Linux Fu: A Little Bit Of (Network) History Repeating Itself

April 26, 2021 by 5 Comments

These days, embedded systems often have networks and that can make them significantly more complex. Networks are usually pretty nondeterministic and there are a variety of oddball conditions. For example, when your public-access pick and place machine gets written up on Hackaday and you suddenly get a 50X surge in traffic, how does your network stack handle it? While there’s no silver bullet for network testing, there are some tricks that can make it easier and one of those is the tcpreplay utilities that allow you to record complex network traffic and then play it back in a variety of ways. This has many benefits, especially if you manage to capture that one thing that triggers bad behavior sporadically. Being able to play it back on demand can speed up diagnostics considerably.

General Idea

You probably know that tcpdump allows you to grab packet captures from a network interface and save them to a file. If you prefer a GUI, you probably use Wireshark, which uses the same underlying library (libpcap) to grab the data. In fact, you can capture data using tcpdump and look at it with Wireshark, although there are other tools like tcptrace or Ngrep that can work with the output, also.

While the output of the command can be a little cryptic without tool support, a program called tcpreplay can take that data and feed it back in a variety of ways. Of course, you can modify the file first — there are tools to make that easier and — if you need to — you can craft your own network traffic by hand or using one of a variety of tools. This process is often called “packet crafting.”

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Disney Imagineering’s “Project Kiwi” Bears Groot

April 26, 2021 by 31 Comments

Some days, we might be forgiven for believing Boston Dynamics has cornered the market on walking robots. They (and other players) are making incredible progress in their field, but three years ago Disney, trying to create autonomous, free-walking robotic actors for some of their more diminutive film characters, found none of the existing platforms were appropriate. So they set their Imagineering department to work on “Project Kiwi”, and we are now seeing the fruits of those efforts.

Research on bipedal robots has amassed over the years, and as the saying goes, if these Imagineers saw further it was by standing on the shoulders of larger robotic platforms. However, the Project Kiwi designers have made a laundry list of innovations in their process of miniaturization, from the “marrow conduit” cooling system which forces air through hollow bones, to gearing that allows actuators to share motors even across joints. The electronics are distributed around the skeleton on individual PCBs with ribbon flex cables to reduce wiring, and almost every component is custom fabricated to meet the complex size and weight requirements.

Even in this early prototype, Disney’s roots in life-like animatronics are evident. Groot’s movements are emotive, if a bit careful, and software can express a variety of personalities through his gaits and postures. The eyes and face are as expressive as we’ve come to expect (though a keen eye for seams puts off some definite Westworld vibes). Reportedly, this version can handle gentle shoves and contact, but we do spot a safety cable still attached to the head. So there’s probably some way to go before we’ll see this interacting with the general public in a park.

Disney’s Imagineering department has been doing some amazing work with robotics and they continue to make significant innovations in the more traditional fields of animatronics. It certainly looks like one of the coolest places to work right now, and now we’re itching to build our own bipedal friends to play with.

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Blocking Out The Sun: Viable Climate Countermeasure Or Absolute Madness?

April 26, 2021 by 155 Comments

If there’s one thing humans hate, it’s exercising willpower. Whether its abstaining from unhealthy foods, going to bed early, or using less energy and reducing greenhouse gas emissions, we’re famously bad at it. Conversely, if there’s one thing humans love, it’s a workaround. Something that lets us live our lives as the carefree hedonists we are, and deals with the sticky consequences so we don’t have to.

One such workaround for the issue of climate change is a doozy, though — blocking out the sun’s rays in order to cool our warming planet.

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Build An ESP32 Stock Ticker To Watch Your GME Gains

April 26, 2021 by 14 Comments

Meme investing is all the rage these days, and what better way to get in on the loss fun than with your very own old-timey mechanical stock ticker? Unfortunately, they’re about as expensive and rare as you might expect for a piece of Victorian-era electronics. Lucky for us, [secretbatcave] has shown that you can put together a functional look-alike that costs about as much as a GameStop (GME) share was worth before it started heading to the Moon.

This might seem like an ambitious project, but in actuality the machine only has a few moving parts. There’s a stepper motor to feed the paper, another to spin an inked embossing wheel, and a couple of solenoids attached to a pusher plate. Rather than trying to move the heavy wheel, the pusher plate smashes the paper up into it. The fact that this produces a satisfying “clack” sound as each character is printed is just an added bonus.

Extending the base to hold the solenoids.

To sell the look, [secretbatcave] put the whole mechanism inside a tall glass dome from IKEA. The matching wooden base was extended so the pusher plate solenoids could fit inside, after which it was dunked in ink and sprayed with a gloss sealer to give it that shiny black finish people seemed to love in the 1900s. With the addition of an engraved brass nameplate, it looks like the machine fell out of a time warp.

