Spectrogram Drawing For Fun And Coding

February 26, 2021 by 17 Comments

It probably can’t have taken long after the first spectrum waterfall display was created, before somebody had a go at creating a waveform that would create an image in the waterfall. We don’t know who that pioneer was, but it’s over 20 years since Aphex Twin famously used the technique in their music, so it’s nothing new. If you fancy a go for yourself, [Gokberk Yaltirakli] has the project for you, creating waterfall images with an SDR from image files, using a bit of Python code.

The value here isn’t necessarily in creating the waterfall of Bitcoin logos that can be seen in the video he’s put on the page, instead it’s in the simple explanation of creating I and Q values for an SDR. The code is a bit slow so writes its values to a file which is output by a HackRF, but it could just as easily be used by any other capable output device such as GNU Radio and a soundcard if you too want an Aphex Twin moment. The hardware for displaying a spectrum waterfall doesn’t even have to be very complex.

Thanks [Leo] for the tip.

Arduboy Gets Even Smaller With New Nano Edition

February 5, 2021 by 10 Comments

One of the selling points of the Arduboy is how slim [Kevin Bates] was able to get the Arduino-compatible game system, which is perhaps less surprising when you realize that it originally started out as a design for an electronic business card. But compared to the recently unveiled Nano version, it might as well be the old school “brick” Game Boy.

Now to be clear, [Kevin] isn’t looking to put these into official production. Though it does sound like the bare PCBs might be going up for sale in the near future. This was simply an experiment to see how far he could shrink the core Arduboy hardware while still keeping it not only playable but also code-compatible with the full-size version. While “playable” might be a tad subjective in this case, the video after the break clearly demonstrates that it’s fully functional.

Inside the 3D printed case is the same ATmega32U4 that powers the Arduboy, a 64×32 0.49″ OLED display, and a tiny 25 mAh pouch battery. There’s even a miniature piezo speaker for the bleeps and bloops. All of the pinouts have remained the same so existing code can be moved right over, though the screen is now connected over I2C. [Kevin] has released the schematics for the board in keeping with the general open nature of the Arduboy project, though for now he’s decided to hold onto the board files until it’s clear whether or not there’s a commercial future for the Nano.

We’ve seen attempts to shrink the Arduboy down before, most notably down to the point it could fit inside of a Dreamcast Visual Memory Unit, but the Nano certainly raises (or is that lowers?) the bar considerably.

Continue reading “Arduboy Gets Even Smaller With New Nano Edition” →

Repairing 200+ Raspberry Pis For A Good Cause

January 25, 2021 by 37 Comments

If somebody told you they recently purchased over 200 Raspberry Pis, you might think they were working on some kind of large-scale clustering project. But in this case, [James Dawson] purchased the collection of broken single-board computers with the intention of repairing them so they could be sent to developing countries for use in schools. It sounds like the logistics of that are proving to be a bit tricky, but we’re happy to report he’s at least made good progress on getting the Pis back up and running.

He secured this trove of what he believes to be customer returned Raspberries or the princely sum of £61 ($83 USD). At that price, even if only a fraction ended up being repairable, you’d still come out ahead. Granted all of these appear to be the original Model B, but that’s still a phenomenal deal in our book. Assuming of course you can find some reasonable way to triage them to sort out what’s worth keeping.

To that end, [James] came up with a Bash script that allowed him to check several hardware components including the USB, Ethernet, I2C, and GPIO. With the script on an SD card and a 3.5″ TFT plugged into the Pi’s header for output, he was able to quickly go through the box to get an idea of what sort of trouble he’d gotten himself into. He was only about half way through the process when he wrote this particular blog post, but by that point, he’d found just 40 Pis which wouldn’t start at all. He suspects these might be victims of some common issue in the power circuitry that he’ll investigate at a later date.

A metal ruler made short work of bent pins.
A nasty, but repairable, problem.

The majority of Pis he checked were suffering from nothing worse than some bent GPIO pins or broken SD card slots. Some of the more abused examples had their USB ports ripped off entirely, but were otherwise fine. Another 10 had dead Ethernet, and 4 appear to have damaged traces leading to their HDMI ports. While we’re interested in hearing if [James] can get those 40 dark Pis to fire back up, so far the results are quite promising.

Donating hardware is always a tricky thing, so for now [James] says he’ll be selling the repaired Pis on eBay and donating the proceeds to the Raspberry Pi Foundation so they can continue to develop hardware that will (potentially) accomplish their goal of giving students all over the world a functional computer.

A Few Of My Favorite Things: Amateur Radio

January 21, 2021 by 50 Comments

Hackaday has among its staff a significant number of writers who also hold amateur radio licenses. We’re hardware folks at heart, so we like our radios homebrew, and we’re never happier than when we’re working at high frequencies.

