Robots come in all shapes and sizes, from remote landers on distant planets to assembly arms working hard in auto plants. Of course, the definition is broad and can contain more frivolous entities, too. [smdavee]’s watercoloring ‘bots may not be particularly complex or sentient, but they’re a fun creative build.
The design is akin to that of the BristleBot, with a pager vibration motor allowing the ‘bot to wobble about on unsteady feet. In this case, a keyboard cap is used, with cottontips inserted in the base to act as legs. These are then dipped in watercolor paints, and the attached motor is then switched on to vibrate the ‘bot around the page.
It’s an easy build, and one that would be particularly well-suited to teaching young children basic electronic concepts. Plus, there’s the added fun of getting to make a mess with watercolors, too. If you’ve got a fun art robot hiding away in your garage, be sure to let us know. Video after the break.
If you have ever looked closely at a typical mass-produced automobile, you will be familiar with pressed-steel panels. Complex curves can be repeated thousands of times over, by putting a sheet of steel between shaped tooling in a press and applying huge force. The same work that would take a skilled panel beater weeks to do by hand, in a second. It’s something [Stuff Made Here] tackled when he wanted to wear a set of Crocs in the workshop, and needed to make the tooling to produce them in his hydraulic press. The resulting video which we’ve posted below the break shows his learning curve, and along the way is a handy primer in sheet metal pressing.
We watch as he discovers the properties of sheet metal under the stress of pressing, how it wrinkles and folds, and how the tool needs careful design and the sheet needs to be securely clamped in place to prevent this. The big surprise is that his tooling is made from CNC-machined wood, while we’re sure that it would wear given repeated use it seems that the forces on the tool are not such as to destroy this material. In the end he’s produced a multi-part tool including both halves of the press tool, a machined guide for the moving part, and a set of substantial sheet metal plates to constrain the material. The steel toecap application may not be everyone’s first idea when it comes to sheet metal forming, but we’re sure this technique could find application in many other projects. It’s a territory into which we’ve edged in the past, but never with pressings this complex.
Randomly buying some hackable gadgets just because they are cheap and seem potentially interesting for future projects is something that most of us can relate to. It also happened to [fruchti] when he bought five thermal printer modules without any specific purpose for them in mind. It was not until several years later that he put them to good use for his inverse thermal camera project.
The name perfectly summarizes the device’s function which is to convert images to heat instead of the other way around. To put it in a less cryptic manner, [fruchti] built a selfie camera that instantly prints out pictures on thermochromic paper. The project would have been easy to implement on a Raspberry Pi but instead, he chose a more minimalist approach by using an STM32 microcontroller. This involved some challenges because the MCU didn’t have enough RAM to store an entire frame and the camera module came without a FIFO buffer. To capture and store the image data [fruchti] applied a line-by-line dithering algorithm which is described in detail in his accompanying blog post while the corresponding code is available on GitHub. Even though the case was improvised from scrap PCB materials the finished device still looks great. In particular, the fuse holders that are being used to hold the paper roll make it almost steampunk.
If you do any work with high-speed signals, you quickly realize that probing is an art unto itself. Just having a fast oscilloscope isn’t enough; you’ve got to have probes fast enough to handle the signals you want to see. In this realm, just any old probe won’t do: the input capacitance of the classic RC probe you so often see on low-bandwidth scopes starts to severely load down a circuit well below 1 GHz. That’s why we were really pleased to see [Andrew Zonenberg’s] new open-source design for a 2 GHz resistive probe hit Kickstarter.
The design of this new probe looks deceptively simple. Known as a Z0-probe, transmission-line probe, or resistive probe, the circuit works as a voltage divider, created from the 50-Ohm input impedance of a high-speed oscilloscope input and an external resistor, to reduce loading on the circuit-under-test. In this case, the input resistance has been chosen to be 500 Ohms, yielding a 10x probe. In theory, building such a probe is as simple as soldering a resistor to the end of a piece of coaxial cable. You can do exactly that, but in practice, optimizing a design is much more complex. As you can see in the schematic, just choosing a resistor of the right value doesn’t cut it at these frequencies. Even the tiny 0402-size resistors have parasitic capacitance and inductance that affect the response, and choosing a combination of parts that add to the correct resistance but reduce the overall capacitive loading makes a huge difference.
