The Altair Shield

From PDPs to Connection Machines, the Hackaday crowd are big fans of blinkenlights. While this project isn’t an old CPU, RAM, ROM, and an S-100 bus wrapped up in a fancy enclosure, it is a great recreation of the Altair 8800, the historic kit computer that supposedly launched the microcomputer revolution.

[Justin] says his project is just another Altair 8800 clone, but this one is cut down to the size of an Arduino shield. This is in stark contrast to other Altair recreations, whether they are modern PCs stuffed in an old case, modern replicas, or a board that has the same functionality using chunky toggle switches.

On board [Justin]’s pocket-sized Altair are a few LEDs, some DIP switches, and an octet of spring-loaded dual throw switches that wouldn’t look out of place in a 40-year old computer.

This shield targets the Arduino Due rather than the Mega, but only because the Due performs better running an Altair simulation. Everything is there, and a serial terminal is available ready to run BASIC or any other ancient OS.

Soluble Molds For Composite Parts

People have been experimenting with 3D printed molds for fiberglass and carbon fiber for a while now, but these molds really aren’t much different from what you could produce with a normal CNC mill. 3D printing opens up a few more options for what you can build including parts that could never be made on any type of mill. The guys at E3D are experimenting with their new dissolvable filament to create incredible parts in carbon fiber.

For the last year, E3D has been playing around with their new soluble filament, Scaffold. This is the water-soluble support material we’ve all been waiting for: just throw it in a bucket of warm water and it disappears. The normal use case for this filament is as a support material, but for these experiments in composites, E3D are just printing whole objects, covering them in carbon fiber prepreg, vacuum bagging them, and allowing them to cure. Once the carbon fiber isn’t floppy and gooey, the support material is dissolved in water, leaving a perfect composite part.

E3D aren’t that experienced with composites, so they handed a bit of filament off to So3D for some additional experimentation. The most impressive part (in the title pic for this post) is a hollow twisted vase object. This would have required a six-part machined mold and would have cost thousands of dollars to fabricate. Additional experiments of embedding ABS parts inside the Scaffold mold were extremely successful.

As you would expect, there are limitations to this process. Since E3D are using a dissolvable mold, this is a one-time deal; you’re not going to be pulling multiple composite parts off a 3D printed mold like you would with a machined mold. Curing the parts in a very hot oven doesn’t work — Scaffold filament starts to sag around 60°C. Using prepreg is recommended over dry fabric and resin, but that seems to be due more to the skill of the person doing the layup rather than an issue with materials.

Hackaday Links: March 12, 2017

The world’s first public installation of a solar roadway caught fire or something.

Hey hardware nerds in the UK! Nottingham is having its first monthly hardware meetup. This get together is being put together by [Spencer], creator of the extremely popular RC2014 Homebrew Z80 computer kit. The meetup is free, and it’s happening this Tuesday.

[danjovic] sent in a link to this YouTube channel of a guy building stuff out of PVC sheets and CA glue. There’s a lot of stuff in here from a PVC tripod to instructions on how to get PVC sheets out of PVC pipe. Small warning: this is PVC, and it will kill you instantly, for reasons we can’t yet determine. Additionally, he’s heating PVC, which means cancer for your yet-unborn great-grandchildren. How it both kills you while still allowing you to breed is beyond our comprehension. That’s how bad PVC really is.

NASA has updated their available software catalog. If you want to go to Saturn, you first have to go to Venus three times. Here’s a tool that packs batteries. You should build a router for the interplanetary Internet.

[jlbrian7] is Breaking Android over on

Last week, we had a Raspberry Pi Hack Chat with [Roger Thornton], the principal hardware engineer at Raspberry Pi. We talked about the hardware that goes into the Raspberry Pi (and the new Pi Zero W), and gave away a few Pi Zero Ws to a few people on that had great ideas for a project. One of the winners of a free Raspberry Pi Zero W was [arsenijs] for his Raspberry Pi Project. This is a really great project that uses a Raspberry Pi and Raspberry Pi accessories. It’s pushing the envelope of what a Pi can be, and a free Raspberry Pi Zero W couldn’t have gone to a more worthy project.

What are you doing the weekend of March 31st? We’re going to New Jersey for the Vintage Computer Festival East. This is one of the better cons we go to. Maybe this year we’ll organize a trip to the pinball museum in Asbury Park.

Raspberry Pi-Based Game Boy Emulator

The most popular use for a Raspberry Pi, by far, is video game emulation. We see this in many, many forms from 3D printed Raspberry Pi cases resembling the original Nintendo Entertainment System to 3D printed Raspberry Pi cases resembling Super Nintendos. There’s a lot of variety out there for Raspberry Pi emulation, but [moosepr] is taking it to the next level. He’s building the smallest Pi emulation build we’ve ever seen.

