This Raspberry Pi Is A Stereo Camera And So Much More

December 30, 2018 by 27 Comments

Over the years we have featured a huge array of projects featuring the Raspberry Pi, but among them there is something that has been missing in all but a few examples. The Raspberry P Compute Module is the essentials of a Pi on a form factor close to that of a SODIMM module, and it is intended as a way to embed a Pi inside a commercial product. It’s refreshing then to see [Eugene]’s StereoPi project, a PCB that accepts a Compute Module and provides interfaces for two Raspberry Pi cameras.

What makes this board a bit special is that as well as the two camera connectors at the required spacing for stereophotography it also brings out all the interfaces you’d expect on a regular Pi, so there is the familiar 40-pin expansion header as well as USB and Ethernet ports. It has a few extras such as a pin-based power connector, and an on-off switch.

Where are they going with this one? So far we’ve seen demonstrations of the rig used to create depth maps with ROS (Robot Operating System). But even more fun is seeing the 3rd-person-view rig shown in the video below. You strap on a backpack that holds the stereo camera above your head, then watch yourself through VR goggles. Essentially you become the video game. We’ve seen this demonstrated before and now it looks like it will be easy to give it a try yourself as StereoPi has announced they’re preparing to crowdfund.

So aside from the stereophotography why is this special? The answer comes in that it is as close as possible to a fresh interpretation of a Raspberry Pi board without being from the Pi Foundation themselves. The Pi processors are not available to third party manufacturers, so aside from the Odroid W (which was made in very limited numbers) we have never seen a significant alternative take on a compatible Raspberry Pi. The idea that this could be achieved through the Compute Module is one that we hope might be taken up by other designers, potentially opening a fresh avenue in the Raspberry Pi story.

The Raspberry Pi Compute Module has passed through two iterations since its launch in 2014, but probably due to the lower cost of a retail Raspberry Pi we haven’t seen it in many projects save for a few game consoles. If the advent of boards like this means we see more of it, that can be no bad thing.

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3D-Printing Wankel Engine From Mazda’s Beloved “Rotary Rocket”

December 30, 2018 by 30 Comments

Although there was briefly a company called Rotary Rocket, the term is much better known as a nickname for the Mazda RX-7 — one of the few cars that used a Wankel, or rotary, engine. If you ever wondered how these worked, why not print a model? That’s what [Engineering Explained] did. They printed a 1/3 scale model and made a video explaining and demonstrating its operation. The model itself was from Thingiverse, created by [EricThePoolBoy].

One thing we really liked about the model was the use of lights to show the different stages of combustion. Cool air intake is a blue light, hot air is red, and so on. It really helps visualize what’s happening. You can watch the video below.

If you haven’t seen a Wankel before, it is a clever design. It has very few moving parts and offers very smooth power transfer and high power to weight ratio. The downside, though, is that the engine deliberately burns oil to lubricate and seal, so it is difficult to meet emission standards and requires a lot of oil. The fuel efficiency of current designs is not very good either, especially since manufacturers will often trade fuel efficiency for better emissions.

If you’d like to read more about the Wankel, check out our earlier post (and the 165 comments attached). We also looked at — or rather through — another Wankel earlier this year.

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Turning LEGO Blocks Into Music With OpenCV

December 30, 2018 by 2 Comments

We’re not sure what it is, but something about LEGO and music go together like milk and cookies when it comes to DIY musical projects. [Paul Wallace]’s Lego Music project is a sequencer that uses the colorful plastic pieces to build and control sound, but there’s a twist. The blocks aren’t snapped onto anything; the system is entirely visual. A computer running OpenCV uses a webcam to watch the arrangement of blocks, and overlays them onto a virtual grid where the positions of the pieces are used as inputs for the sequencer. The Y axis represents pitch, and the X axis represents time.

Embedded below are two videos. The first demonstrates how the music changes based on which blocks are placed, and where. The second is a view from the software’s perspective, and shows how the vision system processes the video by picking out the colored blocks, then using their positions to change different values which has an effect on the composition as a whole.

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POV Tops Hobbyist Abilities

December 29, 2018 by 11 Comments

Sometimes a beautiful project is worth writing on that merit alone, but when it functions as designed,someone takes the time to create a thorough and beautiful landing page for their project, we get weak in the knees. We feel the need to grab the internet and point our finger for everyone to see. This is one of those projects that checks all our boxes. [Nathan Petersen] made a POV toy top called Razzler, jumping through every prototyping hoop along the way. The documentation he kept is what captured our hearts.

