Author: Donald Papp

381 Articles

Robotics Controller For The Pi Boasts An Impressive Feature List

November 5, 2019 by 4 Comments

[Michael Horne] recently shared his thoughts on the RedBoard+, a motor controller board for the Raspberry Pi aimed at robotic applications. His short version for busy people is: if you’re at all into robotics, get one because it’s fantastic.

At heart the RedBoard+ is a motor controller, but it’s packed with I/O and features that set it above the usual fare. It can drive two DC motors and up to twelve servos, but what is extra useful is the wide input range of 7-24 V and its ability to power and control the underlying Raspberry Pi. A user-programmable button defaults to either doing a reboot or safe shutdown, depending on how long the button is held. Another neat feature is the ability to blink out the IP address of the Pi using the onboard RGB LED, which is always handy in a pinch.

The RedBoard+ has a GitHub repository which provides a variety of test scripts and an easy to use library, as well as a variety of hookup guides and quickstart guides. There’s even a pre-configured SD image for those who prefer to simply dive in.

A brief demo video showing the board in operation is embedded below. If you’re interested in one, Creator [Neil] of RedRobotics has made it available for sale on Tindie.

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Big Beautiful Vintage Computers, And Where To Find Them

October 23, 2019 by 30 Comments
An IBM 3380E disk storage system, 5 gigabyte capacity.

[Ken Shirriff] recently shared some pictures and a writeup from his visit to the Large Scale Systems Museum, a remarkable private collection of mainframes and other computers from the 1970s to the 1990s. Housed in a town outside Pittsburgh, it contains a huge variety of specimens including IBM mainframes and desk-sized minicomputers, enormous disk and tape storage systems, and multiple 90s-era Cray supercomputers. It doesn’t stop there, either. Everything through the minicomputer revolution leading to personal home computers is present, and there are even several Heathkit HERO robot kits from the 80s. (By the way, we once saw a HERO retrofitted with wireless and the ability to run Python.)

Something really special is that many of the vintage systems are in working order, providing insight into how these units performed and acted. The museum is a private collection and is open only by appointment but they encourage interested parties not to be shy. If a trip to the museum isn’t for you, [Ken] has some additional photos from his visit here for you to check out.

Robot Joints Go Modular With This Actuator Project

October 22, 2019 by 4 Comments

[John Lauer] has been hard at work re-thinking robot arms. His project to create modular, open source actuators that can be connected to one another to form an arm is inspiring, and boasts an impressively low parts cost as well. The actuators are each self-contained, with an ESP32 and a design that takes advantage of the form factors of inexpensive modules and parts from vendors like Aliexpress.

Flex spline in action, for reducing backlash

Each module has 3D printed gears (with an anti-backlash flex spline), an RGB LED for feedback, integrated homing, active cooling, a slip ring made from copper tape, and a touch sensor dial on the back for jogging and training input. The result is a low backlash, low cost actuator that keeps external wiring to an absolute minimum.

Originally inspired by a design named WE-R2.4, [John] has added his own twist in numerous ways, which are best summarized in the video embedded below. That video is number three in a series, and covers the most interesting developments and design changes while giving an excellent overview of the parts and operation (the video for part one is a basic overview and part two shows the prototyping process, during which [John] 3D printed the structural parts and gears and mills out a custom PCB.)

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The MorningRod Wants Your Mornings Easier, Not Harder

October 14, 2019 by 19 Comments

Curtains are about as simple as household devices get, but they can be remarkably troublesome to automate. Everyone’s window treatments slightly different, which frustrates a standardized solution. [dfrenkel] has a passion for DIY and wanted his mornings flooded with sunlight for more peaceful awakenings, so the MorningRod Smart Curtain Rod was born.

Replacing the curtain rod with aluminum extrusion and 3D printed fixtures goes a long way towards standardizing for automation.

MorningRod’s design takes advantage of affordable hardware like aluminum extrusions and 3D printed parts to create a system that attempts to allow users to keep their existing curtains as much as possible.

The curtain rod is replaced with aluminum extrusion. MorningRod borrows ideas from CNC projects to turn the curtain rod into a kind of double-ended linear actuator, upon which the curtains are just along for the ride. An ESP32 serves as the brains while a NEMA17 stepper motor provides the brawn. The result is a motorized curtain opening and closing with a wireless interface that can be easily integrated into home automation projects.

