There’s A Wrinkle In This 3D Printed Wankel

February 10, 2022 by Matthew Carlson 10 Comments

Rotary engines such as the Wankel have strange shapes that can be difficult to machine (as evidenced by the specialized production machines and patents in the 70s), which means it lends itself well to be 3D printed. The downside is that the tolerances, like most engines, are pretty tight, and it is difficult for a printer to match them. Not to be dissuaded, [3DprintedLife] designed and built a 3D printed liquid piston rotary engine. The liquid piston engine is not a Wankel and is more akin to an inside-out Wankel. The seals are on the housing, not the rotor itself, and there are three “chambers” instead of two.

The first of many iterations didn’t run. There was too much friction, but there were some positive signs as pressure was trapped in a chamber and released as it turned. The iterations continued, impressively not using any o-rings to seal, but instead sanding each part down using a 1-2-3 block as a flat reference, within 25 microns of the design. Despite his care and attention to detail, it still couldn’t self-sustain. He theorizes that it could be due to the resin being softer than other materials he has used in the past. Not to be left empty-handed, he built a dynamo to test his new engine out. It was a load cell and an encoder to measure speed and force. His encoder had trouble keeping up, so he ordered some optical limit switches.

This engine is a follow-on to an earlier 3D printed air-powered Wankel rotary engine, and we’re looking forward to part two of the liquid piston series. Video after the break.

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Sergiy Nesterenko giving his Remoticon 2021 talk

Remoticon 2021 // Sergiy Nesterenko Keeps Hardware Running Through Lightning And Cosmic Rays

February 10, 2022 by Robin Kearey 1 Comment

Getting to space is hard enough. You have to go up a few hundred miles, then go sideways really fast to enter orbit. But getting something into space is one thing: keeping a delicate instrument working as it travels there is quite another. In his talk at Remoticon 2021, [Sergiy Nesterenko], former Radiation Effects Engineer at SpaceX, walks us through all the things that can destroy your sensitive electronics on the way up.

The trouble already starts way before liftoff. Due to an accident of geography, several launch sites are located in areas prone to severe thunderstorms: not the ideal location to put a 300-foot long metal tube upright and leave it standing for a day. Other hazards near the launch pad include wayward wildlife and salty spray from the ocean.

Those dangers are gone once you’re in space, but then suddenly heat becomes a problem: if your spacecraft is sitting in full sunlight, it will quickly heat up to 135 °C, while the parts in the shade cool off to -150 °C. A simple solution is to spin your craft along its axis to ensure an even heat load on all sides, similar to the way you rotate sausages on your barbecue.

But one of the most challenging problems facing electronics in space is radiation. [Sergiy] explains in detail the various types of radiation that a spacecraft might encounter: charged particles in the Van Allen belts, cosmic rays once you get away from Low Earth orbit, and a variety of ionized junk ejected from the Sun every now and then. The easiest way to reduce the radiation load on your electronics is simply to stay near Earth and take cover within its magnetic field.

For interplanetary spacecraft there’s no escaping the onslaught, and the only to survive is to make your electronics “rad-hard”. Shielding is generally not an option because of weight constraints, so engineers make use of components that have been tested in radiation chambers to ensure they will not suddenly short-circuit. Adding redundant circuits as well as self-monitoring features like watchdog timers also helps to make flight computers more robust.

[Sergiy]’s talk is full of interesting anecdotes that will delight the inner astronaut in all of us. Ever imagined a bat trying to hitch a ride on a Space Shuttle? As it turns out, one aspiring space bat did just that. And while designing space-qualified electronics is not something most of us do every day, [Sergiy]’s experiences provide plenty of tips for more down-to-earth problems. After all, salt and moisture will eat away cables on your bicycle just as they do on a moon rocket.

Be sure to also check out the links embedded in the talk’s slides for lots of great background information.

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CX-6000 Pen Plotter Upgrade

February 10, 2022 by Chris Lott 9 Comments

[Terje Io] decided to breathe new life into an old pen plotter — the CX6000 from C. Itoh, a Japanese company that made several printers for Apple in the 1980s. He keeps most of the framework, but the electronics get a major overhaul. The old motors are replaced, the controller and motor drivers are modernized using a Raspberry Pi Pico and stepper motor drivers. After tending to other auxiliary electronics like the control panel and limit switches, it’s time to deal with the firmware.