2 GHz Passive Probe Schematic
Don’t be fooled: the relatively simple schematic belies the complexity of such a design. At these speeds, the PCB layout is just as much of a component as the resistors themselves, and getting the transmission-line and especially the SMA footprint launch correct is no easy task. Using a combination of modeling with the Sonnet EM simulator and empirical testing, [Andrew] has ended up with a design that’s flat (+/- 1 dB) out to 1.98 GHz, with a 10-90% rise time of 161 ps. That’s a fast probe.
The probe comes in a few options, from fully assembled with traceable specs to a DIY solder-it-yourself version. You probably know which of these options you need.
We really like to see this kind of knowledge and thoroughness go into a project, and we’d love to see the Kickstarter project reach its goals, but perhaps the best part is that the design is permissively open-source licensed. This is a case where having the board layout open-sourced is key; the schematic tells you maybe half of what’s really going on in the circuit, and getting the PCB right yourself can be a long and frustrating exercise. So, have a look at the project, and if you haven’t got probes suitable for your fastest scopes, build one, or better yet, support the development of this exciting design.
You’ve always wanted a game console at your bench, but maybe you haven’t had space for a monitor or TV set? Wouldn’t it be useful if the screen you do have on your bench could also play games? [Tube Time] has fixed this problem, with Scopetrex, a vector graphic console for your oscilloscope. In fact, it’s better than just a console, because it’s a clone of the legendary Vectrex, the vector-based console with built-in CRT screen from the 1980s.
The board itself is a slightly enhanced version of the original, offering not extra functionality but the ability to substitute some of the parts for more easily found equivalents. It gives full control over display size and brightness, can use the cheaper 6809E processor and AY-3-9810 sound chip if necessary, and only needs a single 5 volt supply. There’s also a custom controller board, which is handly Vectrex-compatible. All you will need to play Vectrex games on your ‘scope once you’ve built this board, are a copy of the Vectrex ROM, and some games.
Wink Labs just announced that their home automation hub, the Wink Hub, is “transitioning to a $4.99 monthly subscription, starting on May 13, 2020.” Should you fail to pay the fiver every month, you will lose access to their app, voice control, and automations, which is everything it does as far as we can tell.
This is an especially bitter pill to swallow for Hub users, because the device was just that — a hub. It speaks Bluetooth, Z-Wave, ZigBee, WiFi, Kidde, and a couple other specific device protocols, interfaces with Amazon’s Alexa, has a handy Android master panel app, and had a nice “robot” system that made the automation side of “home automation” simple for normal people. In short, with its low one-time purchase price, compatibility with many devices, nice phone app, and multiple radios, it was a great centerpiece for a home-automation setup.
“Nice home automation system you’ve got there. Would be a shame if anything happened to it.”
A robot that performs surgery is a serious thing. One bug in the control system could end with disaster. Unless of course, you’re [Michael Reeves], in which case disaster is all part of the fun. (Video, embedded below.)
Taking inspiration from The da Vinci Surgical System, [Michael] set out to build a system that was faster, while still maintaining precision. He created a belt drive gantry system, not unlike many 3D printers, laser cutters, or woodworking CNC machines. Machines like this often use stepper motors. [Michael] decided to go with [Oskar Weigl’s] ODrive and brushless motors instead. The ODrive is on open source controller which turns off the shelf brushless motors — such as those found in R/C planes or hoverboards, into precision industrial servos. Sound familiar? ODrive was an entrant in the 2016 Hackaday Prize. [Michael] was even able to do away the ubiquitous limit switch by monitoring current draw with the ODrive.
It all adds up to a serious build. But this is [Michael “laser eye” Reeves] after all. The video is meant to be entertaining, with a hidden payload of education and inspiration. The fun starts when he arms the robot with a giant kitchen knife and performs “surgery” on a pineapple. If you want to know what happens when mannequins and fake blood enter the picture, then watch the video after the break.
