Is Baking A Raspberry Pi The Recipe For Magic Smoke?

January 10, 2019 by Tom Nardi 35 Comments

No, Hackaday hasn’t become a baking blog. We’re just here to give you a bit of advice: if [MickMake] ever offers you one of his fresh-baked Pis, proceed with caution. While we have no doubt that there will be some interesting smells wafting out of his kitchen, these aren’t the tasty pies you’re looking for. There’s no delicious home-baked treat when that timer dings, just a handful of Raspberry Pis that have had an exceptionally hard day.

To properly explain the odd sight of some Raspberry Pis laid out on a cookie sheet, we need to take a step back. [MickMake] originally set out to see how everyone’s favorite Linux SBC would handle the harsh Australian heat, and thought that setting them up on his car’s dashboard would be a suitable torture test. But as luck would have it, a storm rolled in while he was making the video which brought temperatures down to a “cool” 30 C (86 F); basically jacket weather at the bottom of the world. So naturally, he decided to put them in his oven instead.

Placed on an insulating sheet and with a thermocouple between them to get an accurate idea of the temperature they were experiencing, an original Pi, a Pi 2, and a pair of Pi 3s were sent on the ride of their lives. In addition to monitoring them over the network, he also added a “heartbeat” LED to each Pi so he’d be able to tell at a glance if any of them had given up the ghost. As if these poor little Pis didn’t have it bad enough already, [MickMake] decided to take things a step farther and run sysbench on them while they took their trip through Hades.

The Pis are actually rated for temperatures up to 85C, and all the participants of the experiment hit that point without any issues. At 87.3 C (~190 F) the original Pi dropped off the network, but its LED was seen bravely blinking on. At 105.7 C (~222 F) it finally breathed its last, followed by the pair of Pi 3s tapping out at 112 C (233 F). The Pi 2 fought on, but it fell right at the 119 C (246 F) mark.

But what about when they cooled off? Somewhat surprisingly, [MickMake] successfully powered all four back up and was unable to find any damage to the Pis, either physically or operationally. Even the SD cards survived, and the Pis popped right back onto the network and were ready for another round of Silicon Chef. Not bad considering they were subjected to temperatures three times higher than the official limit.

Testing electronics in your home oven might seem a bit suspect, and admittedly we’d probably turn down a slice of the next few frozen pizza’s [MickMake] runs through it, but it’s not really so far removed from how proper reliability testing is performed.

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2600-Inspired Handheld Brings The Faux Woodgrain

January 3, 2019 by Lewin Day 4 Comments

The Atari 2600 is a console from a very different time, when home appliances, furniture, and even automobiles were all covered in fake vinyl woodgrain veneer. Somehow it was the in thing for a decade, and then immediately became tacky overnight. Regardless, if you want to evoke the era, that’s what you do – and that’s exactly what [Christian] did with this handheld RetroPie build.

An early concept sketch shows off [Christian]’s art skills.

The technical side of things is fairly routine in these parts – a Pi Zero runs RetroPie so you can play emulated games from the mid-90s and earlier. It’s the visual presentation that we particularly enjoy. The look of the early Atari is evoked through clever use of materials. The body is in black plastic, with blocky red buttons for controls. It’s finished with a vinyl woodgrain applique around the screen, and we think it’s a wonderful aesthetic.

The files to print your own are available on Thingiverse, and [Christian] has provided a basic guide to sourcing similar parts. It’s all common stuff, readily available on eBay or elsewhere.

We love seeing retro throwbacks like this – the tiny Macintosh Plus from the 2017 Superconference is a particular highlight.

The Very Slow Movie Player Does It With E-Ink

December 30, 2018 by Richard Baguley 18 Comments

Most displays are looking to play things faster. We’ve got movies at 60 frames per second, and gaming displays that run at 144 fps. But what about moving in the other direction? [Bryan Boyer] wanted to try this out, so he built the VSMP, or Very Slow Movie Player. It’s a neat device that plays back a movie at about 24 fph (frames per hour) on an e-ink display to demonstrate something that [Bryan] calls Slow Seeing, which, he says “helps you see yourself against the smear of time.” A traditional epic-length movie is now going to run you greater than 8,000 hours of viewing.

