The Adorable Robot Spot, Now In Affordable Form

October 23, 2020 by Erin Pinheiro 8 Comments

If you’ve been following the Boston Dynamics project Spot, you’ve seen its capabilities and how we’re starting to see it being used in public more since its official release last year. But in a true display of how hobbyist electronics have been evolving and catching up with the big companies over the past few years, [Miguel Ayuso Parrilla] shows us his own take on the walking robot with CHOP, one of the finalists in this year’s Hackaday Prize.

CHOP is a DIY quadruped robot that works much in the same way as Spot, although in a smaller form-factor and, perhaps most impressive of all, a bill of materials that can be all acquired for under $500. The entire project is open source, meaning that anyone can built their own version of it with off-the-shelf parts and some 3D printing. If you can’t get the hardware however, you can still play with the PyBullet simulation of the mechanics that were used during the debugging process.

Running the show are two main components, a Raspberry Pi 4B and an Arduino Mega. While the Mega interfaces with the servo controllers and provides filtering for sensors like the inertial measurement unit, the Pi takes all that data in and uses a series of Python scripts in order to determine the gait of the robot and which way the servos should move through an inverse kinematics model. To control the direction in which the body of the robot should accelerate, a Bluetooth remote controller sends commands to the Raspberry Pi.

We’re excited to see home-grown projects rise to this level of complexity, which would be mostly unheard of a few years ago in the maker scene, and only presented by large tech companies with tons of money to spend on research and development. There are other quadruped robots to inspire yourself on than Spot though, like this one with a spherical design and fold-out legs. Check this one in action after the break.

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Affordable Ground-Penetrating Radar

October 22, 2020 by Bryan Cockfield 30 Comments

While you might think of radar pointing toward the skies, applications for radar have found their way underground as well. Ground-penetrating radar (GPR) is a tool that sends signals into the earth and measures their return to make determinations about what’s buried underground in much the same way that distant aircraft can be located or identified by looking for radar reflections. This technology can also be built with a few common items now for a relatively small cost.

This is a project from [Mirel] who built the system around a Arduino Mega 2560 and antipodal Vivaldi antennas, a type of directional antenna. Everything is mounted into a small cart that can be rolled along the ground. A switch attached to the wheels triggers the radar at regular intervals as it rolls, and the radar emits a signal and listens to reflections at each point. It operates at a frequency range from 323 MHz to 910 MHz, and a small graph of what it “sees” is displayed on an LCD screen that is paired to the Arduino.

Using this tool allows you to see different densities of materials located underground, as well as their depths. This can be very handy when starting a large excavation project, detecting rock layers or underground utilities before digging. [Mirel] made all of the hardware and software open-source for this project, and if you’d like to see another take on GPR then head over to this project which involves a lot of technical discussion on how it works.

Grab A Stanford Computer Science Education

October 14, 2020 by Al Williams 18 Comments

There are two reasons to go to school: learn about something and to get a coveted piece of paper that helps you get jobs, or at least, job interviews. With so many schools putting material online, you can do the first part without spending much money as long as you don’t expect the school to help you or grant you that piece of paper. Stanford has a huge computer science department and [Rui Ma] cataloged over 150 computer science classes available online in some form from the University. Just the thing to while away time during the quarantine.

Apparently, [Rui] grabbed the 2020 course catalog to find on-campus classes and found the companion website for each class, organizing them for our benefit. The list doesn’t include the actual online class offerings, which you can find directly from Stanford, although there is another list for that.

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Aruna: An Open Source ROV For Affordable Research

October 7, 2020 by Tom Nardi 19 Comments

Underwater exploration and research can be exceedingly dangerous, which is why remotely operated vehicles (ROVs) are so commonly used. Operators can remotely command these small submersibles to capture images or collect samples at depths which would otherwise be unreachable. Unfortunately, such technology comes at a considerable price.

Believing that the high cost of commercial ROVs is a hindrance to aquatic conservation efforts, [Noeël Moeskops] has been developing an open source modular ROV he calls Aruna. Constructed largely from off-the-shelf components and 3D-printed parts, the Aruna promises to be far more affordable than anything currently on the market. Hopefully cheap enough to allow local governments and even citizens to conduct their own underwater research and observations.

