Go Ape With A Banana Macropad

May 14, 2021 by Kristina Panos 14 Comments

The super fun thing about macro pads is that they’re inherently ultra-personalized, so why not have fun with them? This appealing little keeb may have been a joke originally, but [dapperrogue] makes a valid point among a bunch of banana-related puns on the project page — the shape makes it quite the ergonomic little input device.

Inside this open-source banana is that perennial favorite for macro pads, the Arduino Pro Micro, and eight switches that are wired up directly to input pins. We’re not sure what flavor of Cherry those switches are, hopefully brown or green, but we suddenly wish Cherry made yellow switches. If you want to build your own, the STLs and code are available, and we know for a fact that other switch purveyors do in fact make yellow-stemmed switches.

Contrary to what the BOM says, we believe the sticker is mandatory because it just makes the build — we imagine there would be fewer double takes without it. Hopefully this fosters future fun keyboard builds from the community, and we can’t wait to sink our teeth into the split version!

There are a bunch of ways to make a macropad, including printing everything but the microcontroller.

Via r/mk and KBD

Realistic Mission Control Box Is A Blast For All Ages

May 13, 2021 by Kristina Panos 19 Comments

A lot of electronic busy boxes that are built for children are simply that — a mess of meaningless knobs and switches that don’t do much beyond actuating back and forth (which, let’s be honest, is still pretty fun to do). But this Mission Control Center by [gcall1979] knocks them all out of orbit. The simulation runs through a complete mission, including a 10-minute countdown with pre-flight system checks, 8.5 minutes of powered flight to get out of the atmosphere that includes another four tasks, and 90 minutes to orbit the Earth while passing through nine tracking stations across the world map.

That’s a lot time to keep anyone’s attention, but fortunately [gcall1979] included a simulation speed knob that can make everything go up to 15 times faster than real-time. This knob can be twiddled at any time, in case you want to savor the countdown but get into space faster, or you don’t have 90 minutes to watch the world map light up.

The main brain of this well-built box is an Arduino Mega, which controls everything but the launch systems’ mainframe computer — this is represented by bank of active LEDs that blink along with the voice in the sound clips and runs on an Arduino Uno and a couple of shift registers. To keep things relatively simple, [gcall1979] used an Adafruit sound board for the clips.

We love everything about this build, especially the attention to detail — the more important pre-flight tasks are given covered toggle switches, and there’s a Shuttle diagram that lights up as each of these are completed. And what Shuttle launch simulator would be complete without mushroom buttons for launch and abort? Grab your victory cigar and check out the demo video after the break.

Is your child too young to be launching the Shuttle? Here’s an equally cool busy box with toddler brains in mind.

Continue reading “Realistic Mission Control Box Is A Blast For All Ages” →

Piggy Bank Slot Machine Puts A Spin On Saving

May 12, 2021 by Kristina Panos 7 Comments

Saving money is inherently no fun until the time comes that you get to spend it on something awesome. Wouldn’t you be more likely to drop your coins into a piggy bank if there was a chance for an immediate payout that might exceed the amount you put in? We know we would. And the best part is, if you put such a piggy bank slot machine out in the open where your friends and neighbors can play with it, you’ll probably make even more money. As they say, the house always wins.

Drop a coin in the slot and it passes through a pair of wires that act as a simple switch to start the reels spinning. Inside is an Arduino Uno and a giant printed screw feeder that’s driven by a small stepper motor and a pair of printed gears. The reels have been modernized and the display is made of four individual LED matrices that appear as a single unit thanks to some smoky adhesive film.

This beautiful little machine took a solid week of 3D printing, which includes 32 hours wasted on a huge piece that failed twice. [Max 3D Design] tried rotating the model 180° in the slicer and thankfully, that solved the problem. Then it was on to countless hours of sanding, smoothing with body filler, priming, and painting to make it look fantastic.

If you want to make your own, all the files are up on Thingiverse. The code isn’t shown, but we know for a fact that Arduino slot machine code is out there already. Check out the build and demo video after the break.

As much as we like this build’s simplicity, it would be more slot machine-like if there was a handle to pull. Turns out you can print those, too.

Continue reading “Piggy Bank Slot Machine Puts A Spin On Saving” →

Leap Motion Controls Hands With No Glove

May 8, 2021 by Al Williams No comments

It isn’t uncommon to see a robot hand-controlled with a glove to mimic a user’s motion. [All Parts Combined] has a different method. Using a Leap Motion controller, he can record hand motions with no glove and then play them back to the robot hand at will. You can see the project in the video, below.

The project seems straightforward enough, but apparently, the Leap documentation isn’t the best. Since he worked it out, though, you might find the code useful.

An 8266 runs everything, although you could probably get by with less. The Leap provides more data than the hand has servos, so there was a bit of algorithm development.

We picked up a few tips about building flexible fingers using heated vinyl tubing. Never know when that’s going to come in handy — no pun intended. The cardboard construction isn’t going to be pretty, but a glove cover works well. You could probably 3D print something, too.

The Unity app will drive the hand live or can playback one of the five recorded routines. You can see how the record and playback work on the video.

