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There have been plenty of Z80 computer builds here on Hackaday, but what sets them apart is what you do with them. [Andrew] writes in with his Z80 single-board computer made from scratch, using the Arduino standard headers for its I/O. In turn, since he needed an easy way to program the flash memory which holds the software to run on the Z80, he used an Arduino Mega as a debugger, making the SBC an Arduino shield itself.

Using such a common header pinout for the Z80 computer allows it to be used with a variety of readily-available Arduino shields. This compatibility is achieved with an analog-digital converter and a 3.3 V regulator, mimicking the pins found in an Arduino Uno. The code, available on GitHub, includes an extensive explanation and walkthrough over the process in which the Mega takes over the bus from the Z80 to function as a fully-featured debugger. Programs can be loaded through embedding an assembly listing into the Mega’s sketch, or, once the debugger is up you can also upload a compiled hex file through the serial connection.

This isn’t the first time [Andrew] has been featured here, and his past projects are just as interesting. If you need to translate a Soviet-era calculator’s buttons into English, hack a metallurgical microscope or even investigate what’s that Clacking Clanking Scraping Sound, he’s the one you should call.

[Gurpreet] fell in love with the peaceful, floaty theme from the Avatar series and bought a kalimba so he could hear it resonate through his fingertips. He soon realized that although it’s nice to play the kalimba, it would be a lot cooler if it played itself. Then he could relax and enjoy the music without wearing out his thumbs.

After doing a bit of experimentation with printing tine-plucking extensions for the servo horns, [Gurpreet] decided to start the design process by mounting the servos on a printed base. The servos are slotted into place by their mounting tabs and secured with hot glue. We think this was a good choice — it’s functional and it looks cool, like a heat sink.

[Gurpreet]’s future plans include more servos to pluck the rest of the tines, and figuring out how feed it MIDI and play it real time. For the demo after the break, [Gurpreet] says he lapel mic’d the kalimba from the back and cut out the servo noise with Audacity, but ultimately wants to figure out how to quiet them directly. He’s going to try lubing the gears and making a sound-dampening enclosure with foam, but if you have any other ideas, let him know down below.

We don’t see too many kalimba projects around here, but here’s one connected to a Teensy-based looper.

Via [r/arduino]

We would love to be a fly on the wall Christmas morning to see [Wilksyonreddit]’s kid tear the paper off of this adult-level busy box. Can you imagine the unbridled glee? It should certainly make the arduous six-month build worth the trouble. Here’s hoping the walls are sturdy, because we predict they will be bounced off of.

This gift that keeps on giving has an Arduino MEGA clone inside and a couple of shift registers to deal with all those buttons and switches. In addition to all the buttons, switches, and the number pad, there are two 3D-printed touch sensor pads that can detect little fingers up to four inches away. Although he’s already built a few games and activities for it, [Wilksy] posted this in r/duino looking for more ideas. There’s a lot to work with here on baby’s first nuclear missile launch console, both input- and output-wise. We humbly suggest 4D Simon, though we must admit to fantasizing about MIDI controllers.

Hidden inside this Christmas present is an Easter egg we think you’ll appreciate. Enter the right code, and the box becomes a treasure trove of Back to the Future sound effects and audio clips. Video’s after the break, McFly.

This box would make a great Kerbal Space Program controller, too, like this one.

 

 

Time is probably our most important social construct. Our perception of passing time changes with everything we do, and when it comes down to it, time is all we really have. You can choose to use it wisely, or sit back and watch it go by. If you want to do both, build a clock like this one, and spectate in sleek, sophisticated style.

[ChristineNZ]’s mid-century-meets-steampunk clock uses eight ILC1-1/8Ls, which are quite possibly the largest VFD tubes ever produced (and still available as new-old stock). In addition to the time, it displays the date, relative humidity, and temperature in both Celsius and Fahrenheit. A delightful chime sounds every fifteen minutes to remind you that time’s a-wastin’.

The seconds slip by in HH/MM/SS format, each division separated by a tube dedicated to dancing the time away. The mesmerizing display is driven by an Arduino Mega and a MAX6921 VFD driver, and built into a mahogany frame. There isn’t a single PCB in sight except for the Mega — all the VFDs are mounted on wood and everything is wired point-to-point. Sweep past the break to see the progressive slideshow build video that ends with a demo of all the functions.

Those glowing blue-green displays aren’t limited to clocking time. They can replace LCDs, or be scrolling marquees.

It’s fair to say that building electronic gadgets is easier now than it ever has been in the past. With low-cost modular components, there’s often just a couple dozen lines of code and a few jumper wires standing between your idea and a functioning prototype. Driving stepper motors is a perfect example: you can grab a cheap controller board, hook it up to a microcontroller, and the rest is essentially just software. But recently [mechatronicsguy] wondered if even that was more hardware than was technically necessary to get the job done.

It’s not that he was intentionally looking to make things more complicated for himself, of course. His rationale was entirely economic; if you’re looking to drive a dozen or more stepper motors, even the “cheap” controllers can add up. So he started to wonder if he could skip the controller entirely and connect the stepper motor directly to the digital pins of an Arduino. Generally speaking this is a bad idea, but if you’re careful and are willing to take the risk, [mechatronicsguy] is living proof it’s possible

So what’s the trick to running a whopping seventeen individual stepper motors directly from the digital pins of an Arduino Mega? Well, to start with you’re not going to be running the beefy NEMA 17 motors like you might find in a 3D printer. [mechatronicsguy] is using the diminutive (and dirt cheap) 28BYJ-48, a light duty stepper used in many consumer products. Even with this relatively tiny motor, you need to crack open the case and cut a trace on the PCB to switch it from unipolar to bipolar.

