New Raspberry Pi 4 Compute Module: So Long SO-DIMM, Hello PCIe!

October 19, 2020 by Elliot Williams 151 Comments

The brand new Raspberry Pi Compute Module 4 (CM4) was just released! Surprised? Nope, and we’re not either — the Raspberry Pi Foundation had hinted that it was going to release a compute module for the 4-series for a long while.

The form factor got a total overhaul, but there’s bigger changes in this little beastie than are visible at first glance, and we’re going to walk you through most of them. The foremost bonuses are the easy implementation of PCIe and NVMe, making it possible to get data in and out of SSDs ridiculously fast. Combined with optional WiFi/Bluetooth and easily designed Gigabit Ethernet, the CM4 is a connectivity monster.

One of the classic want-to-build-it-with-a-Pi projects is the ultra-fast home NAS. The CM4 makes this finally possible.

If you don’t know the compute modules, they are stripped-down versions of what you probably think of as a Raspberry Pi, which is officially known as the “Model B” form-factor. Aimed at commercial applications, the compute modules lack many of the creature comforts of their bigger siblings, but they trade those for flexibility in design and allow for some extra functionality.

The compute modules aren’t exactly beginner friendly, but we’re positively impressed by how far Team Raspberry has been able to make this module accessible to the intermediate hacker. Most of this is down to the open design of the IO Breakout board that also got released today. With completely open KiCAD design files, if you can edit and order a PCB, and then reflow-solder what arrives in the mail, you can design for the CM4. The benefit is a lighter, cheaper, and yet significantly more customizable platform that packs the power of the Raspberry Pi 4 into a low-profile 40 mm x 55 mm package.

So let’s see what’s new, and then look a little bit into what is necessary to incorporate a compute module into your own design.

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Robot Travels The World

October 17, 2020 by Bryan Cockfield 7 Comments

Around the World in 80 Days may have been an impressive feat of international travel in a world before widespread air transit. In modern times though, it’s not even necessary to leave your home in order to travel around the world. To that end, [Norbert] is attempting to accomplish this journey using a robot that will do the traveling for him as part of this year’s Virtual Maker Faire.

The robot is called the World Tour Robot, and the idea for it is to be small enough to ship to each new location around the world and be simple enough to be repaired easily. It is driven by two servo motors and controlled by a Raspberry Pi which also handles a small camera. Once at its location, it can connect to the internet and then be able to be controlled through a web interface. Locations are selected by application, and the robot is either handed off to the next person in the chain or put back in a box to be shipped.

The robot hasn’t left for its maiden voyage just yet but [Norbert] plans to get it started soon. Hopefully there are enough interesting places for this robot to explore on its trip around the world, although it’s probably best to avoid Philadelphia as it is known to be unfriendly to robots.

Cheap All-Sky Camera Is Easy As Pi

October 14, 2020 by Kristina Panos 28 Comments

Combining a Raspberry Pi HQ camera and a waterproof housing, [jippo12] made an all-sky, all-Pi meteorite tracking camera on the cheap, and it takes fantastic photos of the heavens. It’s even got its own YouTube channel. Inside there’s a Raspberry Pi 4 plus an HQ camera to take the pictures. But there’s also a system in place to keep everything warm and working properly. It uses a Raspberry Pi 3+, a temperature sensor, and a relay control HAT to pump pixies through a couple of 10 W resistors, making just enough heat to warm up the dome to keep it from fogging.

A few years ago, we reported that NASA was tracking meteorites (or fireballs, if you prefer) with a distributed network of all-sky cameras — cameras with 360° views of the night sky. Soon after, we found out that the French were doing something quite similar with their FRIPON network. We pondered how cool it would be to have a hacker network of these things, but zut alors! Have you seen the prices of these things? Nice hack, [jippo12]!

Rather do things the old fashioned way? Dust off that DSLR, fire up that printer, and check out OpenAstroTracker.

Running Way More LED Strips On A Raspberry Pi With DMA

October 12, 2020 by Lewin Day 18 Comments

The Raspberry Pi is a powerful computer in a compact form factor, making it highly useful for all manner of projects. However, it lacks some of the IO capabilities you might find on a common microcontroller. This is most apparent when it comes to running addressable LED strings. Normally, this is done using the Pi’s PWM or audio output, and is limited to just a couple of short strings. However, [Jeremy P Bentham] has found a way to leverage the Pi’s hardware to overcome these limitations.

The trick is using the Raspberry Pi’s little-documented Secondary Memory Interface. The SMI hardware allows the Pi to shift out data to 8 or 16 I/O pins in parallel using direct memory access (DMA), with fast and accurate timing. This makes it perfect for generating signals such as those used by WS2812B LEDs, also known as NeoPixels.