This reminded us of another robot hand project, this one 3D printed. We’ve seen more traditional robot arms moving with a Leap before, too. Continue reading “Leap Motion Controls Hands With No Glove” →

Auto Strummer Can Plectrum The Whole Flat-Strumming Spectrum

May 7, 2021 by Kristina Panos 3 Comments

Playing the guitar requires speed, strength, and dexterity in both hands. Depending on your mobility level, rocking out with your axe might be impossible unless you could somehow hold down the strings and have a robot do the strumming for you.

[Jacob Stambaugh]’s Auto Strummer uses six lighted buttons to tell the hidden internal pick which string(s) to strum, which it does with the help of an Arduino Pro Mini and a stepper motor. If two or more buttons are pressed, all the strings between the outermost pair selected will be strummed. That little golden knob near the top is a pot that controls the strumming tempo.

[Jacob]’s impressive 3D-printed enclosure attaches to the guitar with a pair of spring-loaded clamps that grasp the edge of the sound hole. But don’t fret — there’s plenty of foam padding under every point that touches the soundboard.

We were worried that the enclosure would block or muffle the sound, even though it sits about an inch above the hole. But as you can hear in the video after the break, that doesn’t seem to be the case — it sounds fantastic.

Never touched a real guitar, but love to play Guitar Hero? There’s a robot for that, too.

Continue reading “Auto Strummer Can Plectrum The Whole Flat-Strumming Spectrum” →

ECG Project With All The Messy Safety Details

May 3, 2021 by Orlando Hoilett 11 Comments

We’ve seen a number of heart rate monitoring projects on Hackaday, but [Peter’s] electrocardiography (ECG) Instructable really caught out attention.

If you’ve followed Hackaday for any period of time, you’re probably already somewhat familiar with the hardware needed to record the ECG. First, you need a high input impedance instrumentation amplifier to pick up the millivolt signal from electrical leads carefully placed on the willing subject’s body. To accomplish this, he used an AD8232 single-lead ECG module (we’ve actually seen this part used to make a soundcard-based ECG). This chip has a built-in instrumentation amplifier as well as an optional secondary amplifier for additional gain and low-pass filtering. The ECG signal is riddled with noise from mains that can be partially attenuated with a simple low-pass filter. Then, [Peter] uses an Arduino Nano to sample the output of the AD8232, implement a digital notch filter for added mains noise reduction, and display the output on a 2.8″ TFT display.

Other than the circuit itself, two things about his project really caught our attention. [Peter] walks the reader through all the different safety considerations for a commercial ECG device and applies these principles to his simple DIY setup to ensure his own safety. As [Peter] put it, professional medical electronics should follow IEC 60601. It’s a pretty bulky document, but the main tenets quoted from [Peter’s] write-up are:

limiting how much current can pass through the patient
how much current can I pass through the patient?
what electrical isolation is required?
what happens if a “component” fails?
how much electromagnetic interference can I produce?
what about a defibrillator?

[Peter] mentions that his circuit itself does not fully conform to the standard (though he makes some honest attempts), but lays out a crude plan for doing so. These include using high-valued input resistors for the connections to the electrodes and also adding a few protection diodes to the electrode inputs so that the device can withstand a defibrillator. And of course, two simple strategies you always want to follow are using battery power and placing the device in a properly shielded enclosure.

[Peter] also does a great job breaking down the electrophysiology of the heart and relates it to terms maybe a bit more familiar to non-medical professionals. Understanding the human heart might be a little less intimidating if we relate the heart to a simple voltage source like a battery or maybe even a function generator. You can imagine the ions in our cells as charger carriers that generate electrical potential energy and nerve fibers as electrical wires along which electrical pulses travel through the body.

Honestly, [Peter] has a wealth of information and tools presented in his project that are sure to help you in your next build. You might also find his ECG simulator code really handy and his low-memory display driver code helpful as well. Cool project, [Peter]!

Measuring ECG is something that is near and dear to my heart (sorry, couldn’t resist). Two of my own projects that were featured on Hackaday before I became a writer here include a biomedical sensor suite in Arduino shield form factor, and a simple ECG built around an AD623 instrumentation amplifier.

An Arduino With A Floppy Drive

April 30, 2021 by Jenny List 30 Comments

For many of us the passing of the floppy disk is unlamented, but there remains a corps of experimenters for whom the classic removable storage format still holds some fascination. The interface for a floppy drive might have required some complexity back in the days of 8-bit microcomputers, but even for today’s less accomplished microcontrollers it’s a surprisingly straightforward hardware prospect. [David Hansel] shows us this in style, with a floppy interface, software library, and even a rudimentary DOS, for the humble Arduino Uno.

The library provides functions to allow low level work with floppy disks, to read them sector by sector. In addition it incorporates the FatFS library for MS-DOS FAT file-level access, and finally the ArduDOS environment which allows browsing of files on a floppy. The pictures show a 3.5″ drive, but it also supports 5.25″ units and both DD and HD drives. We can see that it will be extremely useful to anyone working with retrocomputer software who is trying to retrieve old disks, and we look forward to seeing it incorporated in some retrocomputer projects.

Of course, Arduino owners needn’t have all the fun when it comes to floppy disks, the Raspberry Pi gets a look-in too.