card it’s quite an impressive feat to even fit a program on the format, perhaps writing code to fit on minimalist punched cards like this could become a programming challenge in its own right for a generation accustomed to mega-and gigabytes.

If you fancy a go yourself, this isn’t the first punched card reader we’ve shown you.

Continue reading “Punched Cards Are In The Cloud, With This Arduino”