Spooky USB Baby Types Out Messages From Beyond

September 8, 2021 by Tom Nardi 3 Comments

You might think it’s a bit early for us to be running Halloween hacks, but don’t worry. While this microcontroller-equipped doll that mimics a USB keyboard to type out messages in the creepiest way possible might seem like a gag gift you’d get after attending somebody’s bone-chilling holiday bash, creator [Jonathan] actually put it together for a friend’s wedding. So not only is it an interesting piece of hacked together hardware, but it’s also a great reminder about the importance of having a wedding registry.

Even if this seems like a rather unusual wedding gift from an outsider’s perspective (for the record, pranks involving this “haunted doll” have been a running gag between them since their school days), we can’t help but be impressed with the way [Jonathan] implemented it. An ATtiny85-powered Digispark is hidden inside the doll, along with a simple USB 2.0 hub that supposedly eases some teething issues the diminutive development board has with newer USB 3.0 ports. Through the use of V-USB, this lets the baby type out messages once plugged into the recipient’s computer.

Soldering the Digispark to a cheap USB hub keeps newer computers happy.

Now he could have just stopped there, but [Jonathan] wanted this to be an interactive experience. Specifically, he wanted the baby to present the newlyweds with a personally test of sorts, and that meant taking user input. He came up with the clever user interface demonstrated in the video below, which responds to changes in the system’s “Caps Lock” state.

This platform-agnostic solution lets the user navigate the doll’s menu system by tapping a single key, although the Chromebook users out there will have to break out the Alt key to play along. It’s a neat trick for getting two-way communication going between a MCU and a computer without any client-side software, and worth filing away mentally for future non-haunted projects. It’s also worth checking out the effort [Jonathan] put into optimizing everything to fit into the chip’s paltry 6012 bytes of flash.

Incidentally, this is a good a time as any to remind readers that our Halloween Hackfest contest is live right now and taking entries until October 11th. If you’ve got any cursed bar mitzvah gifts you’ve been putting the finishing touches on, we’d love to see them.

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One Man’s Quest To Build A Baby Book With Brains

September 7, 2021 by Tom Nardi 44 Comments

Regular readers will know that Hackaday generally steers clear of active crowdfunding campaigns. But occasionally we do run across a project that’s unique enough that we feel compelled to dust off our stamp of approval. Especially if the campaign has already blasted past its funding goal, and we don’t have to feel bad about getting you fine folks excited over vaporware.

It’s with these caveats in mind that we present to you Computer Engineering for Babies, by [Chase Roberts]. The product of five years of research and development, this board book utilizes an internal microcontroller to help illustrate the functions of boolean logic operations like AND, OR, and XOR in an engaging way. Intended for toddlers but suitable for curious minds of all ages, the book has already surpassed 500% of its funding goal on Kickstarter at the time of this writing with no signs of slowing down.

The electronics as seen from the rear of the book.

Technical details are light on the Kickstarter page to keep things simple, but [Chase] was happy to talk specifics when we reached out to him. He explained that the original plan was to use discreet components, with early prototypes simply routing the button through the gates specified on the given page. This worked, but wasn’t quite as robust a solution as he’d like. So eventually the decision was made to move the book over to the low-power ATmega328PB microcontroller and leverage the MiniCore project so the books could be programmed with the Arduino IDE.

Obviously battery life was a major concern with the project, as a book that would go dead after sitting on the shelf for a couple weeks simply wouldn’t do. To that end, [Chase] says his code makes extensive use of the Arduino LowPower library. Essentially the firmware wakes up the ATmega every 15 ms to see if a button has been pressed or the page turned, and updates the LED state accordingly. If no changes have been observed after roughly two minutes, the chip will go into a deep sleep and won’t wake up again until an interrupt has been fired by the yellow button being pressed. He says there are some edge cases where this setup might misbehave, but in general, the book should be able to run for about a year on a coin cell.

[Chase] tells us the biggest problem was finding a reliable way to determine which page the book was currently turned to. In fact, he expects to keep tinkering with this aspect of the design until the books actually ship. The current solution uses five phototransistors attached to the the MCU’s ADC pins, which receive progressively more light as fewer pages are laying on top of them. The first sensor is exposed when the second page of the book is opened, so for example, if three of the sensors are seeing elevated light levels the code would assume the user is on page four.

