Whether with projects featured here or out in the real world, we have a tendency to focus most upon the end product. The car, solar panel, or even robot. But there’s a lot more going on behind the scenes that needs to be taken care of as well, whether it’s fuel infrastructure to keep the car running, a semiconductor manufacturer to create silicon wafers, or a control system for the robot. This project is one of the latter: a human interface device for a robot arm that is completely DIY.

While robots are often automated, some still need human input. The human input can be required all the time, or can be used to teach the robot initially how to perform a task which will then be automated. This “keyboard” of sorts built by [Ahmed] comes with a joystick, potentiometer, and four switch inputs that are all fully programmable via an Arduino Due. With that, you can perform virtually any action with whatever type of robot you need, and since it’s based on an Arduino it would also be easy to expand.

The video below and project page have all the instructions and bill of materials if you want to roll out your own. It’s a pretty straightforward project but one that might be worth checking out since we don’t often feature controllers for other things, although we do see them sometimes for controlling telescopes rather than robots.

In the video below, Brazilian maker Eduardo Zola shows us that you don’t necessarily need radio waves to pass messages between Arduino boards; instead, he’s using ultrasonics. 

Zola’s setup features TX and RX transducers desoldered from an HC-SR04 module along with a pair of Unos to transmit text short distances. An LM386 amplifier and LM393 comparator are also used for the receiver.

While the transmission can easily be interrupted by putting a hand between the TX and RX, this configuration would certainly have some useful applications. So, how does it work exactly? As Hackaday explains:

Looking through the source code for the transmitter and receiver, we can see it’s about as basic as it gets. The transmitter Arduino breaks down a given string into individual characters, and then further converts the ASCII to eight binary bits. These bits are sent out as tones, and are picked up on the receiving end. Once the receiver has collected a decent chunk of tones, it works through them and turns the binary values back into ASCII characters which get dumped over serial. It’s slow, but it’s simple.

If you’d like to try it yourself, code and a full parts list can be found on the Zola’s website.

Some of the best hacks are the ones which seem perfectly obvious in hindsight; a solution to the problem that’s so elegant, you wonder how it never occurred to you before. Of course we also love the hacks that are so complex your eyes start to water, but it’s nice to have a balance. This one, sent in by [Eduardo Zola] is definitely in the former group.

In the video after the break, [Eduardo] demonstrates his extremely simple setup for using ultrasonic transducers for one-way data communication. Powered by a pair of Arduinos and using transducers salvaged from the extremely popular HC-SR04 module, there’s a good chance a lot of readers can recreate this one on their own bench with what they’ve got lying around. In this example he’s sending strings of text from one computer to another, but with a little imagination this can be used for all sorts of projects.

For the transmitter, the ultrasonic transducer is simply tied to one of the digital pins on the Arduino. The receiver is a bit more complex, requiring a LM386 amplifier and LM393 comparator to create a clean signal for the second Arduino to read.

But how does it work? Looking through the source code for the transmitter and receiver, we can see it’s about as basic as it gets. The transmitter Arduino breaks down a given string into individual characters, and then further converts the ASCII to eight binary bits. These bits are sent out as tones, and are picked up on the receiving end. Once the receiver has collected a decent chunk of tones, it works through them and turns the binary values back into ASCII characters which get dumped over serial. It’s slow, but it’s simple.

If you’re looking for something a bit more robust, check out this guide on using GNU Radio with ultrasonics.

If you’d like to check out your pool or a lake without getting wet, this underwater ROV looks like a great solution. 

The DIY device features a sturdy PVC frame with six thrusters that allow it to move through water like a drone through the air (complete with depth and heading hold), and uses the same kind of controller configuration as its airborne cousin.

Onboard control is handled by an Arduino Mega along with an FPV camera, which transmit signals back to a base station via an Ethernet cable stuffed inside of a length of polypropylene rope. The driver can then see what the ROV sees on a small display, supplemented with data from the base station’s Arduino Uno and an onscreen display (OSD) shield.

We’ve all been there: after assessing a problem and thinking about a solution, we immediately rush to pursue the first that comes to mind, only to later find that there was a vastly simpler alternative. Thankfully, developing an obscure solution, though sometimes frustrating at the time, does tend to make a good Hackaday post. This time it was [David Wehr] and AudioSerial: a simple way of outputting raw serial data over the audio port of an Android phone. Though [David] could have easily used USB OTG for this project, many microcontrollers don’t have the USB-to-TTL capabilities of his Arduino – so this wasn’t entirely in vain.

At first, it seemed like a simple task: any respectable phone’s DAC should have a sample rate of at least 44.1kHz. [David] used Oboe, a high performance C++ library for Android audio apps, to create the required waveform. The 8-bit data chunks he sent can only make up 256 unique messages, so he pre-generated them. However, the DAC tried to be clever and do some interpolation with the signal – great for audio, not so much for digital waveforms. You can see the warped signal in blue compared to what it should be in orange. To fix this, an op-amp comparator was used to clean up the signal, as well as boosting it to the required voltage.