The project is a spinning top with an integrated persistence-of-vision (POV) display. That’s the line of LEDs that you see here. To sync up the patterns, the board includes an IMU, but detecting angular velocity with either gyroscope or accelerometer proved problematic. [Nathan’s] writeup of this is worth the read itself, but you’ll also enjoy the CNC workworking part of the project used to create the body of the spinning top.

This was [Nathan]’s first big solo project, and so many of the steps are explained by someone who just entered the deep-end very quickly. If you have experience, you may grin at the simplified reasonings, but for a novice, it makes for an approachable lesson. The way he selects hardware and firmware is pragmatic and perhaps even overkill, so you know he’s going into engineering. This overshot saved him when there were communication problems which needed a sacrifice of some processing power to run I2C on some GPIO.

We hope you enjoy reading about this combinations of POV, firmware (or is it?), and centrifugal force.

Infinity Cube Is Gorgeous Yet Simple

December 29, 2018 by 23 Comments

Typically when we hear the words “LED” and “Cube”, we think of small blinking devices on protoboard designed to flex one’s programming and soldering skills. However, while [Heliox]’s Cube Infini could be described as “a cube of LEDs”, it’s rather a different beast (video in French, subtitles available).

The cube starts with a 3D printed frame, designed in Fusion 360. The devil really is in the details — [Heliox] puts in nice touches, such as the artistic cube relief on the base, and the smart integrated cable management in the edges. The faces of the cube are plexiglass sheets, covered with a one-way reflective film that is applied in a similar manner to automotive window tint. For lighting, a high-density LED strip is fitted to the inside edges, chosen for maximum visual effect. It’s controlled by an IR remote and a cheap control module from Amazon.

While the build contains no particularly advanced tools, materials, or techniques, the final result is absolutely stunning. It’s a piece we’d love to have as a lamp in a stylish loungeroom or study. [Heliox] does a great job of explaining how the cube is designed and fits together, and it’s a testament to just what can be achieved with a little ingenuity and hard work.

Once you’re done here, check out this ping-pong based build.

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Homemade Daft Punk Helmet

December 29, 2018 by 2 Comments

You may not be French, and you may not have had a series of hit records, but you can still have the blinky LED helmet, thanks to this build from [Electronoobs]. They have put together a neat Daft Punk helmet built from 3D printed parts, an Arduino, a Bluetooth module, a string of WS2812 addressable LEDs and a simple app. The helmet itself is 3D printed, and the Arduino, Bluetooth, and battery are mounted in the chin. The LED panel is a series of WS2812 LED light strips wired together in series. The whole thing is controlled over a Bluetooth connection to an Android app that was built with the MIT App Inventor.

It’s a nice, simple build, but as we’ve discussed before choosing diffusers is hard. We’re not sure if a thicker panel covering the LED strips, or flipping the LEDs over and adding a reflective layer would be the right moves to improve upon the diffused look. Either way, it’s a neat place to start with your own build and a good way to learn about how to have fun with LED strips.

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Open Source IDE For FPGAs As QtCreator Learns Verilog

December 29, 2018 by 10 Comments

Classic battles: PC vs Mac, Emacs vs Vi, Tastes Great vs Less Filling, and certainly one that we debate around the Hackaday watercooler: command line or IDE? There’s something to be said for using good old command line tools, and even if you like to configure your favorite editor to be nearly an IDE, at least it is one you are familiar with and presumably leverage over several different uses.

Most commercial FPGA tools come with a heavy-weight IDE. The open source tools for Lattice (IceStorm) typically is driven by the command line or a makefile. Until now. [Rochus-Keller] released VerilogCreator which is a plugin for QtCreator.

We were impressed because as IDEs go, QtCreator is both useful and lightweight, two things that don’t go together for many similar tools. [FPGAwars] has had an IDE based on Atom (apio-ide) although it hasn’t been updated in nearly a year. IceStudio sees more updates, of course, but it isn’t so much an IDE as a GUI-based code builder.

[Rochus-Keller] says there’s more to come. However, even at this early stage the IDE does syntax coloring, tooltips, inline messages, and can analyze source code allowing you to cross-reference symbols as you’d expect. There are configurations for Icarus to do simulations or you can use Verilator or Yosys — the synthesizer behind IceStorm. It appears it can also interact with Tcl-based workflows like those used by most FPGA vendor IDEs.

There’s quite a bit still on the to-do list, so we are excited to see where this is going. QtCreator isn’t hard to learn and it doesn’t’ feel as bloated as some of the big IDEs like Eclipse. If you want a quick introduction to QtCreator, we did that already. If you want to draw boxes instead of writing Verilog directly, try IceStudio.