Amateur radio is a multi-faceted hobby, there’s just so much that’s incredibly interesting about it. It’s a shame then that as a community we sometimes get bogged down with negativity when debating the minutia. So today let’s talk about a few of my favourite things about the hobby of amateur radio. I hope that you’ll find them interesting and entertaining, and in turn share your own favorite things in the comments below.

Continue reading “A Few Of My Favorite Things: Amateur Radio” →

Building A Pocket Sized Python Playground

January 7, 2021 by 24 Comments

Like many of us, [Ramin Assadollahi] has a certain fondness for the computers of yesteryear. Finding his itch for nearly instant boot times and bare metal programming weren’t being adequately scratched by any of his modern devices, he decided to build the PortablePy: a pocket-sized device that can drop him directly into a Python prompt wherever and whenever the urge hits him.

The device is powered by the Adafruit PyPortal Titano, which combines a ATSAMD51J20, ESP32, an array of sensors, and a 3.5″ diagonal 320 x 480 color TFT into one turn-key unit. The PyPortal is designed to run CircuitPython, but the scripts are usually dropped on the device over USB. That’s fine for most applications, but [Ramin] wanted his portable to be usable without the need for a host computer.

For a truly mobile experience, he had to figure out a way to bang out some Python code on the device itself. The answer ended up being the M5Stack CardKB, a tiny QWERTY board that communicates over I2C. Once he verified the concept was sound, he wrote a simple file management application and minimal Python editor that could run right on the PyPortal.

The final step was packaging the whole thing up into something he could actually take off the bench. He designed a 3D printed clamshell case inspired by the classic Game Boy Advance SP, making sure to leave enough room in the bottom half to pack in a charging board and LiPo pouch battery. He did have to remove some of the connectors from the back of the PyPortal to get everything to fit inside the case, but the compact final result seems worth the effort.

While an overall success, [Ramin] notes there are a few lingering issues. For one thing, the keyboard is literally a pain to type on. He’s considering building a custom keyboard with softer buttons, but it’s a long-term goal. More immediately he’s focusing on improving the software side of things so its easier to write code and manage multiple files.

It sounds like [Ramin] isn’t looking to compromise on his goal of making the PortablePy completely standalone, but if your convictions aren’t as strong, you could always connect a device like this up to your mobile to make things a bit easier.

Continue reading “Building A Pocket Sized Python Playground” →

You Got Something On Your Processor Bus: The Joys Of Hacking ISA And PCI

January 6, 2021 by 32 Comments

Although the ability to expand a home computer with more RAM, storage and other features has been around for as long as home computers exist, it wasn’t until the IBM PC that the concept of a fully open and modular computer system became mainstream. Instead of being limited to a system configuration provided by the manufacturer and a few add-ons that really didn’t integrate well, the concept of expansion cards opened up whole industries as well as a big hobbyist market.

The first IBM PC had five 8-bit expansion slots that were connected directly to the 8088 CPU. With the IBM PC/AT these expansion slots became 16-bit courtesy of the 80286 CPU it was built around. These slots  could be used for anything from graphics cards to networking, expanded memory or custom I/O. Though there was no distinct original name for this card edge interface, around the PC/AT era it got referred to as PC bus, as well as AT bus. The name Industry Standard Architecture (ISA) bus is a retronym created by PC clone makers.

With such openness came the ability to relatively easy and cheaply make your own cards for the ISA bus, and the subsequent and equally open PCI bus. To this day this openness allows for a vibrant ecosystem, whether one wishes to build a custom ISA or PCI soundcard, or add USB support to a 1981 IBM PC system.

But what does it take to get started with ISA or PCI expansion cards today? Continue reading “You Got Something On Your Processor Bus: The Joys Of Hacking ISA And PCI” →

Inputs Of Interest: DecaTxt Ultra-Portable Chording Keyboard

January 5, 2021 by 33 Comments

Now here’s a stocking stuffer of a keyboard. The DecaTxt is the size of a deck of cards, and at first glance it looks like some kind of pocket Keno machine or other gambling or gaming apparatus. But that’s just because it’s so colorful. When you only have ten keys emulating a full keyboard, there’s bound to be some serious labeling going on, as there should be.

DecaTxt demonstration from IN10DID

The DecaTxt is a Bluetooth 4.0 chording keyboard that’s meant to be used with your phone or whatever you want to pair it with. It was originally called the In10did, which stands for Input Nomenclature Ten Digit Interface Device. Catchy, no? At some point in the last ten years, this little guy went wireless and got a cooler name — the DecaTxt. Continue reading “Inputs Of Interest: DecaTxt Ultra-Portable Chording Keyboard” →