With [Jeremy]’s code and the right supporting hardware, it’s possible to run up to 16 LED strips of arbitrary length from the Raspberry Pi. [Jeremy] does a great job outlining how it all works, covering everything from the data format used by WS2812B LEDs to the way cache needs to be handled to avoid garbled data. The hack works on all Pis, from the humble Pi Zero to the powerful Pi 4. Thanks to using DMA, the technique doesn’t overload the CPU, so performance should be good across the board.

Of course, there are other ways to drive a ton of LEDs; we’ve seen 20,000 running on an ESP32, for example.

[Thanks to Petiepooo for the tip!]

Access An 8-bit Atari Through Twitter

October 11, 2020 by Bryan Cockfield 3 Comments

Building a retro computer, or even restoring one, is a great way to understand a lot of the fundamentals of computing. That can take a long time and a lot of energy, though. Luckily, there is a Twitter bot out there that can let you experience an old 8-bit Atari without even needing to spin up an emulator. Just tweet your program to the bot, and it outputs the result.

The bot was built by [Kay Savetz] and accepts programs in five programming languages: Atari BASIC, Turbo-Basic XL, Atari Logo, Atari PILOT, and Atari Assembler/Editor, which was a low-level assembly-type language available on these machines. The bot itself runs on a Raspberry Pi with the Atari 800 emulator, rather than original hardware, presumably because it’s much simpler to get a working network connection on a Pi than on a computer from the 80s. The Pi runs a python script that polls Twitter every two minutes and then hands the code off to the emulator.

[Kay]’s work isn’t limited to just Ataris, though. There’s also an Apple II BASIC bot for all the Apple fans out there that responds to programs written in AppleSoft BASIC. While building your own retro system or emulating one on other hardware is a great exercise, it’s also great that there are tools like these that allow manipulation of retro computers without having to do any of the dirty work ourselves.

Raspberry Pi Crazy Guitar Rig Turns You Into A Hard ‘N Heavy One-Man Band

October 7, 2020 by Sven Gregori 18 Comments

It’s a common problem: you’re at a party, there’s a guitar, and your plan to impress everyone with your Wonderwall playing skills is thwarted by the way too loud overall noise level. Well, [Muiota betarho] won’t have that issue ever again, and is going to steal the show anywhere he goes from now on with his Crazy Guitar Rig 2.0, an acoustic guitar turned electric — and so much more — that he shows off in three-part video series on his YouTube channel. For the impatient, here’s video 1, video 2, and video 3, but you’ll also find them embedded after the break.

To start off the series, [Muiota betarho] adds an electric guitar pickup, a set of speakers, and an amplifier board along with a battery pack into the body of a cheap acoustic guitar. He then dismantles a Zoom MS-50G multi-effect pedal and re-assembles it back into the guitar itself with a 3D-printed cover. Combining a guitar, effect pedal, amp and speaker into one standalone instrument would make this already an awesome project as it is, but this is only the beginning.

Touch screen and controls closeup — RPi touch screen running SunVox, plenty of buttons, and integrated multi-effect pedal on the left

So, time to add a Raspberry Pi running SunVox next, and throw in a touch screen to control it on the fly. SunVox itself is a free, but unfortunately not open source, cross-platform synthesizer and tracker that [Muiota betarho] uses to add drum tracks and some extra instruments and effects. He takes it even further in the final part when he hooks SunVox up to the Raspberry Pi’s GPIO pins. This allows him to automate things like switching effects on the Zoom pedal, but also provides I/O connection for external devices like a foot switch, or an entire light show to accompany his playing.

Of course, adding a magnetic pickup to an acoustic guitar, or generally electrifying acoustic instruments like a drum kit for example, isn’t new. Neither is using a single-board computer as effect pedal or as an amp in your pocket. Having it all integrated into one single device on the other hand rightfully earns this guitar its Crazy Guitar Rig name.

(Thanks for the tip, [alex]!)

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Toddler Arcade Cabinet Is A Stand-Up Job

October 6, 2020 by Kristina Panos 6 Comments

A few years ago, [Mark] built an arcade cabinet into a low table. But once his new gaming buddy [Grayson] came along and started crawling, it wasn’t practical to have a low, pointy table around. Trouble is, [Mark] had already given [Grayson] his first taste with a Thomas the Tank Engine game. Since the kid was hooked, [Mark] rebuilt the table arcade into a toddler-sized arcade cabinet that they can both use.

The brain — a Raspberry Pi running RetroPie — should be familiar to most of our readers. [Mark] found the perfect crappy old monitor when they were upgrading at his office, and found some nice speakers to give it good bass. We love the details like the chrome edging, and especially the kick bar/footrest along the bottom. It can be difficult to decide how to decorate a multi-arcade cabinet, so [Mark] went the sticker bomb route with 700 of them randomly distributed and safe from toddler wear and tear under five coats of clear wood varnish.

We think this looks great, especially since [Mark] doesn’t have a workshop and cut all that MDF by hand on a jigsaw in the kitchen. Check out the happy train engineer after the break.

Maybe once [Grayson] is old enough to break tablets, [Mark] can build a gaming tab-inet out of it. Just sayin’.

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