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Archive for the ‘arduino pro micro’ Category

USB-C versus USB Micro connectors are turning into one of the holy wars of our time. Rather than be left on the wrong side of the divide [Stefan S] has come up with his own USB-C version of of an Arduino Pro Micro to avoid having to always find a different cable.

Home made Arduinos come in all shapes and sizes from the conventional to the adventurous, and from the pictures it seems that this one is firmly in the former camp. The USB-C is present in connector form alone as the device is only capable of talking at the much slower speed of the ATMEGA32U4 processor, but having the newer connector should at least make cabling more accessible.

This is one of the most practical Arduino clones we’ve ever seen, but one of our other favourites is also a bit impractical.

How do you know if your 3D printer bed is levelled? Oh, don’t worry – you’ll know. Without a level bed, filament won’t stick properly to the build surface and you’ll run into all sorts of other problems. Knowing how tricky it can be to get the bed just right, [Antzy] built a tool to help.

The device, which he calls the FS-Touch, is based around an Arduino Pro Micro fitted with a force sensitive resistor. This allows the distance between the bed and nozzle to be measured based on the force read by the resistor when placed in between the two.

Using the tool is simple. First, the bed is brought roughly into alignment using the typical paper method. Then, a reading is taken from one corner of the bed, and the measurement saved for reference. The other corners can then be set to the same level, with the aid of LEDs to guide the user in which direction to turn the adjustment knobs.

Measuring force in this way has the potential of being more repeatable than the somewhat difficult paper method. It promises to ease the task for users that may be struggling to get their bed in proper shape. Of course, automated bed levelling makes things even easier again. Video after the break.

Part of [Gelstronic]’s house has a glass roof. While he enjoys the natural light and warmth, he doesn’t like getting up on a ladder to clean it every time a bird makes a deposit or the rainwater stains build up. He’s tried to make a cleaning robot in the past, but the 25% slope of the roof complicates things a bit. Now, with the addition of stepper motors and grippy tank treads, [Gelstronic] can tell this version of GRawler exactly how far to go, or to stay in one place to clean a spot that’s extra dirty.

GRawler is designed to clean on its way up the roof, and squeegee on the way back down. It’s driven by an Arduino Pro Micro and built from lightweight aluminium and many parts printed in PLA. GRawler also uses commonly-available things, which is always a bonus: the brush is the kind used to clean behind appliances, and the squeegee blade is from a truck-sized wiper. [Gelstronic] can control GRawler’s motors, the brush’s spin, and raise/lower the wiper blade over Bluetooth using an app called Joystick BT Commander. Squeak past the break to see it in action.

As far as we can tell, [Gelstronic] will still have to break out the ladder to place GRawler and move him between panels. Maybe the next version could be tethered, like Scrobby the solar panel-cleaning robot.

Most often ultrasonic transducers are used for distance measurements, and in the DIY world, usually as a way for robots to detect obstacles. But for a weekend project, [Vinod.S] took the ultrasonic transmitter and receiver from a distance-meter module and used amplitude modulation to send music ultrasonically from his laptop to a speaker, essentially transmitting and receiving silent, modulated sounds waves.

The transmitter and receiver
The transmitter and receiver

For the transmitter, he turned an Arduino Pro Micro into a USB sound card which he could plug into his laptop. That outputs both the audio signal and a 40 kHz carrier signal, implemented using the Arduino’s Timer1. Those go to a circuit board he designed which modulates the carrier with the audio signal using a single transistor and then sends the result out the ultrasonic transmitter.

He took care to transmit a clear signal by watching the modulated wave on an oscilloscope, looking for over-modulation and clipping while adjusting the values of resistors located between the transistor, a 5 V from the Arduino and the transmitter.

He designed the receiver side with equal care. Conceptually the circuit there is simple, consisting of the ultrasonic receiver, followed by a transistor amplifier for the modulated wave, then a diode for demodulation, another transistor amplifier, and lastly a class-D amplifier before going to a speaker.

Due to the low 40 kHz carrier frequency, the sound lacks the higher audio frequencies. But as a result of the effort he put into tuning the circuits, the sound is loud and clear. Check out the video below for an overview and to listen to the sound for yourself. Warning: Before there’s a storm of comments, yes the video’s shaky, but we think the quality of the hack more than makes up for it.

What else can you do with the ultrasonic transducers? You could wire a bunch of them to a Raspberry Pi to make a piano interface. Or you could use a larger transducer to make an affordable ultrasonic soldering iron.

While the vast majority of us are content to plod along with the squishy chiclet keyboards on our laptops, or the cheapest USB membrane keyboard we could find on Amazon, there’s a special breed out there who demand something more. To them, nothing beats a good old-fashioned mechanical keyboard, where each key-press sounds like a footfall of Zeus himself. They are truly the “Chad” of the input device world.

But what if even the most high end of mechanical keyboards doesn’t quench your thirst for spring-loaded perfection? In that case, the only thing left to do is design and build your own. [Matthew Cordier] recently unveiled the custom mechanical keyboard he’s been working on, and to say it’s an elegant piece of engineering is something of an understatement. It may even better inside than it does on the outside.

The keyboard, which he is calling z.48, is based around the Arduino Pro Micro running a firmware generated on kbfirmware.com, and features some absolutely fantastic hand-wiring. No PCBs here, just a rainbow assortment of wire and the patience of a Buddhist monk. The particularly attentive reader may notice that [Matthew] used his soldering iron to melt away the insulation on his wires where they meet up with the keys, giving the final wiring job a very clean look.

Speaking of the keys, they are Gateron switches with DSA Hana caps. If none of those words mean anything to you, don’t worry. We’re through the Looking Glass and into the world of the keyboard aficionado now.

