If you were a youth in the 90s, odds are good that you were a part of the virtual pet fad and had your very own beeping Tamagotchi to take care of, much to the chagrin of your parents. Without the appropriate amout of attention each day, the pets could become sick or die, and the only way to prevent this was to sneak the toy into class and hope it didn’t make too much noise. A more responsible solution to this problem would have been to build something to take care of your virtual pet for you.
An art installation in Moscow is using an Arduino to take care of five Tamagotchis simultaneously in a virtal farm of sorts. The system is directly wired to all five toys to simulate button presses, and behaves ideally to make sure all the digital animals are properly cared for. Although no source code is provided, it seems to have some sort of machine learning capability in order to best care for all five pets at the same time. The system also prints out the statuses on a thermal printer, so you can check up on the history of all of the animals.
The popularity of these toys leads to a lot of in-depth investigation of what really goes on inside them, and a lot of other modifications to the original units and to the software. You can get a complete ROM dump of one, build a giant one, or even take care of an infinite number of them. Who would have thought a passing fad would have so much hackability?
A computer is, at its core, just a bunch of transistors wired together. Once you have enough transistors on a board, though, one of the first layers of abstraction that arises is the Arithmetic Logic Unit. The ALU takes in two sets of data, performs a chosen math function, and outputs one data set as the result. It really is the core of what makes computers compute.
An ALU is built into modern processors, but that wasn’t always how it was done. If you’re looking to build a recreation of an early computer you may need a standalone, and that’s why [roelh] designed an ALU that fits in a square inch piece of circuit board using five multiplexer chips and two XOR chips.
One of the commonly used components for this purpose, the 74LS181 ALU, is not in production anymore. [roelh’s] ALU is intended to be a small footprint replacement of sorts, and can perform seven functions: ADD, SUB, XOR, XNOR, AND, OR, A, B, and NOT A. The small footprint for the design is a constraint of our recent contest: Return of the Square Inch Project. Of course, this meant extra design challenges, such as needing to move the carry in and carry out lines to a separate header because there wasn’t enough space on one edge.
Exploring the theory behind an ALU isn’t just for people building retrocomputers. It is integral to gaining an intuitive understanding of how all computers work. Everyone should consider looking under the hood by walking through the nand2tetris course which uses simulation to build from a NAND gate all the way up to a functioning computer based on The Elements of Computing Science textbook.
If you’re a homebrew computer builder, it might be worthwhile to use one of these ALUs rather than designing your own. Of course, if building components from scratch is your thing we definitely understand that motivation as well.
We all know the drill when buying a digital oscilloscope: buy the most hackable model. Some choose to void the warranty right away and access features for which the manufacturer has kindly provided all the hardware and software but has disabled through licensing. Few of us choose to tap into the underlying embedded OS, though, which seems a shame.
When [Jason Gin]’s scope started giving him hints about its true nature, he decided to find a way in. The result? An oscilloscope with a Windows desktop that plays Doom. The instrument is a Keysight DSOX1102G which [Jason] won during the company’s “Scope Month” giveaway. Relatively rare system crashes showed the familiar UI trappings of Windows CE.
Try as he might, [Jason] couldn’t get the scope to crash on cue — at least not until he tried leaving an external floppy drive plugged into the USB port on startup. But in order to use the desktop thus revealed, a keyboard and mouse were needed too. So he whipped up a custom USB switch cable, to rapidly toggle in the keyboard and mouse after the crash. This gave him the keys to the kingdom, but he still had a long way to go. We won’t spoil the story, but suffice it to say that it took [Jason] a year and a half, and he learned a lot along the way.
It was nice to hear that our review of the 1000X series scopes helped [Jason] accomplish this exploit. This hack’s great for bragging rights, as one way to prove you’ve owned a system is telling people it runs Doom!
The patience and precision involved with drawing geometric patterns in sand is right up a robot’s alley, and demonstrating this is [rob dobson]’s SandBot, a robot that draws patterns thanks to an arm with a magnetically coupled ball.
SandBot, SCARA version. The device sits underneath a sand bed, and a magnet (seen at the very top at the end of the folded “arm”) moves a ball bearing through sand.
SandBot is not a cartesian XY design. An XY frame would need to be at least as big as the sand table itself, but a SCARA arm can be much more compact. Sandbot also makes heavy use of 3D printing and laser-cut acrylic pieces, with no need of an external frame.
[rob]’s writeup is chock full of excellent detail and illustrations, and makes an excellent read. His previous SandBot design is also worth checking out, as it contains all kinds of practical details like what size of ball bearing is best for drawing in fine sand (between 15 and 20 mm diameter, it turns out. Too small and motion is jerky as the ball catches on sand grains, and too large and there is noticeable lag in movement.) Design files for the SCARA SandBot are on GitHub but [rob] has handy links to everything in his writeup for easy reference.
Sand and robots (or any moving parts) aren’t exactly a natural combination, but that hasn’t stopped anyone. We’ve seen Clearwalker stride along the beach, and the Sand Drawing Robot lowers an appendage to carve out messages in the sand while rolling along.
It has never been easier to put a microcontroller and other electronics into a simple project, and that has tremendous learning potential. But when it comes to mechanical build elements like enclosures, frames, and connectors, things haven’t quite kept the same pace. It’s easier to source economical servos, motors, and microcontroller boards than it is to arrange for other robot parts that allow for cheap and accessible customization and experimentation.
