Sometimes, it is interesting to see what you can build from the bits that you have in your junk drawer. [Dr West] decided to build a printer with spare parts including a hard drive, a scanner base and an Arduino. The result is a rather cool printer that prints out the image using a pencil, tapping the image out one dot at a time. The software converts the image into an array, with 0 representing white and 1 representing black. The printer itself works a bit like an old-school CRT TV: the scanner array moves the printer along a horizontal line, then moves it vertically and along another horizontal line. It then triggers the hard drive actuator to create a mark on the paper if there is a 1 in the array at that point.

We’ve seen a few drawing printers before, but most use a plotter or CNC approach, where the motors move the pencil on an X-Y . This type of dot matrix printer (sometimes called a dotter) isn’t as efficient, but it’s a lot of fun and shows what can be achieved with  a few bits of junk and a some ingenuity.

[Clare] isn’t the most musically inclined person, but she can strum a guitar. Thanks to a little help from an Arduino, she doesn’t even have to do that.

She built the strumbot, which handles the strumming hand duties of playing the guitar. While [Claire] does believe in her strumbot, she didn’t want to drill holes in her guitar, so hot glue and double-sided foam tape were the order of the day.

The business end of the strumbot is a micro servo. The servo moves two chopsticks and draws the pick across the strings. The tiny servo surprisingly does a great job getting the strings ringing. The only downside is the noise from the plastic gears when it’s really rocking out.

Strumbot’s user interface is a 3D-printed case with three buttons and three LEDs. Each button activates a different strum pattern in the Arduino’s programming. The LEDs indicate the currently active pattern. Everything is powered by a USB power pack, making this a self-contained hack.

[Clare] was able to code up some complex strum patterns, but the strumbot is still a bit limited in that it only holds three patterns. It’s good enough for her rendition of “Call Me Maybe”, which you can see in the video after the break. Sure, this is a simple project, not nearly as complex as some of the robotic guitar mods we’ve seen in the past. Still, it’s just the ticket for a fun evening or weekend project – especially if you’re introducing the Arduino to young coders. Music, hacking, and modding – what more could you ask for?

A delightful version of a clever one-dimensional game has been made by [Critters] which he calls TWANG! because the joystick is made from a spring doorstop with an accelerometer in the tip. The game itself is played out on an RGB LED strip. As a result, the game world, the player, goal, and enemies are all represented on a single line of LEDs.

How can a dungeon crawler game be represented in 1D, and how is this unusual game played? The goal is for the player (a green dot) to reach the goal (a blue dot) to advance to the next level. Making this more difficult are enemies (red dots) which move in different ways. The joystick is moved left or right to advance the player’s blue dot left or right, and the player can attack with a “twang” motion of the joystick, which eliminates nearby enemies. By playing with brightness and color, a surprising amount of gameplay can be jammed into a one-dimensional display!

Code for TWANG! is on github and models for 3D printing the physical pieces are on Thingiverse. The video (embedded below) focuses mainly on the development process, but does have the gameplay elements explained as well and demonstrates some slick animations and sharp feedback.

Using a spring doorstop as a controller is neat as heck as well as intuitive, but possibly not quite as intuitive as using an actual car as a video game controller.

If you have even the most passing interest in space and what it takes to get there, you’ve probably already played Kerbal Space Program (KSP). If you haven’t, then you should set aside about ten hours today to go check that out real quick. Don’t worry, Hackaday will still be here when you get back. Right now you need to focus on getting those rockets built and establishing a network of communication satellites so you can get out of low orbit.

For those of you who’ve played the game (or are joining us again after playing KSP for the prescribed 10, 12, 16 hours), you’ll know that the humble computer keyboard is not very well suited to jaunts through space. You really want a joystick and throttle at the absolute minimum for accurate maneuvers, but even you’ll be spending plenty of time back on the keyboard to operate the craft’s various systems. If you want the ultimate KSP control setup, you’ll need to follow in the footsteps of [Hugo Peeters] and build your own. Luckily for us, he’s written up an exceptionally well detailed guide on building KSP controllers that should prove useful even if you don’t want to clone his.