[dfrenkel] is offering a kit, but those who would prefer to roll their own should check out the project page on Thingiverse.

DIY Tiny Dovetail Cube Needs DIY Dovetail Cutter

October 10, 2019 by 4 Comments
Dovetail cutter, made from a 5 mm drill rod.

There’s a trinket called a dovetail cube, and [mitxela] thought it would make a fine birthday present. As you can see from the image, he was successful in creating a tiny version out of aluminum and brass. That’s not to say there weren’t challenges in the process, and doing it [mitxela] style means:

  • Make it tiny! 15 mm sides ought to do it.
  • Don’t have a tiny dovetail bit on hand, so make that as well.
  • Of course, do it all without CNC in free-machining style.
  • Whoops the brass stock is smaller than expected, so find a clever solution.
  • That birthday? It’s tomorrow, by the way.

The project was a success, and a few small learning experiences presented themselves. One is that the shape of a dovetail plays tricks on the human eye. Geometrically speaking, the two halves are even but it seems as though one side is slightly larger than the other. [mitxela] says that if he were to do it again, he’d make the aluminum side slightly larger to compensate for this visual effect. Also, deburring with a knife edge on such a small piece flattened the edges ever so slightly, causing the fit to appear less precise than it actually is.

Still, it was a success and a learning experience. Need more evidence that [mitxela] thrives on challenge? Take a look at his incredible vector game console project.

Hacking The IKEA TRÅDFRI LED Power Supply

October 8, 2019 by 22 Comments

Just because something is being actively documented and tampered with by enthusiastic hackers doesn’t mean the information is handily centralized. There can be a lot of value in gathering disparate resources in one place, and that’s exactly what [Trammell Hudson] has done with his resource page for hacking the IKEA TRÅDFRI LED power supply with wireless interface. Schematic teardown, custom firmware images, it’s all there in one convenient spot.

Back in 2017, the IKEA TRÅDFRI hacking scene was centered around the LED light bulbs but as the group of products expanded, the rest of the offerings have also gotten some attention.

Why bother tampering with these units? One reason is to add features, but another is to make them communicate over your own MQTT network. And MQTT is the reason you are only a Raspberry Pi and a trip to IKEA away from the beginnings of a smart home that is under no one’s control or influence but your own.

Pistol Safe’s Poor Design Means Biometric Sensor Bypassed In Seconds

October 3, 2019 by 38 Comments

When it comes to safes, mechanical design and physical layout are just as important as the electronic bits. If care isn’t taken, one element can undermine the other. That appears to be the case with this Amazon Basics branded biometric pistol safe. Because of the mechanical design, the fingerprint sensor can be overridden with nothing more than a thin piece of metal — no melted gummi bears and fingerprint impressions involved.

push button to reset safe fingerprint reader
Small button used to register a new fingerprint. It can be reached by inserting a thin shim in the gap between the door and the frame while the safe is closed and locked.

[LockPickingLawyer] has a reputation for exposing the lunacy of poorly-designed locks of all kinds and begins this short video (embedded below) by stating that when attempting to bypass the security of a device like this, he would normally focus on the mechanical lock. But in this case, it’s far more straightforward to simply subvert the fingerprint registration.

This is how it works: the back of the front panel (which is inside the safe) has a small button. When this button is pressed, the device will be instructed to register a new fingerprint. The security of that system depends on this button being inaccessible while the safe is closed. Unfortunately it’s placed poorly and all it takes is a thin piece of metal slid through the thin opening between the door and the rest of the safe. One press, and the (closed) safe is instructed to register and trust a new fingerprint. After that, the safe can be opened in the usual way.

It’s possible that a pistol being present in the safe might get in the way of inserting a metal shim to hit the button, but it doesn’t look like it. A metal lip in the frame, or recessing the reset button could prevent this attack. The sensor could also be instructed to reject reprogramming while the door is closed. In any case, this is a great demonstration of how design elements can affect one another, and have a security impact in the process.

As for fooling sensors in a more traditional sense, here’s a reminder that we’ve seen a 3D printer and a photo of a fingerprint used to defeat a fingerprint sensor.

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