That’s where [Andy Forest] comes in with the Laser Cut Cardboard Robot Construction Kit, which started at STEAMLabs, a non-profit community makerspace in Toronto. The design makes modular frames, enclosures, and basic hardware out of laser-cut corrugated cardboard. It’s an economical and effective method of creating the mechanical elements needed for creating robots and animatronics while still allowing easy customizing. The sheets have punch-out sections for plastic straws, chopstick axles, SG90 servo motors, and of course, anything that’s missing can be easily added with hot glue or cut out with a knife. In addition to the designs being open sourced, there is also an activity guide for educators that gives visual examples of different ways to use everything.
Cardboard makes a great prototyping material, but what makes the whole project sing is the way the designs allow for easy modification and play while being easy to source and produce.
When a project has outgrown using a small microcontroller, almost everyone reaches for a single-board computer — with the Raspberry Pi being the poster child. But doing so leaves you stuck with essentially a headless Linux server: a brain in a jar when what you want is a Swiss Army knife.
It would be a lot more fun if it had a screen attached, and of course the market is filled with options on that front. Then there’s the issue of designing a human interface: touch screens are all the rage these days, so why not buy a screen with a touch interface too? Audio in and out would be great, as would other random peripherals like accelerometers, WiFi, and maybe even a cellular radio when out of WiFi range. Maybe Bluetooth? Oh heck, let’s throw in a video camera and high-powered LED just for fun. Sounds like a Raspberry Pi killer!
And this development platform should be cheap, or better yet, free. Free like any one of the old cell phones that sit piled up in my “hack me” box in the closet, instead of getting put to work in projects. While I cobble together projects out of Pi Zeros and lame TFT LCD screens, the advanced functionality of these phones sits gathering dust. And I’m not alone.
Why is this? Why don’t we see a lot more projects based around the use of old cellphones? They’re abundant, cheap, feature-rich, and powerful. For me, there’s two giant hurdles to overcome: the hardware and the software. I’m going to run down what I see as the problems with using cell phones as hacker tools, but I’d love to be proven wrong. Hence the “Ask Hackaday”: why don’t we see more projects that re-use smartphones?
It is mind-boggling when you think about the computing power that fits in the palm of your hand these days. It wasn’t long ago when air-conditioned rooms with raised floors hosted computers far less powerful that filled the whole area. Miniaturization is certainly the order of the day. Things are getting smaller every day, too. We were so impressed with the minuscule entries from the first “Square Inch Project” — a contest challenging designers to use 1 inch2 of PCB or less — that we decided bring it back with the Return of the Square Inch Project. The rules really were simple: build something with a PCB that was a square inch.
Grand Prize
It was hard to pick, but there can only be one grand prize winner. This time around that honor goes to [Danny FR] for a very small smart motor driver for robotics. The little board takes an I2C link to a microcontroller and does PID control with RPM feedback. No need for an H-bridge or any sophisticated control electronics — that’s all onboard.
The board is a great fit for a motor and makes it easy to build moving projects. That was the grand prize, but there were some other great entries that won in specific categories, too.
Best Project
[Drix] likes to know where things are. The Hive Tracker uses laser “lighthouses” that sweep across the room. A special microcontroller with a dedicated hardware block reads the laser light and triangulates its position relative to the lighthouses with a great deal of precision. A picture’s worth a thousand words, so:
The high-speed reading of the lasers uses “Programmable Peripheral Interconnect” — a feature of a Nordic BLE microcontroller that lets the chip read timestamps in hardware without interrupting the processor. The little boards hook up to a hub board which is also pretty small.
We’re hackers, so we think a few bare PCBs connected to another PCB can be artistic. But most people have something different in mind.
Best Artistic Project
If you hang out at Hackaday.io much, you’ll recognize [ꝺeshipu] and his entry was one of those things that you immediately know you could use, but also brings a little smile to your face when you use it. How often do you need to plug some LEDs into a breadboard? Why not do it with a Rainbow Jellyfish?
The circuit operation should be obvious. We really liked the color-coded wiring. You could probably use at least two of these so they could keep each other company. You could probably even use this as part of a badge.
Best Social Media Award
Speaking of badges, [nwmaker] built a badge that looks like another animal — an owl called PurpleSnowy. Again, the circuit is simple enough, but what caught our eye on this project was how well the social media promotion of it was. Maybe cute owls are just easier to go viral, but we liked it.
Best Documentation
[Kris Winer] (remember that name), built a very high-tech spectrometer project. Not only was it small in size, but at $25 it was also small in price. The project used the AMS AS7265X 3-chip set to provide an 18 channel, 20 nm FWHM spectrometer. The documentation was very well done and we were impressed with the fitment of the chips on the board.
Many Runners-Up
We had so many great entries that it was hard to pick so we named several runners-up.
[Greg Davill’s] Bosun frame grabber that uses an FPGA to capture images from a FLIR Boson camera.
[Kris Winer’s] high-tech $25 spectrometer project (from above) was also runner-up, and [Kris] was also recognized for sensors that can smell and hear.
If you want something less science-related, the Rotovis-Mod1 by [zakqwy] makes it easier to build persistence of vision displays. Of course, as hackers, we love an oscilloscope and [Mark Omo’s] 20 msps scope that fits in one inch caught our imagination for making some really cool instrument panels.
You really should look at all the entries — they were amazing. [Kris] really went all out, taking two runner up slots and the best documentation prize.
Recap:
Speaking of prizes, The grand prize was $500, and the other prizes received $100 Tindie gift certificates. Thanks to OSH Park, the runner ups also got $100 OSH Park gift cards — that’s a lot of one inch PCBs.
Will this be our last inch square contest? The magic 8 ball says probably not, so don’t stop thinking small and look for your chance to enter your design in the next contest.
That’s where [Andy Forest] comes in with the 