In terms of electronics, there’s an ESP32, a pair of stepper motor controllers, and a relay for the solenoids. As of right now it all lives in a rather utilitarian box that’s tethered to the ticker, but we’re sure the lot could get tucked under the base with the help of a custom PCB should you be so inclined.

With an ESP32 at the helm, the ticker could easily be configured to print out whatever data it receives over the network or picks up from MQTT. With hardware like this and a pair of Diamond Hands, those tendies are as good as yours.

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3D-Printed Laser Scanning Confocal Microscope Measures Microns

April 26, 2021 by 15 Comments

When one thinks about microscopy, it seems to be mostly qualitative. Looking at a slide teeming with bacteria or protozoans is less about making measurements and more about recognizing features and describing their appearance. Not all microscopes are created equal, though, with some being far more optimized for making fine measurements of the microscopic realm.

This 3D-printed confocal laser scanning microscope is a good example of an instrument for measuring really small stuff. As [Zachary Tong] points out, confocal scanning microscopy uses a clever optical setup to collect light from a single, well-defined point within a sample; rather than getting an image of all the points within a two-dimensional focal plane, the scanning function moves the focal point around through the sample in three dimensions, capturing spatial data to go along with the optical information.

The stage of [Zach]’s microscope is based on OpenFlexure’s Delta Stage, an open-source, 3D-printed delta-bot motion control platform that’s capable of positioning samples with sub-micron precision. Above the stage are the deceptively simple optics, with a laser diode light source, an objective lens, and a photodiode detector behind a pinhole. The detector feeds a homebrew trans-impedance amplifier that captures data at millions of points as the sample is moved through a small three-dimensional space. All that data gets crunched to find the Z-axis position corresponding to the maximum intensity at each point.

It takes a while to gather all this data — up to several days for even a small sample — but it works pretty well. [Zach] already has some ideas for reducing noise and speeding up the scan time; perhaps a stage based on DVD parts like this one would be faster than the delta stage. We look forward to seeing his improvements.

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Keep In Touch With Grandma, With This Lo-Tech Interface

April 25, 2021 by 17 Comments

We have so many options through which to communicate with our friends and relatives during the lockdown, thanks to our smartphones and the number of apps that serve all possible needs. Impressive as they are though, a smartphone is not suitable for everyone. In particular older people can find them less easy to use, and the consequent loss of communication ability is addressed by [Manu] with the Yayagram, described in a thread of Spanish-language Tweets and later the thread was translated into English.

On the top of the box is a microphone with push-to-talk switch, a small thermal printer, and a set of 1/4″ jack sockets with associated jump lead. Each socket corresponds to a relative, and an audio message to that relative can be posted via Telegram simply by speaking into the microphone with the button pressed. Replies are then printed through the thermal printer. Meanwhile behind the scenes is a Raspberry Pi holding it all together.

We like the simplicity of the interface, and who wouldn’t want to ensure that their older relatives were able to keep in touch! But while the jump lead is a neat touch, we hope it’s not too difficult for extremely frail hands. It’s certainly not the first accessibility project for older people that we’ve seen.

Small Open Source Vehicle Hacking Platform

April 25, 2021 by 9 Comments

[Florian] and his engineering team at Munich-based bmc::labs has developed a clever set of prototyping boards for vehicle hacking and rapid product development, collectively called the bmc::board or bmc::mini. These stackable development boards were initially designed for in-house use. The team took a general purpose approach to the design so the boards could be used across a wide range of projects, and they should be useful to anyone in the field. [Florian] decided to release the boards to the community as open-source and certified by OSHWA (Open Source Hardware Association).

There are four boards currently defined, with several more in the works:

  • mini::base — Main microcontroller board, STM32F103-based
  • mini::out — I/O board with CAN bus, JTAG, etc.
  • mini:: grid — RF board providing GPS and GSM capability
  • mini::pit — local wireless connectivity, WiFi and Bluetooth, and 2nd CAN bus

At 54 x 42.5 mm, these boards are pretty small; a form-factor they describe as “exactly half a credit card”. We like the Wurth WR-MM family of stacking connectors they are using, and the symmetrical pinout means you can rotate the cards as needed. But at first glance, these thru-hole connectors seem to limit the stack to just two boards, although maybe they plan move to an SMT flavor of the connector in future designs permitting taller stacks.

If you’re into vehicle electronics and/or vehicle hacking, definitely take a look at these. You can check out [Florian]’s bmc::board Hackaday.io project page and the team’s GitHub repository for more details. Here’s another project by team member [Sebastian] using one of the future bmc::bike modules to eavesdrop on ECU communications, where he sensibly advises the reader “First, pull over and get off the bike. Never hack a two-wheeled vehicle while riding it!”.

No discussion of vehicle CAN bus tools should omit the work of Craig Smith, who literally wrote the book on hacking your car, and whose talk along with Hackaday’s own Eric Evenchick of CANtact fame we covered back in 2016. [Florian] has started a CrowdSupply campaign where you can see some more details of this project and a short promotional video.