After being inspired by an Old Spice commercial where actor Terry Crews plays music with his muscles and EMG sensors, hacker Julio David Barriga decided to do the same thing using an Arduino. 

While Crews’ setup involves an entire one-man band, Barriga’s system is greatly simplified, detecting the amplitude of the electrical signals emanating from his bicep. An Arduino Uno is then used to translate this signal into output notes on a small speaker, either as varying frequencies in the first video below, or as actual notes on the C major scale in the second.

The project write-up outlines a simple to implementation with a pre-built MyoWare sensor assembly, as well as a way to build own if you’d like to learn more about this technology.

While building a walking robot especially with less than six legs can be quite a challenge, maker “Skill Mill NYC” decided to construct a quadruped robot named DoggoBot using cardboard for its body.

Four micro high torque servos power the legs, which are able to move the robot around with the help of unpowered knee joints.

DoggoBot is controlled by an Arduino, and it takes movement commands via a computer USB-serial connection or from a Bluetooth module. 

Ever since I started programming Arduinos, I wanted to build a robot using one. I also want a dog. However, living in NYC makes it tough to take care of a dog. So after hours of watching videos of robots and dogs, I decided to put my phone down and build myself a pet!

Although what’s seen in the demonstration below is an impressive feat of “cardboard engineering,” its creator has a few more ideas for it, such as adding sensors and getting Doggo’ to turn.

In the United States, TV and radio stations have to give the opportunity of equal airtime to all candidates. In that spirit, we thought we should show you [Jayden17’s] hack that puts Google Assistant into a Teddy Ruxpin. You can see the hacked bear do its thing in the video below.

Teddy was the best-selling toy for 1985 and 1986, and is still available, so over 30 years there are a lot of these hanging around. If you never looked at how they work, the original ones were quite simple. A cassette player routed one stereo channel to a speaker and used the other channel to control servo motors to move the mouth and eyes. The cassette was eventually replaced with a digital cartridge, and newer versions of Teddy only use two motors instead of the three in the original.

[Jayden17’s] bear was an original “Worlds of Wonder” bear which means it is from the 1985-1990 time period. If you have a newer bear, you might have to work things out a little differently. These bears often have stuck motors, which can be fixed and broken cassette mechanisms. The cassette isn’t used with this project, so that’s not a problem.

The real key to the project is an Arduino that listens to the audio coming in from a smartphone or other source and drives the motors. The project just uses a cable for the phone, although we would have been tempted to put a cheap Bluetooth receiver in there. However, because of the way it is set up, you could easily do that. You could also use a Raspberry Pi or even switch to Alexa. The Arduino doesn’t know anything about the source audio.

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!