Artistic considerations aside, it’s an interesting device from a technical point of view. [Bryan] built it from a 7.4-inch e-ink display from Pervasive Displays. The controller is connected to a Raspberry Pi Zero, which is running a Python script to convert a frame of the movie file into a dithered file, then send it to the display. Because the Pi Zero isn’t a very fast computer, this takes some time, and thus the slow speed of the VSMP. Originally, [Bryan] had set it up to run as fast as the system could manage, which was about 25 seconds per frame, or about 2 frames per minute. He decided to slow it down a bit further to the more attractive multiple of 24 frames per hour to contrast with the 24 frames per second of the original movie. He did this by using a CRON job that kicks of the conversion script once every 2.5 minutes and increments the frame counter. All of this is topped off with a nice 3D-printed case that has a lovely interference pattern to make a rather neat and intriguing project.

Perhaps the best part of this is see a time-lapse of the VSMP — life moves quickly around it while 2001: A Space Odyssey plays at normal speed.

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This Raspberry Pi Is A Stereo Camera And So Much More

December 30, 2018 by Jenny List 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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HD Video And Telemetry Link Uses Standard WiFi Hardware

December 27, 2018 by Donald Papp 3 Comments

[GlytchTech] decided to implement his own Digital Data Link (DDL) for his drone experiments, and by using a Raspberry Pi Zero and some open-source software, he succeeded in creating a mostly self-contained system that delivers HD video and telemetry using an Android phone as a display.

USB tethered Android phone used as a display and touch interface.

The link uses standard WiFi hardware in a slightly unusual way to create a digital data link that acts more like an analog system, with a preference for delivering low latency video and a graceful drop-off when signal quality gets poor. A Raspberry Pi Zero, Alfa NEH WiFi card, external antenna, battery, and a 3D printed enclosure result in a self-contained unit. Two are needed: one for each end of the link. One unit goes on the drone and interfaces to the flight controller, and the other is for the ground station.

A companion android app allows for just about any old Android phone to serve as video feed, on-screen display of telemetry data, and touchscreen interface.

The software is DroneBridge (GitHub repository) and it implements Wifibroadcast which uses WiFi radios, but without the usual WiFi functionality. A Raspberry Pi is the usual platform, but there’s also an ESP32 port. The software is capable of even more, but so far suits [GlytchTech]’s needs just fine, and he was able to refine his original Watch_Dogs-inspired hacking drone with it.

Machine Learning On Tiny Platforms Like Raspberry Pi And Arduino

December 25, 2018 by Bryan Cockfield 25 Comments

Machine learning is starting to come online in all kinds of arenas lately, and the trend is likely to continue for the forseeable future. What was once only available for operators of supercomputers has found use among anyone with a reasonably powerful desktop computer. The downsizing isn’t stopping there, though, as Microsoft is pushing development of machine learning for embedded systems now.

The Embedded Learning Library (ELL) is a set of tools for allowing Arduinos, Raspberry Pis, and the like to take advantage of machine learning algorithms despite their small size and reduced capability. Microsoft intended this library to be useful for anyone, and has examples available for things like computer vision, audio keyword recognition, and a small handful of other implementations. The library should be expandable to any application where machine learning would be beneficial for a small embedded system, though, so it’s not limited to these example applications.

There is one small speed bump to running a machine learning algorithm on your Raspberry Pi, though. The high processor load tends to cause small SoCs to overheat. But adding a heatsink and fan is something we’ve certainly seen before. Don’t let your lack of a supercomputer keep you from exploring machine learning if you see a benefit to it, and if you need more power than just one Raspberry Pi you can always build a cluster to get your task done just a little bit faster, too.

Thanks to [Baldpower] for the tip!

Arduino And Pi Share Boardspace

December 24, 2018 by Brian McEvoy 18 Comments

A Raspberry Pi Zero (W) and Arduino are very different animals, the prior has processing power and connectivity while the latter has some analog to digital converters (ADCs) and nearly real-time reactions. You can connect them to one another with a USB cable and for many projects that will happily wed the two. Beyond that, we can interface this odd couple entirely through serial, SPI, I2C, and logic-level signaling. How? Through a device by [cburgess] that is being called an Arduino shield that supports a Pi0 (W). Maybe it is a cape which interfaces with Arduino. The distinction may be moot since each board has a familiar footprint and both of them are found here.

Depending on how they are set up and programmed, one can take control over the other, or they could happily do their own thing and just exchange a little information. This board is like a marriage counselor between a Raspberry Pi and an Arduino. It provides the level-shifting so they don’t blow each other up and libraries so they can speak nicely to one another. If you want to dig a bit deeper into this one, design files and code examples are on available.

Perhaps we’ll report on this board at the heart of a pinball machine retrofit, a vintage vending machine restoration, or maybe a working prop replica from the retro bar in Back to the Future II.