At the most basic level, building a KSP controller consists of hooking a bunch of switches and buttons to a microcontroller such as the Arduino or Teensy, and converting those to USB HID key presses that the game understands. This works fine up to a point, but is limited because it’s only a one-way method of communication. For his controller, [Hugo] forked KSPSerialIO, a plugin for KSP that allows bidirectional communication between the game and your controller, enabling things like digital readouts of speed and fuel levels on the controller’s panel.

Once the logistics of how you’ll talk to the game are settled, the rest is really up to the individual. The first step in building your own KSP controller is deciding what you want it to do. Are you looking to fly planes? Control a rover? Maybe you just want a master control panel for your space station. There’s a whole lot of things you can build in KSP, and the layout, inputs, and displays on your controller should ideally reflect your play style.

[Hugo] went with a fairly general purpose panel, but did spend quite a bit of extra time to get some slick LED bar graphs hooked up to display resource levels of different systems on his craft. That’s an extra step that isn’t strictly required for a build like this, but once you see it, you’re going to have a hard time not wanting to include it on your own panel. He also went through the expense of having the panel and case professionally laser cut and etched, which definitely gives it a polished feel.

We’ve covered quite a number of custom KSP controllers here at Hackaday. The overlap between KSP players and hackers seems unusually high, but of course a game that lets you build and fly contraptions of your own design does sound like something that would be right up our alley.

Like a lot of 16-year-olds, [Maxime Coutée] wanted an Oculus Rift. Unlike a lot of 16-year-olds, [Maxime] and friends [Gabriel] and [Jonas] built one themselves for about a hundred bucks and posted it on GitHub. We’ll admit that at 16 we weren’t throwing around words like quaternions and antiderivatives, so we were duly impressed.

Before you assume this is just a box to put a phone in like a Google Cardboard, take a look at the bill of materials: an Arduino Due, a 2K LCD screen, a Fresnel lens, and an accelerometer/gyro. The team notes that the screen is what will push the price unpredictably, but they got by for about a hundred euro. At the current exchange rate, if you add up all the parts, they went a little over $100, but they were still under $150 assuming you have a 3D printer to print the mechanical parts.

The system uses two custom libraries that you could use even if you wanted a slightly different project. FastVR creates 3D virtual reality using Unity and WRMHL allows Unity to communicate with an Arduino. Both of these are on the team’s GitHub page, as well.

There was one other member of the team, their math teacher [Jerome Dieudonne] who they call [Sensei]. According to [Jerome] he is “… the theoretician of the team. I teach them math and I help them solving algorithm issues.” He must be very proud and we always applaud when someone takes the time to share what they know with students.

We don’t know what’s next for this group, but we will be keeping an eye on them to see what’s next. Maybe they’ll work on smell-o-vision.

Macros are useful things. They allow one to execute a series of commands with a single keypress. There exists a wide variety of hardware and software solutions to create and use macros to improve your workflow, and now [Evan] has brought the open-source ManyKey into the fray, along with a build tutorial to boot.

The tutorial acts as a great introduction to ManyKey, as [Evan] walks through the construction of a macro keyboard designed to be operated by the feet. Based around the Arduino Leonardo and using off-the-shelf footswitches commonly used in guitar effects, it’s accessible while still hinting at the flexibility of the system. Macros are programmed into the keyboard through a Python app which communicates over serial, and configurations are saved into the Arduino’s onboard EEPROM. The ManyKey source is naturally available over at GitHub.

[Evan] tells us he uses his setup to run DJ software with his feet while his hands are busy on the turntables. That said, there’s all manner of other applications this could be used for. Efficiency is everything, and we love to see keyboard projects that aim to improve workflow with new ideas and custom builds – this shortcut keyboard makes a great example.

An Arduino and a data radio can make a great remote sensor node. Often in such situations, the hardware ends up installed somewhere hard to get to – be it in a light fitting, behind a wall, or secreted somewhere outdoors. Not places that you’d want to squeeze a cable repeatedly into while debugging.

[2BitOrNot2Bit] decided this simply wouldn’t do, and decided to program the Arduinos over the air instead.