Opening to the last page exposes all five light sensors.

The books and PCBs are being manufactured separately, since as you might expect, finding a single company that had experience with both proved difficult. [Chase] plans on doing the final assembly and programming of each copy in-house with the help of family members; given how many have already been sold this early in the campaign, we hope he’s got a lot of cousins.

So what do you do with an Arduino-compatible book when Junior gets tired of it? That’s what we’re particularly interested in finding out. [Chase] says he’s open to releasing the firmware as an open source project after the dust settles from the Kickstarter campaign, which would give owners a base to build from should they want to roll their own custom firmware. Obviously the peripheral hardware of the book is fairly limited, but nothing is stopping you from hanging some sensors on the I2C bus or hijacking the unused GPIO pins.

If you end up teaching your copy of Computer Engineering for Babies some new tricks, we’ve love to hear about it.

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How To Get Good With Wood

September 6, 2021 by Tom Nardi 6 Comments

It’s perhaps unsurprising that we don’t see much in the way of woodworking here at Hackaday; after all, this is a plastics and metal community if there ever was one. But that doesn’t mean you’ll never come across a situation where a dead tree needs to be cut or shaped to your will, so we appreciate [Eric Strebel] demonstrating some tips and best practices for working with this exceptionally versatile building material.

The first video assumes you’re a lumber neophyte, and goes over topics such as the different species of wood you’re likely to find at the hobby shop, proper sanding technique, and the differences between cutting with and against the grain. Some of the different cutting tools you can use are also covered, ranging from the humble hobby knife to the band saw. As always, [Eric] sprinkles the video with tips and tricks gained from his considerable professional experience, such as using some glue and a bit of sawdust to fill in any gaps left behind by an uneven joint.

In the second video, things start getting more advanced. [Eric] demonstrates how you can create custom laminates, and how wood can be permanently bent into arbitrary shapes with sufficient steam and clamping pressure. By combining these new techniques with the basic concepts covered in the first video, surprisingly complex shapes can be formed with minimal effort.

[Eric] previously put together a similar series of videos on working with acrylic, a material that’s arguably far more familiar to the Hackaday readership. But whatever material you use, the takeaway message from this series is clear: get the right tools, learn the techniques, and professional results are well within your reach.

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Wearable Scope Lets Your Fingers Do The Probing

September 3, 2021 by Tom Nardi 14 Comments

For frantic hacking sessions where seconds count, this forearm mounted oscilloscope with fingertip probes built by [aniketdhole] might be just what you need. Well, maybe. It’s not immediately clear why you might want to wear an oscilloscope on your arm, and sticking your fingers inside of powered up electronic devices sounds specifically like something your mother probably told you not to do, but here it is anyway.

The scope consists of an nRF5340 evaluation board in a 3D printed mount, with an SPI-connected Adafruit 2.8″ TFT display on top. With a pair of wires run from the board’s ADC and ground pins, [aniketdhole] just needed a bit of code to glue it all together and show some basic signal visualizations on the display. It’s been tested against PWM signals generated by an Arduino and some potentiometer controlled voltages, but anything much wilder than that is probably a bit too much to ask for from this rig in its current configuration.

In the future, [aniketdhole] wants to add some step-down circuity so you can probe higher voltages than the nRF5340 can handle normally, as well as a shunt to allow current measurement. Once the hardware is in place, the next order of business will be an improved touch-capable user interface that lets the user adjust settings and switch between functions.

Even if you’re not sold on the idea of an arm-mounted oscilloscope, this is still an interesting platform for general wearable experimentation. Throw enough sensors into it, and we’re sure there’s more than a few hackers who wouldn’t mind strapping one of these on.

Pi Pico Emulates ROM For Speedy Retro Hacking

September 2, 2021 by Tom Nardi 22 Comments

If you’ve ever worked on a system that loads its software from a ROM or EPROM, you know how much of a hassle it can be to make frequent changes to the code. Pulling the chip, flashing it, and sticking it back into the socket each time you change a line isn’t anyone’s idea of a good time. Which is why [Nick Bild] has come up with the PicoROM, a way to emulate a ROM chip using the Raspberry Pi Pico.

With the Pi Pico standing in for the original ROM, updating firmware takes a fraction of the time and doesn’t require you to actually disconnect any of the hardware. [Nick] had done something similar with FPGAs in the past, but the far cheaper and easier to work with Pi Pico makes this version particularly appealing. The secret to getting it to work is the overclocking potential of the Pico, which he says has been pushed to 400 MHz for this particular application.

