A pinout diagram of the new Pi 4, showing all the alternate interfaces available.

Did You Know That The Raspberry Pi 4 Has More SPI, I2C, UART Ports?

February 1, 2022 by Arya Voronova 35 Comments

We’ve gotten used to the GPIO-available functions of Raspberry Pi computers remaining largely the same over the years, which is why it might have flown a little bit under the radar: the Raspberry Pi 4 has six SPI controllers, six I2C controllers, and six UARTs – all on its 40-pin header. You can’t make use of all of these at once, but with up to four different connections wired to a single pin you can carve out a pretty powerful combination of peripherals for your next robotics, automation or cat herding project.

The datasheet for these peripherals is pleasant to go through, with all the register maps nicely laid out – even if you don’t plan to work with the register mappings yourself, the maintainers of your preferred hardware enablement libraries will have an easier time! And, of course, these peripherals are present on the Compute Module 4, too. It might feel like such a deluge of interfaces is excessive, however, it lets you achieve some pretty cool stuff that wouldn’t be possible otherwise.

Having multiple I2C interfaces helps deal with various I2C-specific problems, such as address conflicts, throughput issues, and mixing devices that support different maximum speeds, which means you no longer need fancy mux chips to run five low-resolution Melexis thermal camera sensors at once. (Oh, and the I2C clock stretching bug has been fixed!) SPI interfaces are used for devices with high bandwidth, and with a few separate SPI ports, you could run multiple relatively high-resolution displays at once, No-Nixie Nixie clock style.

As for UARTs, the Raspberry Pi’s one-and-a-half UART interface has long been an issue in robotics and home automation applications. With a slew of devices like radio receivers/transmitters, LIDARs and resilient RS485 multi-drop interfaces available in UART form, it’s nice that you no longer have to sacrifice Bluetooth or a debug console to get some fancy sensors wired up to your robot’s brain. You can enable up to six UARTs. Continue reading “Did You Know That The Raspberry Pi 4 Has More SPI, I2C, UART Ports?” →

Musical Cyberdeck Is Part Synth, Part MIDI Controller, And All Cool

September 9, 2021 by Dan Maloney 3 Comments

When a new project type starts to get a lot of exposure, it’s typically not long before we see people forking the basic concept and striking out in a new direction. It happened with POV displays, it happened with Nixie clocks, and now, it seems to be happening with cyberdecks. And that’s something we can get behind, especially with cyberdecks built to suit a specialized task, like this musical cyberdeck/synth.

Like many musicians, [Benjamin Caccia] felt like he needed a tool to help while performing with his band “Big Time Kill.” He mainly needed to trigger track playbacks on the fly, but also wanted something to act as a mega-effects pedal and standalone synth. And while most of that could be done with an iPad, it wouldn’t look as cool as a cyberdeck. The build centers around a Raspberry Pi 4 and a 7″ LCD display. Those sit on top of a 25-key USB MIDI keyboard and a small mixer. Alongside the keyboard is a USB keypad, which has custom mappings to allow fast access to buried menu functions in the cyberdeck’s Patchbox OS. Everythign was tied together on a 3D-printed frame; the video below shows it in action, and that it sounds as good as it looks.

We think [Benjamin]’s cyberdeck came out great. Need to see some other specialized cyberdecks? Why not take a look at this battle-ready cyberdeck, one that aims to be distraction-free, or a cyberdeck for patrolling the radioactive wastelands.

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This Horrifying Robot Is Here To Teach You A Lesson

July 1, 2021 by Tom Nardi 8 Comments

No, despite what it might look like, this isn’t some early Halloween project. The creepy creation before you is actually a tongue-in-cheek “robot” created by the prolific [Nick Bild], a topical statement about companies asking their remote workers to come back into the office now that COVID-19 restrictions are being lifted. Why commute every day when this ultra realistic avatar can sit in for you?

OK, so maybe it’s not the most impressive humanoid creation to ever grace the pages of Hackaday. But if you’re looking to spin up a simple telepresence system, you could do worse than browsing through the Python source code [Nick] has provided. Using a Raspberry Pi 4, a webcam, and a microphone, his client-server architecture combines everything the bot sees and hears into a simple page that can be remotely accessed with a web browser.

Naturally this work from home (WFH) bot wouldn’t be much good if it was just a one-way street, so [Nick] has also added a loudspeaker that replays whatever he says on the client side. To prevent a feedback loop, his software includes a function that toggles which direction the audio stream goes in by passing the appropriate commands to the bot over SSH; a neat trick to keep in mind for your own, less nightmarish, creations.

If you’re looking for something a bit more capable and have some cardboard laying around, this DIY telepresence mount for your phone might be a good place to start.

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Reachy The Open Source Robot Says Bonjour

January 14, 2021 by Roger Cheng 11 Comments

Humanoid robots always attract attention, but anyone who tries to build one quickly learns respect for a form factor we take for granted because we were born with it. Pollen Robotics wants to help move the field forward with Reachy: a robot platform available both as a product and as a wealth of information shared online.

This French team has released open source robots before. We’ve looked at their Poppy robot and see a strong family resemblance with Reachy. Poppy was a very ambitious design with both arms and legs, but it could only ever walk with assistance. In contrast Reachy focuses on just the upper body. One of the most interesting innovations is found in Reachy’s neck, a cleverly designed 3 DOF mechanism they called Orbita. Combined with two moving antennae at the top of the head, Reachy can emote a wide range of expressions despite not having much of a face. The remainder of Reachy’s joints are articulated with Dynamixel serial bus servos though we see an optional Orbita-based hand attachment in the demo video (embedded below).