Beyond that, you need to be careful. [mechatronicsguy] reports he’s had success running as many as ten of them at once, but realistically the fewer operating simultaneously the better. This is actually made easier due to the relatively poor specs of the 28BYJ-48 motor; its huge eleven degree step size means its not really susceptible to the same kind of slippage you’d get on a NEMA 17 when powered down. This means you can cut power to all but the actively moving motor and be fairly sure they’ll all stay where you left them.

With as popular as the 28BYJ-48 stepper is, there are several projects this “quick and dirty” method of interfacing could potentially work with. This small “barn door” star tracker is an obvious example, but we’ve also seen some very nice robotic arms built with these low-cost motors which could benefit from the technique.

If you have a small logistics problem, we have the solution for you. [Leon] built a tiny little forklift with LED lighting, working forks, and remote control using a combination of 3D printing tech, some CNC work, and fine soldering skills.

The electronics for this build are based around a few servos and a pair of geared DC motors and are driven via an Arduino Mega. Connectivity and remote controllability are what you would expect from an Arduinified project. There’s an HC-05 Bluetooth module on the board and remote control is handled by a custom Android app.

Of note in this project are the forks that actually work, almost like a real forklift. This allows the mini Arduino forklift to pick up mini pallets, drop them somewhere, and have mini DIY enthusiasts come up to build mini-furniture for mini-Etsy, which will be prominently featured in the mini foyer of a mini two-story walkup. No, it’s not mini-gentrification; this mini forklift is helping the mini local economy.

You can check out the entire build video below, filmed in the usual maker demo method of speeding up the entire build process but somehow keeping the no-talking audio. We have a lot to thank [Jimmy DiResta] for, and it’s not just cinematography. All the files for this forklift are up on the Github should you want to build your own.

The Arduino Mega is a useful tool for the maker. Generally, once one has come up with plans for blinking LEDs that require more IO than is available on the Arduino Uno, one graduates to the Mega and goes for broke. However, it’s not typically what we’d consider as our first choice for video work. [Stephane] begs to differ, and coded this Bad Apple!! demo for the Arduino Mega 2560.

For those unfamiliar, video on the Arduino is actually somewhat of a solved problem – merely requiring a pair of resistors and some nifty code. The real meat of this hack is the video storage itself. It’s been done before, but by streaming data off an SD card or serial link. [Stephane] was determined to store everything on the Arduino itself, and thus the hack begun. Video data is stored as 1 bit per pixel, as it’s a simple black and white video as per the original inspiration. LZ77 compression was used to cram the data down without requiring too much RAM, which is a limited resource on the Mega. It’s video only, as the Mega is tapped out handling 3 minutes and 39 seconds of video storage, but future work may include syncing with a second Arduino to deliver the soundtrack.

It’s a hack that shows off [Stephane]’s ability to get impressive performance out of limited platforms. We’ve seen this before, with his excellent Star Fox port to the Arduboy. Video after the break.

The Arduino Mega is a useful tool for the maker. Generally, once one has come up with plans for blinking LEDs that require more IO than is available on the Arduino Uno, one graduates to the Mega and goes for broke. However, it’s not typically what we’d consider as our first choice for video work. [Stephane] begs to differ, and coded this Bad Apple!! demo for the Arduino Mega 2560.

For those unfamiliar, video on the Arduino is actually somewhat of a solved problem – merely requiring a pair of resistors and some nifty code. The real meat of this hack is the video storage itself. It’s been done before, but by streaming data off an SD card or serial link. [Stephane] was determined to store everything on the Arduino itself, and thus the hack begun. Video data is stored as 1 bit per pixel, as it’s a simple black and white video as per the original inspiration. LZ77 compression was used to cram the data down without requiring too much RAM, which is a limited resource on the Mega. It’s video only, as the Mega is tapped out handling 3 minutes and 39 seconds of video storage, but future work may include syncing with a second Arduino to deliver the soundtrack.

It’s a hack that shows off [Stephane]’s ability to get impressive performance out of limited platforms. We’ve seen this before, with his excellent Star Fox port to the Arduboy. Video after the break.

Split-flap displays show information using characters changed by an electric motor. While they’ve largely been replaced by more modern means, hobbyists like “gabbapeople” have been keeping this this technique alive, in this case as a four-character weather display.

The device is built using laser-cut plexiglass, and uses four individual servos to actuate the character flaps. Control is accomplished using an Arduino Mega programmed in the XOD visual programming environment, along with the requisite driver modules. Weather data is pulled from the AccuWeather API. 

You can see it flapping away in the video below, displaying the weather in abbreviations such as “ICLO” for intermittent clouds, as well as the temperature in degrees Celsius.

After Instructables user R0RSHACH’s son won a place at the World Scout Jamboree in 2019, the maker decided to create a fairground-style game for fundraising. 

The resulting device is akin to a Whack-a-Mole or Batak game that can be found at high-end gyms, and features eight large light-up buttons per player on a wooden frame.

When activated, an Arduino Mega turns on the button-lights in sequence to test how long it takes participants to push each one. While it can be made in a single-player version, the two-player game looks like a lot more fun, allowing participants to compete on opposing boards. 

Code and instructions are available here, and you can see it demonstrated in the videos below.



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