This build is based on the Pi Zero and a 2.2″ (0.56 dm) ili9341 TFT display. This display has a resolution of 240×320 pixels, which is close enough to the resolution of the systems the Pi Zero can emulate. The Pi Zero and display are attached to a beautiful purple breakout board (shared on OSH Park) along with a few 5-way nav switches, a charger for a Lipo battery, and a few other bits and bobs.

Right now, [moosepr] is experimenting with adding sound to his board. It’s easy enough to get sound out of a Pi Zero — it’s just PWM coming from a few pins — but audio also needs an amp, a speaker, and more space on the board. To solve this problem, [moose] found a few piezo transducers from musical greeting cards. These are designed to be thin and as loud as possible, and attaching these directly to the PWM pins providing audio might just work. This is a project to keep an eye on, if only to see if cheap piezos work for low-fi audio in retro emulators.

Putting Pi In Infrared Doohickies

The Raspberry Pi Zero W is a tiny, cheap Linux computer with WiFi. It’s perfect for Internet of Things things such as controlling ceiling fans, window blinds, LED strips, and judgmental toasters. This leads to an obvious question: how do you attach your ceiling fan and LED strips to a Pi Zero? A lot of these things already have infrared remotes, so why not build an infrared hat for the Pi? That’s what [Leon] did, and it’s Open Hardware with documentation.

[Leon]’s Anavi Infrared Pi Hat does exactly what you think it should do. There’s an IR receiver, two IR LEDs, and UART pins for debugging. That’s all you need to control infrared doohickies over the Internet, and [Leon] wrapped it up in a nice neat package that’s the same size as a Raspberry Pi Zero. Add on some documentation and you have something we rarely see: a project meant to be used by other people.

This focus on allowing people to actually use what [Leon] created can lead to only one cynical conclusion: he’s probably selling these things somewhere. The cynic is never surprised. [Leon] has a crowdfunding campaign going, that’s over 400% funded with a month to go. That’s okay, though: all the design files are available so if you want to build your own without supporting people who build useful devices, have at it.

Two Weeks Until The Greatest 3D Printer Meetup On The Planet

Every year, sometime in March, the world’s preeminent 3D printing enthusiasts gather in the middle of nowhere This is MRRF, the Midwest RepRap Festival. It’s only two weeks away. You need to come. Get your (free) tickets here. I’ll be there, and Hackaday is proud to once again sponsor the festival.

I need to backtrack a bit to explain why MRRF is so great. I go to a lot of cons. Maker Faire is getting old, CES was a horror show. Even DEF CON is losing its charm, and all of these cons have the same problem: there are too many people. MRRF does not have this problem. For one weekend a year, everyone who is anyone in the 3D printing world makes it out to the middle of Indiana. This is a small meetup, but that’s what makes it great. It’s a bunch of dorks dorking around for an entire weekend.

If that’s not enough to convince you, take a look at the previous coverage Hackaday has done from MRRF. The PartDaddy, an 18-foot-tall 3D printer will be there. The world’s largest 3D printed trash can will not. Prusa is coming in from Prague, E3D is coming in from England. Judging from past years, this is where the latest advancements in home 3D printing first appear. This is not an event to miss.

You might be wondering why the world’s greatest 3D printer festival is in the middle of nowhere. Goshen, Indiana is the home of SeeMeCNC, builders of the fantastic Rostock Max 3D delta bot. MRRF is hosted by the SeeMeCNC guys. If you’re exceptionally lucky, you’ll get to go over to the shop and see a demo of their milling machine that cools parts by ablation.

We Can Now 3D Print Slinkys

A mark of a good 3D print — and a good 3D printer — is interlayer adhesion. If the layers of a 3D print are too far apart, you get a weak print that doesn’t look good. This print has no interlayer adhesion. It’s a 3D printed Slinky, the kind that rolls down stairs, alone or in pairs, and makes a slinkity sound. Conventional wisdom says you can’t print a Slinky, but that didn’t stop [mpclauser] from trying and succeeding.

This Slinky model was made using a few lines of JavaScript that output a Gcode file. There is no .STL file, and you can’t edit this CNC Slinky in any CAD tools. This is also exceptionally weird Gcode. According to [mpclauser], the printer, ‘zigzags’ between an inner and outer radius while constantly increasing the height. This is the toolpath you would expect from a 3D printed Slinky, but it also means the usual Gcode viewers throw a fit when trying to figure out how to display this thing.

All the code to generate your own 3D printable Slinky Gcode file is up on [mpclauser]’s Google Drive. The only way to see this print in action is to download the Gcode file and print it out. Get to it.