Finally, the case itself is printed on a CR-10 with a 0.3 mm nozzle and 0.2 mm layers giving it a very fine finish. At 70% infill, we imagine it’s got a good deal of heft as well. [Matthew] mentions that a production case and a PCB are in the cards for the future as he hopes to do a small commercial run of these boards. In the meantime we can all bask in the glory of what passes for a prototype in his world.

We’ve seen some exceptionally impressive mechanical keyboards over the years, including the occasional oddity like the fully 3D printed one and even one that inexplicably moves around. But this build by [Matthew] has to be one of the most elegant we’ve ever come across.

[Thanks to DarkSim905 for the tip]

Sometimes we see projects whose name describes very well what is being achieved, without conveying the extra useful dimension they also deliver. So it is with [Prasanth KS]’s Windows PC Lock/Unlock Using RFID. On the face of it this is a project for unlocking a Windows PC, but when you sit down and read through it you discover a rather useful primer for complete RFID newbies on how to put together an RFID project. Even the target doesn’t do it justice, there is no reason why this couldn’t be used with any other of the popular PC operating systems besides Windows.

The project takes an MRFC-522 RFID module and explains how to interface it to an Arduino. In this case the Arduino in question is an Arduino Pro Micro chosen for its ability to be a USB host. The supplied code behaves as a keyboard, sending the keystroke sequence to the computer required to unlock it. The whole is mounted in what seems to be a 3D printed enclosure, and for ease of use the guts of the RFID tag have been mounted in a ring.

As we said above though, the point of this project stretches beyond a mere PC unlocker. Any straightforward RFID task could use this as a basis, and if USB is not a requirement then it could easily use a more run-of-the-mill Arduino. If you’re an RFID newbie, give it a read.

Plenty of RFID projects have made it here before, such as this door lock. And we’ve had another tag in a ring, too.


Filed under: Arduino Hacks, The Hackaday Prize

Old laptops are easy to find and many have a trackpad with a PS/2 interface hardwired into the guts of the laptop. [Build It] wanted one of those trackpads for use in the DIY Raspberry Pi laptop he’s working on. But the Raspberry Pi has no PS/2 input, and he read that a PS/2 to USB adapter wouldn’t be reliable enough. His solution? Wire the trackpad to an Arduino and have the Arduino convert the trackpad’s PS/2 to USB.

After removing a few screws, he had the trackpad free of the laptop. Looking up the trackpad’s part number online he found the solder pads for data, clock and five volts. He soldered his own wires to them, as well as to the trackpad’s ground plane, and from there to his Arduino Pro Micro. After installing the Arduino PS/2 mouse and the Mouse and Keyboard libraries he wrote some code (see his Instructables page). The finishing touch was to use generous helpings of hot glue to secure all the wires, as well as the Arduino, to the back to the trackpad. By plugging a USB cable into the Arduino, he now had a trackpad that could plug in anywhere as a USB trackpad. Watch [Build It] put it all together step-by-step in the video below.

Want something else to do with a trackpad. How about combining sixteen of them into an awesome MIDI controller like [Scott] did?


Filed under: Arduino Hacks

Engineering student Federico Terzi has built an impressive computer interface device reminiscent of a Wiimote.

When talking in person,  you can express meaning using facial expressions, and your hands. Usually this acts to add emphasis to a statement or perhaps to point out a certain object, but what if you could actually type letters based on how your hands move?

Terzi’s aptly named “Gesture Keyboard” does just this, using an Arduino Pro Micro, an MPU-6050 accelerometer, and an HC-06 Bluetooth module for sending signals to his laptop. A Python library using Scikit-learn’s SVM (Support Vector Machine) algorithm then translates the motion readings into characters that appear on the screen.

You can find the code and more information on Terzi’s GitHub page.

Using an Arduino as an HID, Evan Kale turned a “gently used” analog mixer into a computer interface.

Older audio equipment may not have the interfaces that you need to make totally electronic music, but they can be very well-built, so are perhaps worth salvaging. In the video below, Kale salvages potentiometers from an old mixer, then hooks them up to a Pro Micro. This allows the Arduino to take these 12 inputs, and output them as a USB MIDI signal.

Along the way, Kale points out a few very important hacking tricks, including that the library may have a printer ready for you to use, and that analog slider pots many times are logarithmic (or close to it) and need to be calibrated. Also, around 5:25 he introduces viewers to analog multiplexers which can give you eight analog inputs at the cost of three digital and one analog pin.

You can check out more of Kale’s Arduino-based hacks on his YouTube channel here!

To complement his VR experience, Florian Mauer built a controller that could perhaps best be described as a “hand bracelet.”

As virtual reality applications begin to be implemented, one challenge will be finding an interface device, or combination of them that are unobtrusive, yet allow for versatile input. Mauer decided on a design inspired by the gravity control bracelet from the movie “Ender’s Game.” It can be worn similar to how a pistol is held (illustrated here with a virtual pistol), and reportedly doesn’t get in the way when using a keyboard or mouse–at least before the button was added.

The 3D-printed gadget features an IMU, Arduino Pro Micro, as well as a couple buttons for in-game actions. This helps the Leap Motion controller used here to recognize gestures that would be difficult for its camera to pick up otherwise.

In the 2013 adaptation of Ender’s Game, Harrison Ford’s character slips a metallic device over his hand to control gravity in the training room. This scene inspired me as I’ve been trying to imagine VR controllers that can be used alongside mouse+keyboards. The controller used by Ford seemed convenient to put on, offer a lot of finger freedom, and probably allow for throwing VR objects without falling off.

You can see more information on this promising project on Mauer’s website here.



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