More than just the ROV itself, Aruna represents an entire system for developing modular underwater vehicles. Whether you decide to build the boilerplate ROV documented and tested by [Noeël], or implement individual components into your own design, the project is a valuable source of hardware and software information for anyone interested in DIY underwater robotics.

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Building An Affordable Press For Heat Set Inserts

September 9, 2020 by Tom Nardi 11 Comments

If you’re building mechanical assemblies with 3D printed parts, you’ll quickly realize that driving machine screws into thermoplastic isn’t exactly an ideal solution. It can work in a pinch, but you can easily strip the threads if you crank down too hard. The plastic holes can also get worn down from repeated use, which is a problem if you’re working on something that needs to be taken apart and reassembled frequently. In those situations, using brass heat set inserts gives the fasteners something stronger to bite into.

You can install these inserts by hand, but if you plan on doing a lot of them, a dedicated press station like the one [Chris Chimienti] recently put together will save you a lot of aggravation in the long run. In the video after the break he walks viewers through the design and use of the device, which itself relies on a number of 3D printed parts using the very same inserts it’s designed to install.

The spring-loaded arm can slide up and down the extrusion to adjust for height.

To build this tool you’ll need a piece of aluminum extrusion, some smooth rod, a couple springs, and an assortment of fasteners. Nothing that wouldn’t likely be in the parts bin of anyone who’s been tinkering with 3D printers for awhile, though even if you had to buy everything, the Bill of Materials will hardly break the bank. For the base you can use a piece of scrap wood, though [Chris] has opted to make it a storage compartment where he can store the inserts themselves. We really like this approach, but obviously you’ll need to have access to woodworking tools in that case.

Clearly shopping on the top shelf, [Chris] purchased a kit that actually came with a Weller soldering iron and the appropriate tips for the various sized inserts. If you’re like us and just buy the inserts that come in a plastic baggie, you may need to adapt the arm to fit your iron of choice. That said, the idea of having a dedicated iron that you can leave mounted in the press makes a lot of sense to us if you can swing it.

[Joshua Vasquez] wrote up a phenomenal guide to getting started with heat set inserts last year that’s an absolute must-read for anyone interested in the concept. Whether you build a dedicated press or just push them in freehand, his tips and tricks will help insure you get the best result possible.

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IRobot Makes Learning Robot More Affordable

August 6, 2020 by Al Williams 10 Comments

When you think of iRobot, you probably think of floor cleaning or military robots. But they also have a set of robots aimed at education. The Root robot — an acquisition the company made in 2019 — originally targeted classrooms and cost about $200 each. A new version costs about $130 and is a better fit for home users.

The original version — Root rt1 — is still available, but the rt0 version has several missing features to hit the desired price. What’s missing? Apparently, the rt1 can stick to a whiteboard using magnets, but that feature is missing on the rt0. There are also no “cliff” sensors or color scanner.

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An Affordable Home Made Vacuum Chamber

June 29, 2020 by Jenny List 31 Comments

The term “vacuum” means many different things depending whether you are working on space equipment, scientific instruments, or even internal combustion engines. In our sphere it is so often used as a means to draw bubbles out of resin castings, for which it is a relatively easily achievable partial vacuum. It’s something [Fab] is using, in a vacuum chamber made from Plexiglass.

A simple Plexiglass box would collapse under the air pressure on its own, so to mitigate that it’s made from a piece of tube, and with an internal frame of aluminium extrusion with 3D printed joints to strengthen it from the inside. A pressure sensor allows regulation of the pump that drives the vacuum, and connections are made to the chamber using pneumatic hose connectors. It’s not immediately clear how it is sealed, whether there are nay gaskets or other sealant, or whether air pressure pushing the parts together provides enough of a seal.

We’ve featured a lot of vacuum chambers made for this purpose over the years, and we’d be interested to know what vacuum pump is being used here. If you’re curious too and want to build your own, perhaps you could try a fridge compressor.