Laptop With Raspberry Pi Inside Learns To Speak Battery

December 30, 2017 by Mike Szczys 6 Comments

Early in November we took a look at a one of the best Raspberry Pi laptops we had ever seen, using the shell of a Sony VAIO. Laptops used to be hulking beasts, and that played into [Frank Adams’] hands as he got rid of the motherboard and had enough space to replace it with a Raspberry Pi and a few other support boards. This took advantage of the laptop’s screen, keyboard, LEDs, etc. But what’s a laptop without battery power? [Frank] hadn’t cracked that nut until now.

Inside of Sony VAIO laptop turned Raspberry Pi computer — VAIO battery and charging PCB seen to lower left

Adding battery power is trickier that it sounds, but [Frank] managed to get the Raspberry Pi to talk to the original Sony VAIO internal battery. His work on the project is shared, but this part of the story is best found starting on page 29 of his PDF project details.

Using the original battery is a good move since it’s designed to fit and has a charger ready to interface with the port on the laptop case. But these batteries have logic inside them, and there’s the rub. Communications use the 2-wire System Management Bus (SMBus) which is well documented. But the when trying to use the Pi’s I2C [Frank] couldn’t figure out to send a repeated start command.

He ended up writing his own C program that bit-bangs the communications he needed and now has the Pi speaking to the battery and listening to what it hears coming back. Reading through his description of this is fun since he includes his observations from a logic analyzer captures. He suspects an occasional bad read is due to Linux interrupting code execution. He watches for and catches these bad reads in software and can now reliably read all the battery vitals.

The hack leaves him with a system that functions in much the same way the original computer did: plug it in and it charges. He did add some hardware that lets him take a voltage reading from the battery using an ADC on the Teensy that was already present to control the keyboard and case LEDs. This adds a small constant draw on the battery, but for now he doesn’t leave the battery connected when the laptop is not in use.

If you’d like to read our original coverage of this laptop, here it is.

Fast 3D Printing With Raspberry Pi — But Not How You Think

December 26, 2017 by Al Williams 117 Comments

Although we tend to think of 3D printers as high-tech toys, most of them are not especially powerful in the brain department. There are some exceptions, but most 3D printers run on either an 8-bit Arduino or some Arduino variant with a lot of I/O. There are a few 32-bit boards, but if you grab a random 3D printer, its brain is going to be an 8-bit AVR running something like Marlin or Repetier. It isn’t uncommon to see a Raspberry Pi connected to a printer, too, but — again, in general — it is a network interface that handles sending G-code to the 8-bit controller that runs the stepper motors. Would it make more sense to do things like parse G-code, map out curves, and set accelerations in the relatively powerful Raspberry Pi and relegate the 8-bit AVR to just commanding motors and heaters? [KevinOConnor] thinks so, and he wrote Klipper to prove it.

Klipper is mostly written in Python and it does most of the functions of traditional 3D printing firmware. It communicates with the onboard microprocessor by providing a schedule of when to do what tasks. The microprocessor then handles the timing and things like motion control for the axes and extruder. Klipper can control multiple microprocessors with no trouble and keeps them in synchronization, so you could have a processor for your extruder and one for each stepper, for example. You can use Klipper with a Cartesian machine, a delta, or a Core XY-style printer.

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A Laser Cut Arcade Cabinet For Ants

December 25, 2017 by Tom Nardi 2 Comments

Most of us would probably like to have an arcade cabinet at home, but it’s hard to justify the space they take up. Sure it’s an awesome conversation starter when friends are over, and you might even play it regularly, but at some point you’ll look over at the corner and realize there’s probably something more practical you could be doing with that particular section of the room.

Perhaps the solution is to just make a smaller one. You could do one at half scale, or even desktop sized. But why stop there? Why not make one so small that you could put the thing in a drawer when you don’t need it? While it might be more of an academic experiment than a practical entertainment device, [RedPixel] has managed to create just such an easily concealable arcade cabinet out of a Pi Zero and laser cut wood. At only 83 mm high, this may well be the smallest functional arcade cabinet ever made (at least for now).

All of the cabinet parts were drawn in Inkscape and cut out of 3 mm plywood. The buttons and joystick are wired directly to the Pi Zero’s GPIO pins and configured with Adafruit-retrogame. The display is a SPI ILI9163, which [RedPixel] previously documented on his site.

The Pi is running the ever-popular RetroPie, which allows this tiny arcade cabinet to emulate 1000’s of console and arcade games, assuming you can deal with the controls anyway. While [RedPixel] has uploaded a video of his lilliputian cabinet running an emulator, there’s no video of him actually playing the thing. While we don’t doubt that it functions as advertised, gameplay on such a tiny array of inputs must be very difficult.

This may be the smallest functional arcade cabinet to date, but it isn’t without challengers. We’ve covered a number of very impressive builds that manage to invoke the look and feel of a hulking coin-up despite fitting neatly on your desk.

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Bringing A Christmas Lights Show Inside

December 21, 2017 by James Hobson 15 Comments

Instructables user [Osprey22] has been building towards this Christmas for years. Why? This year, he has brought an impressive musical Christmas light display inside, and at a fraction of the cost too!