Rather than reinvent the wheel, [Terje] sensibly built upon existing projects and refactored them for his application. G-Code processing is done by grblHAL, with an added mode to handle HPGL code. He modified the firmware from Motöri the Plotter project to parse HPGL, making his new CX6000+ bilingual.

We covered Motöri way back in 2009, and more recently we wrote about the Teensy Controller using grblHAL, one of the 32-bit big brothers of GRBL. Have you ever restored one of these old plotters? Or is it easier to just build your own these days?

Keebin’ With Kristina: The One With The Ballpoint Typewriters

February 10, 2022 by Kristina Panos 7 Comments

So you want to minimize finger movement when you type, but don’t have three grand to drop on an old DataHand, or enough time to build the open-source lalboard? Check out these two concept keebs from [SouthPawEngineer], which only look like chord boards.

Every key on the home row is a five-way switch — like a D-pad with straight down input. [SouthPawEngineer] has them set up so that each one covers a QWERTY column. So like, for the left pinky switch, up is Q, right is A, down is Z, and left is 1. Technically, the split has 58 keys, and the uni has 56.

Both of these keebs use KB2040 boards, which are Adafruit’s answer to the keyboard-building craze of these roaring 2020s. These little boards are of course easy to program with CircuitPython, which supports KMK, an offshoot of the popular QMK. Thanks for the tip, [foamyguy]!

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Ask Hackaday: What’s Going On With Mazdas In Seattle?

February 10, 2022 by Al Williams 56 Comments

What hacker doesn’t love a puzzle? We have a doozy for you. According to KUOW — the NPR affiliate in Seattle — they have been getting an unusual complaint. Apparently, if you drive a Mazda made in 2016 and you tune to KUOW, your radio gets stuck on their frequency, 94.9 MHz, and you can’t change it.

According to a post from the radio station, it doesn’t just affect the FM radio. A listener named Smith reported:

“I tried rebooting it because I’ve done that in the past and nothing happened,” Smith said, “I realized I could hear NPR, but I can’t change the station, can’t use the navigation, can’t use the Bluetooth.”

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A Simple 3D Printed Rover Design

February 10, 2022 by Lewin Day 4 Comments

There are plenty of RC cars and robot platforms out there that you can buy. However, there’s an understanding that’s gained from building your own rover from the ground up. Which is precisely what [Alex] got from developing this compact 3D printed rover design.

The design is by no means fast; it’s intended more for crawling around “at a slow deliberate pace” as [Alex] puts it. Off-the-shelf 12 V gear motors are used to provide plenty of torque to get around. The modular design means that it can be built with just wheels, or set up with tracks fitted for additional performance in softer terrain. Skid steering is used to turn the platform.

Fitted with a Raspberry Pi Zero 2W, the rover can be controlled remotely over WiFi. A separate FPV camera and transmitter is then used to stream video remotely to pilot the bot. However, if you’re so inclined, you can probably use the Raspberry Pi to stream the video, too.

It’s a fun build and a great way to learn about building rovers and robots that move. We’ve seen some other interesting tracked rovers before, too. Video after the break.

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Breakbeats Courtesy Of The RP2040

February 9, 2022 by Lewin Day 6 Comments

While one often listens to songs or albums in full, sometimes you just want to lay down a simple beat. [todbot]’s latest project promises to do just that.

The build relies on a Raspberry Pi Pico or any other RP2040-based microcontroller board, and is programmed in CircuitPython. The PWM feature is used for audio output, and it’s loaded with different WAV samples of the classic “Amen” break.

Each measure, a random new sample is chosen and played, changing the beat. Even better, all the samples can loop, and they come in varying lengths, allowing them to overlap and lay over each other to add further depth to the mix. It’s a cinch to setup, as CircuitPython has an AudioMixer object built in.

Those wishing to tinker for themselves can find all the code and samples on Github. A build like this one is a great way to start learning about working with audio and music, after all. We’ve seen [todbot]’s work here before, too. Video after the break.

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