Using the NRF24L01 chip with the Arduino is a popular choice to add wireless communications to a small project. By installing one of these radios on both the remote hardware and a local Arduino connected to the programming computer, it’s possible to remotely flash the Arduino without any physical contact whatsoever using Optiboot.

The writeup is comprehensive and covers both the required hardware setup for both ends of the operation as well as how to install the relevant bootloaders. If you’re already using the NRF24L01 in your projects, this could be the ideal solution to your programming woes. Perhaps you’re using a different platform though – like an Arduino on WiFi? Don’t worry – you can do OTA updates that way, too.

There are plenty of PC joysticks out there, but that didn’t stop [dizekat] from building his own. Most joysticks mechanically potentiometers or encoders to measure position. Only a few high-end models use Hall effect sensors. That’s the route [dizekat] took.

Hall effect sensors are non-contact devices which measure magnetic fields. They can be used to measure the position and orientation of a magnet. That’s exactly how [dizekat] is using a trio of sensors in his design. The core of the joystick is a universal joint from an old R/C car. The center section of the joint (called a spider) has two one millimeter thick disc magnets glued to it. The Hall sensors themselves are mounted in the universal itself. [Dizekat] used a small piece of a chopstick to hold the sensors in position while he found the zero point and glued them in. A third Hall effect sensor is used to measure a throttle stick positioned on the side of the box.

An Arduino micro reads the sensors and converts the analog signal to USB.  The Arduino Joystick Library by [Matthew Heironimus] formats the data into something a PC can understand.

While this is definitely a rough work in progress, we’re excited by how much [dizekat] has accomplished with simple hand tools and glue. You don’t need a 3D printer, laser cutter, and a CNC to pull off an awesome hack!

If you think Hall effect sensors are just for joysticks, you’d be wrong – they work as cameras for imaging magnetic fields too!

Our Coin Cell Challenge competition has turned up some amazing entries, things that we wouldn’t have thought possible from such meagre power sources. Take [Vishnu M Aiea]’s entry for instance, a device which he claims can light up as a birthday reminder every year for up to fifty years.

At its heart is a modified Arduino Nano clone that draws a measured 608 nA from a CR2450N. From the specification of the cell he has calculated the 50 year maximum figure, as well as a possible 29 years for a CR2032 and 64 years for a CR2477. He does however note that this does not take self-discharge into account, but you can probably afford a new battery in a decade or so.

The Arduino clone carefully selected for its “P” version low-power processor has had its serial bridge IC removed to achieve this power consumption, as well as a voltage regulator and some discrete components. Interestingly he notes that the ATMega168P is even more frugal than its 328 cousin, so he’s used the former chip. A selection of internal flags are set for minimal power consumption, and the internal oscillator is selected to use as low a clock speed as possible. There is an Intersil ISL1208 low power RTC chip mounted on a piece of stripboard to provide the timing, and of course an LED to provide the essential birthday alert.

When the LED lights for the big day there’s always the hope you’ll receive another coin cell, this time powering an edge-lit musical birthday card.

In a project, repetitive tasks that break the flow of development work are incredibly tiresome and even simple automation can make a world of difference. [Simon Merrett] ran into exactly this while testing different stepper motors in a strain-wave gear project. The system that drives the motor accepts G-Code, but he got fed up with the overhead needed just to make a stepper rotate for a bit on demand. His solution? A grbl man-in-the-middle jog pendant that consists of not much more than a rotary encoder and an Arduino Nano. The unit dutifully passes through any commands received from a host controller, but if the encoder knob is turned it sends custom G-Code allowing [Simon] to dial in a bit acceleration-controlled motor rotation on demand. A brief demo video is below, which gives an idea of how much easier it is to focus on the nuts-and-bolts end of hardware when some simple motor movement is just a knob twist away.

[Simon]’s jog pendant moves a single motor which is exactly what he needs to ease development of his 3D printed strain-wave gear using a timing belt, but it could be programmed with any G-Code at all. Speaking of DIY jog pendants for CNC machines, don’t forget this wireless one made from an Atari 2600 joystick that jogs a plasma cutter in X and Y, and zeroes it with a push of the button.