An box at the tree’s base hides the power supply and the controller boards — a Raspberry Pi and a SanDevices e682 Pixel controller for the 400 WS2811 RGB LEDs — with an added router to connect them to the main network. The Pi is running Falcon Pi Player and a projector somewhere in the region of $100 complements the light show.

As far as mapping out the LEDs, Xlights is the program of choice, locating the LEDs in space with the help of a cell phone video recording. [Osprey22] had to write a quick program in C to fix the LED overlaps in the grid. (A spreadsheet would work just as well, here). Oh, and the gifts at the bottom of the tree double as a projector screen!

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A Gloriously Impractical Electromechanical Display

December 19, 2017 by Tom Nardi 28 Comments

For this year’s office holiday party, [Gavan Fantom] wanted to do something really special. Coworkers were messing with LEDs to come up with displays and decorations, but they lack that old-school feel of mechanical displays. He wanted to create something that had retro look of moving elements, but didn’t want to just recreate the traditional flip mechanism we’ve all seen over and over.

The mechanism to drive a single “pixel”.

What [Gavan] came up with is breathtakingly impractical 8×8 display that sounds as cool as it looks. Each “pixel” in the display is a 3D printed screw mechanism rotated by a hobby servo. As the pixel is rotated in its case, it becomes progressively more visible to the observer. The opacity of the pixel can even be adjusted by varying the degree of rotation, allowing for rudimentary display of grayscale images.

Each element in the display is made up of seven 3D printed parts and two nails, which the mechanism slides on to move forward and backward. An 8×8 display needs 64 elements, which means the entire display needs 64 servos, 128 nails, and a whopping 448 3D-printed parts. Even with two printers attacking the production in parallel, the printing alone took over two weeks to complete.

The display is powered by a Raspberry Pi and three “Mini Maestro” controllers which can each handle 24 servos. [Gavan] found some sample code in Python to pass commands to the Maestro servo controllers, which he used as a template when writing his own software. The Python script opens image files, converts them to grayscale, and then maps the value of each pixel to rotation of the corresponding servo. He says the software is a little rough and that there’s still some calibration to be done, but we think the results are phenomenal so far.

Mechanical displays are a favorite of hackers, due in no small part to the awesome noises they make while in operation. While we’ve seen some very creative approaches to this type of display before, what [Gavan] has created here is certainly in a league of its own.

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Google’s AIY Vision Kit Augments Pi With Vision Processor

December 17, 2017 by Steven Dufresne 29 Comments

Google has announced their soon to be available Vision Kit, their next easy to assemble Artificial Intelligence Yourself (AIY) product. You’ll have to provide your own Raspberry Pi Zero W but that’s okay since what makes this special is Google’s VisionBonnet board that they do provide, basically a low power neural network accelerator board running TensorFlow.

AIY VisionBonnet with Myriad 2 (MA2450) chip

The VisionBonnet is built around the Intel® Movidius™ Myriad 2 (aka MA2450) vision processing unit (VPU) chip. See the video below for an overview of this chip, but what it allows is the rapid processing of compute-intensive neural networks. We don’t think you’d use it for training the neural nets, just for doing the inference, or in human terms, for making use of the trained neural nets. It may be worth getting the kit for this board alone to use in your own hacks. An alternative is to get Modivius’s Neural Compute Stick, which has the same chip on a USB stick for around $80, not quite double the Vision Kit’s $45 price tag.

The Vision Kit isn’t out yet so we can’t be certain of the details, but based on the hardware it looks like you’ll point the camera at something, press a button and it will speak. We’ve seen this before with this talking object recognizer on a Pi 3 (full disclosure, it was made by yours truly) but without the hardware acceleration, a single object recognition took around 10 seconds. In the vision kit we expect the recognition will be in real-time. So the Vision Kit may be much more dynamic than that. And in case it wasn’t clear, a key feature is that nothing is done on the cloud here, all processing is local.

The kit comes with three different applications: an object recognition one that can recognize up to 1000 different classes of objects, another that recognizes faces and their expressions, and a third that detects people, cats, and dogs. While you can get up to a lot of mischief with just that, you can run your own neural networks too. If you need a refresher on TensorFlow then check out our introduction. And be sure to check out the Myriad 2 VPU video below the break.

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Old TV Lends Case To Retro Magic Mirror

December 12, 2017 by Dan Maloney 10 Comments

Remember the days when the television was the most important appliance in the house? On at dawn for the morning news and weather, and off when Johnny Carson said goodnight, it was the indispensable portal to the larger world. Broadcast TV may have relinquished its hold on the public mind in favor of smartphones, but an information portal built into an old TV might take you back to the old days.

It seems like [MisterM] has a little bit of a thing for the retro look. Witness the wallpaper in the video after the break for proof, as well as his Google-ized Radio Shack intercom project from a few months back. His current project should fit right in, based on an 8″ black-and-white TV from the 70s as it is. TVs were bulky back then to allow for the long neck of the CRT, so he decided to lop off the majority of the case and use just the bezel for his build. An 8″ Pimoroni display sits where the old tube once lived, and replicates the original 4:3 aspect ratio. With Chromium set up in kiosk mode, the family can quickly select from a variety of news and information “channels” using the original tuning knob, while parts from a salvaged mouse turns the volume control into a scroll wheel.

It’s a nice twist on the magic mirror concept, and a little different from the other retro-TV projects we’ve seen, like a retro gaming console or an old-time case for a smart TV.

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