Prefer your Arduino connections wireless? Check out this smartphone-controlled periodic table of elements, or this wireless robotic hand.

A hat designed to reject a brain tumor (and console a beloved maker).

Read more on MAKE

The post Becky Stern Makes a Tumor-Rejecting Hat for Simone Giertz appeared first on Make: DIY Projects and Ideas for Makers.

Riding a bike can be great exercise, but unless you have access to a velodrome, when the weather turns bad, training is interrupted. There are of course training wheel setups that you can use to simulate riding indoors, but without the stimulus of actually moving, things can get boring rather quickly.

The Infinity Bike by Alexandre Doucet and Maxime Boudreau, however, aims to change this as a system of 3D-printable parts and sensors that can be applied to an existing bike/trainer.  A Hall effect sensor is used to measure rotations per minute, while a potentiometer mounted to the handlebars detects the steering direction. This information is transmitted to a computer and the Unity 3D environment using an Arduino Nano, allowing participants to ride in a pristine virtual environment rain or shine.

During the winter seasons, cold days and bad weather, cyclist enthusiasts only have a few options to exercise doing their favorite sport. We were looking for a way to make indoor training with a bike/trainer setup a bit more entertaining but most product available are either costly or just plain boring to use. This is why we started to develop Infinity Bike as an Open Source training video game. Infinity bike reads the speed and direction from your bicycle and offer a level of interactivity that cannot be easily found with bike trainers.

We take advantage of the simplicity available from Arduino microcontroller and a few 3D printed parts to secure inexpensive sensors to a bicycle mounted on a trainer. The information is relayed to a video game made with the popular game making engine, Unity.

An overview of the Infinity Bike can be found here, and a preview of the project can be seen in the video below! 

Tired of wondering what time it is at night, only to have to roll over to look at your alarm clock? If you’d like to avoid this nighttime inconvenience, then Kurt Andros has a great solution with his Arduino Mega-based Overhead Alarm Clock. 

The device consists of a nice wooden housing that gets mounted to a wall above where you sleep, and has separate displays for the alarm time and current time.

Instead of a menu system that you must navigate through to tune settings, the clock features buttons to change both current time and alarm time, as well as potentiometer knobs to modify brightness and alarm volume. The result is a simple interface that requires little thought to set up, and no snooze button since you can simply reprogram the wake-up time with a single button.

The overhead alarm clock offers the following features: 

• Time and alarm time can be read effortlessly and glare-free even in the dark; without glasses, without pressing buttons, without having to leave the right or left side position.

• The alarm clock can also be operated in the dark and with only one hand.

• The alarm clock can be used by a first-time user by looking at the control panel. Reading any operating instructions is not necessary.

• It wakes you up with a pleasant, volume adjustable sound (MP3 song).

• It also functions reliably in the event of a power failure.

• It is very accurate and independent of the reception of a radio signal, the power line frequency and the ambient temperature.

• It does not occupy space on the nightstand.

Sound like something you’d like in your bedroom? You can find Andros’ full project write-up here.

Ukuleles can be a lot of fun to play, and since cheap yet very playable versions can be had for under $50, they make a great target for hacking. And what better way to decorate an instrument by adding LEDs?

Elaine Chow did just that to her uke, adding six LEDs in the fingerboard along with another five embedded in the headstock. Each of these LEDs are controlled with an Arduino Uno, which light up to indicate the four most important chords: C, G, Am, and F. 

This can be set up to sequence through noted in a pre-defined path, and she’s working on a system that will detect when the correct finger positions are pressed, then moving on to the next note.

You may laugh off the ukulele as a toy or joke instrument, and admittedly, their starting price tag and the quality that usually comes with such a price tag doesn’t help much to get a different opinion on that. But it also makes it the perfect instrument for your next project. After all, they’re easy to handle, portable, and cheap enough to use a drill and other tools on them without too much regret. Plus, a little knowledge to play can get you far, and [Elaine] can teach you the essential, “all the pop songs use it”, four chords with her Arduino powered LED Ukulele.

As first step, [Elaine] drilled holes in her ukulele’s fingerboard to place some LEDs at all the positions required to play the four chords C, G, Am, and F. Connected to an Arduino attached to the ukulele’s back, each chord will light up its associated LEDs to indicate the finger positions required to play the chord itself. Taking the teaching part a step further, her next step is to extend each LED with a second, light sensing one, and read back if the fingers are placed at the correct position.

[Elaine] has already plans to turn the ukulele into an interactive game next. And if four chords are eventually not enough for you anymore, have a look at another LED based project teaching to play any major, minor and major seventh chord on the ukulele.