The downside is that you can’t access the Pico’s onboard flash when the chip is running that fast. To get around that limitation, all of the code is loaded into the microcontroller’s RAM. With a healthy 264 KB of memory this isn’t really a problem when emulating 32 KB chips, but [Nick] says his method would quickly fall apart for larger ROMs.

Beyond the Pi Pico itself, [Nick] is using a trio of 74LVC245AN 8-bit logic level shifters so the chip can talk to the 5 V logic of his homebrew 6502 computer. With everything wired up on a simple breadboard, PicoROM has no trouble serving up the operating system as it hums along at 2 MHz.

Of course, a modern high-performance microcontroller isn’t strictly necessary. In the past we’ve covered devices that could emulate an EPROM using 1990s era silicon.

A Microcontroller Friendly AR Headset On The Cheap

September 2, 2021 by Tom Nardi 9 Comments

Generating the real-time images required for augmented reality (AR) goggles usually requires a fair amount of processing power, to the point that DIY efforts based around the Raspberry Pi often have trouble keeping up. But what if your AR aspirations don’t require fancy high-resolution graphics? If text and the occasional icon is enough to get the job done, then these lo-fi AR goggles from [bobricius] might be the ideal solution.

As with previous homebrew AR rigs we’ve seen, this one starts with an affordable headset designed to project the display of a smartphone onto a pair of curved optical combiners. But instead of tucking a phone into the headset, [bobricius] is using a custom PCB that holds a pair of ST7789 1.3 inch 240 x 240 IPS displays. Connected over SPI and supported by just about any microcontroller you’d care to use, tossing some textual data over your field of vision can be accomplished in just a few lines of code.

[bobricius] has actually put together a couple different versions of the PCB for this project. One uses his custom ATSAMD21E18-based “ArmaBrain” module that packs the MCU and an array of common components onto a 28 mm square board that can be easily dropped into other projects. If you’d rather roll your own solution, the second version of the board that simply holds the two displays in the appropriate position and routes the SPI lines to a convenient header should do nicely.

We’ve seen augmented reality displays using microcontrollers like the ESP32 before, but those were essentially just remote displays for a more powerful system. We like this simplified approach, as there are plenty of applications where just getting a few lines of text or some low-resolution images would be more than sufficient for the task at hand. Plus, the commercially-made headset this project is based on certainly looks better than some of the other donor goggles we’ve contemplated modifying in the past.

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Upgrade Board Adds GPIO Pins To Your Replica PDP-11

September 1, 2021 by Tom Nardi 10 Comments

Like many Hackaday readers, [Steven Stallion] has had his eyes on the replica PDP-11 created by [Oscar Vermeulen] for some time now, and this summer he finally got the opportunity to build one himself. But while most owners might be content to just watch the Raspberry Pi based faux-retro computer blink away on a shelf, he wanted to explore putting the machine to more practical use. The end result is the PiDP-11 I/O Expander, an add-on that lets the modern minicomputer interact with the world around it.

Developed after some discussion with [Oscar] himself, the Microchip MCP23016 based expander board fits neatly onto the PiDP-11 PCB, and [Steven] has made sure his installation guide meshes well with the replica’s documentation. The Pi’s I2C bus is actually broken out on the original PCB, so you just need to solder a header on and run some jumpers to where the expander is mounted. You’ll need to pull 5 V as well, and the installation guide has a few tips on convenient connection points.

Each expander board gives you 16 GPIO pins which can be accessed over I2C, including support for interrupts which has been connected to GPIO 19 on the Raspberry Pi. [Steven] notes that you should be able to stack multiples of his expander up should you need even more free pins, though some fiddling with pull-up resistors and I2C addresses will likely be necessary.

The PCBs for the expander have been released under the two clause BSD license, so you’re free to spin up your own copies however you see fit. But if you’d like to save some time, [Steven] is offering assembled boards on Tindie.

Since [Oscar] first teased it at the 2015 Hackaday Supercon, we’ve been enamored with his fantastic PDP-11 replica. We’re always glad to see when somebody has picked up one of these wonderful kits, and doubly so when they’ve figured out a way to expand it in unexpected ways.