Reachy’s € 19,990 price tag may be affordable relative to industrial robots, but it’s pretty steep for the home hacker. No need to fret, those of us with smaller bank accounts can still join the fun because Pollen Robotics has open sourced a lot of Reachy details. Digging into this information, we see Reachy has a Google Coral for accelerating TensorFlow and a Raspberry Pi 4 for general computation. Mechanical designs are released via web-based Onshape CAD. Reachy’s software suite on GitHub is primarily focused on Python, which allows us to experiment within a Jupyter notebook. Simulation can be done within Unity 3D game engine, which can be optionally compiled to run in a browser like the simulation playground. But academic robotics researchers are not excluded from the fun, as ROS1 integration is also available though ROS2 support is still on the to-do list.

Reachy might not be as sophisticated as some humanoid designs we’ve seen, and without a lower body there’s no way for it to dance. But we are very appreciative of a company willing to share knowledge with the world. May it spark new ideas for the future.

[via Engadget]

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A Tubular Fairy Tale You Control With Your Phone

January 6, 2021 by Kristina Panos 1 Comment

At first glance, this might appear to be a Rube Goldberg machine made of toys. The truth isn’t far off — it’s a remote-control animatronic story machine driven by its spectators and their phones. [Niklas Roy] and a team of volunteers built it in just two weeks for Phaenomenale, a festival centered around art and digital culture that takes place every other year.

A red ball travels through a network of clear acrylic tubes using 3D printed Venturi air movers, gravity, and toys to help it travel. Spectators can change the ball’s path with their phones via a local website with a big picture of the installation. The ball triggers animations along its path using break beam detection and weaves a different story each time depending on the toys it interacts with.

Here’s how it works: a Raspberry Pi 4 is responsible for releasing the ball at the beginning of the track and for controlling the track switches. The Pi also hosts a server for smartphones and the 25 Arduino Nanos that control the LEDs and servos of the animatronics. As a bonus animatronic, there’s a giant whiteboard that rotates and switches between displaying the kids’ drawings and the team’s plans and schematics. Take a brief but up-close tour after the break.

This awesome art project was a huge collaborative effort that involved the people of Wolfsburg, Germany — families in the community donated their used and abandoned toys, groups of elementary school kids were brought in to create stories for the toys, and several high school kids and other collaborators realized these drawings with animatronics.

Toys can teach valuable lessons, too. Take this body-positive sushi-snarfing Barbie for example, or this dollhouse of horrors designed to burn fire safety into children’s brains.

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ARM And X86 Team Up In No Compromise Cyberdeck

December 5, 2020 by Tom Nardi 19 Comments

Over the last couple of years the cyberdeck community has absolutely exploded. Among those who design and build these truly personal computers there are no hard rules, save perhaps making sure the final result looks as unconventional as possible. But one thing that’s remained fairly consistent is the fact that these machines are almost exclusively powered by the Raspberry Pi. Unfortunately, that means they often leave something to be desired in terms of raw performance.

But [MSG] had a different idea. His cyberdeck still has the customary Raspberry Pi inside, but it also has an i7 Intel NUC that can be fired up at the touch of a button. He says it’s the best of both worlds: an energy efficient ARM Linux platform for mobile experimentation, and a powerful x86 Windows box for ~~playing games~~ working from home. It’s the hacker equivalent of business in the front, party in the back.

With a KVM connected to the custom Planck 40% mechanical keyboard and seven inch LCD, [MSG] can switch between both systems on the fly. Assuming he’s got the juice anyway; while the Raspberry Pi 4 and LCD is able to run on a pair of 18650 batteries, the cyberdeck needs to be plugged in if he wants to use the power-hungry NUC. If he ditched the Pi he could potentially load up the case with enough batteries to get the Intel box spun up, but that would be getting a little too close to a conventional laptop.

The whole plurality theme doesn’t stop at the computing devices, either. In addition to the primary LCD, there’s also a 2.13 inch e-paper display and a retro-style LED matrix courtesy of a Pimoroni Micro Dot pHAT. With a little Python magic behind the scenes, [MSG] is able to display things like the system temperature, time, and battery percentage even when the LCD is powered down.

In a post on the aptly-named Cyberdeck Cafe, [MSG] talks about how seeing the VirtuScope built by [bootdsc] inspired him to start working towards his own personal deck, and where he hopes to take the idea from here. The unique USB expansion bay behind the screen holds particular promise, and it sounds like a few add-on modules are already in the works. But of course, it wouldn’t be a true cyberdeck if it wasn’t constantly being improved and redesigned. Come to think of it, that makes at least two rules to live by in this community.

A Crust-Cutting, Carrot-Chopping Robot

November 30, 2020 by Kristina Panos 9 Comments

[3DprintedLife] sure does hate bread crust. Not the upper portion of homemade bread, mind you — just that nasty stuff around the edges of store-bought loaves. Several dozen hours of CAD later, [3DprintedLife] had themselves a crust-cutting robot that also chops vegetables.

This De-Cruster 9000 is essentially a 2-axis robotic guillotine over a turntable. It uses a Raspberry Pi 4 and OpenCV to seek and destroy bread crusts with a dull dollar store knife. Aside from the compact design, our favorite part has to be the firmware limit switches baked into the custom control board. The stepper drivers have this fancy feature called StallGuard™ that constantly reads the back EMF to determine the load the motor is under. If you have it flag you right before the motor hits the end of the rail and stalls, bam, you have a firmware limit switch. Watch it remove crusts and chop a lot of carrots with faces after the break.

This is far from the dangerous-looking robot we’ve seen lately. Remember this hair-cutting contraption?

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