Every time we watch Minority Report we want to make wild hand gestures at our computer — most of them polite. [Rootsaid] wanted to do the same and discovered that the PAJ7620 is an easy way to read hand gestures. The little sensor has a serial interface and can recognize quite a bit of hand waving. To be precise, the device can read nine different motions: up, down, left, right, forward, backward, clockwise, anticlockwise, and wave.
There are plenty of libraries to read it for common platforms. If you have an Arduino that can act as a keyboard for a PC, the code almost writes itself. [Rootsaid] uses a specific library for the PAJ7620 and another — Nicohood — for sending media keys.
With those two libraries, it is very simple to write the code. You simply read a register from the sensor and determine which key to send using the Nicohood library. The serial communications is I2C and there’s a tiny optical sensor onboard along with an IR LED.
Of course, you could send other keys than media controls. We wouldn’t mind going back and forward on web pages with a gesture, for example.
We’ve seen gesture recognition with radar. We’ve also seen it with ultrasonics.
YouTuber “Absorber Of Light” needed to cut thousands of tiny aluminum pieces with a chop saw, and after paying someone to do this for him, decided to instead automate the process.
His system is controlled by an Arduino Uno, and moves strips of aluminum under the saw using stepper motor and threaded rod assembly—a sort of very simple CNC. Once in position, a second stepper activates a linear actuator via a physical H-bridge relay setup with cams and microswitches. This actuator pushes the saw into the aluminum strip, cutting it to an impressive ±.002 in, or ~.05 mm tolerance.
You can see it in action in the video below and find the project’s code in the description.
Cutting thousands of these small pieces of aluminum with the help of an Arduino and a couple of stepper motors. They will eventually become brackets to fasten computer monitors to metal enclosures.
The brackets measure .750″ x .547″ x .125″, tolerance is quite decent at + or – .002″ I tried to keep the code as simple as possible because I’m not much of a programmer and didn’t want to spend too much time on it. The loop is triggered by the Arduino reset button. The linear actuator is controlled by an H-bridge with 4 simple switches activated by one of the steppers.
Upon obtaining a small toy piano, Måns Jonasson went to work “Arduinoizing” it with 30 solenoids to hammer out tunes.
A MIDI shield is used to pipe commands from a computer to the Arduino Mega that’s used for control, and after experimenting with discreet wiring and electronics for each of the solenoids, he switched to motor shields as outlined here to simplify the setup. This, along with a new version of the solenoid holders he designed, cleaned up the build nicely, allowing it to play a plinky version of the Super Mario Bros. theme song.
Be sure to check out the Mario themed auto-concert in the video below, plus a video outline of its construction, below.
This particular piano’s keys use lever action to strike thin steel tines. These tines are spaced just wide enough for tiny 5V solenoids to fit over them. Once [Måns] got a single solenoid striking away via MIDI input, he began designing 3D printed holders to affix them to the soundboard.
Everything worked with all thirty solenoids in place, but the wiring was a bird’s nest of spaghetti until he upgraded to motor driver shields. Then he designed a new bracket to hold eight solenoids at once, with a channel for each pair of wires. Every eight solenoids, there’s an Arduino and a motor shield.
The resulting junior player piano sounds like someone playing wind chimes like a xylophone, or a tiny Caribbean steel drum. Check out the build video after the break.
Hate the sound of toy pianos, but dig the convenient form factor? Turn one into a synth.
Makerspace i3Detroit was the recent recipient of a free yet non-functioning CNC router. While out of commission when received, the device’s mechanical components and motors appeared to be in operational condition, plus it had a large work surface. The decision was made to get the CNC up and running for now, with the eventual goal of turning it into a plasma cutter.
First, they booted up its (Windows 95) computer and replaced a power supply on the controller. An adapter board for the controller was then built using info from this Arduino Forum post, allowing the router to be controlled with an Arduino Mega running grbl firmware.
Although there is still some work to do, it can be seen happily jogging along in the video below, and appears well on its way to becoming a usable machine!
We are excited to announce a new partnership with Chirp, a London-based company on a mission to simplify connectivity using sound. Chirp’s machine-to-machine communications software enables any device with a loudspeaker or microphone to exchange data via inaudible sound waves.
Starting today, our Chirp integration will allow Arduino-powered projects to send and receive data wirelessly over sound waves, using just microphones and loudspeakers. Thanks to some compatible libraries included in the official Arduino Library Manager and in the Arduino Create — as well as further comprehensive documentation, tutorials and technical support — it will be easy for anyone to add data-over-sound capabilities to their Arduino projects.
Creative applications of Arduino and Chirp include, but certainly are not limited to:
Triggering events from YouTube audio
Securely unlocking a smart lock with sound
Sending Wi-Fi credentials to bring offline devices onto a Wi-Fi network
Having a remote control that only interacts with the gadgets in the same room as you
“Connectivity is a fundamental asset for our users, as the demands of IoT uptake require devices to communicate information seamlessly and with minimal impact for the end user. Chirp’s data-over-sound solution equips our boards with robust data transmission, helping us to deliver enhanced user experiences whilst increasing the capabilities of our hardware at scale,” said Massimo Banzi, Arduino co-founder.
“Sound is prevailing as a highly effective and versatile means of seamless data transmission, presenting developers with a simple to use, software-defined solution which can connect devices. Working with Arduino to extend the integration of data-over-sound across its impressive range of boards will not only increase the reach of Chirp’s technology, but provide many more developers with an accessible and easily integrated connectivity solution to help them drive their projects forward in all purposes and environments. We can’t wait to see what the Arduino community builds,” commented James Nesfield, Chirp CEO.
To learn how to send data with sound with an Arduino Nano 33 BLE Sense and Chirp, check out this tutorial and visit Chirp website here.
We’re not going to question why [Absorber Of Light] needs to cut a bazillion little fragments of aluminum stock. We assume his reasoning is sound, so all we’re interested in is the automated chop saw he built to make the job less tedious, and potentially less finger-choppy.
There are probably many ways to go about this job, but [Absorber] leaves few clues as to why he chose this particular setup. Whatever the reason, the build looks like fun, with a long, stepper-driven threaded rod pushing a follower down a track to a standard chop saw. The aluminum stock rides in the track and gets pushed out a set amount before being lopped off cleanly as the running saw is lowered by a linear actuator. The cycle then repeats until the stock is gone.
An Arduino controls the stock-advance stepper in the usual way, but the control method for the linear actuator is somewhat unconventional. A second stepper motor has two cams offset by 180° on the shaft. The cams actuate four microswitches which are set up in an H-bridge configuration. The stepper swivels back and forth to run the linear actuator first in one direction then the other, with a neutral position in between. It’s an interesting approach using mechanical rather than the typical optical isolation. Check it out in action in the video below.
We’ll admit to some curiosity as to the use of the coupons this rig produces, so maybe we’ll get lucky with some details from [Absorber Of Light] in the comment section. After all, we knew exactly what the brass tubes being cut by the similar “Auto Mega Cut-O-Matic” were being used for.
Remember back in the early-to-mid 2000s when pretty much every cheap USB keyboard you could find started including an abundance of media keys in its layout? Nowadays, especially if you have a customized or reduced-sized mechanical keyboard, those are nowhere to be seen. Whenever our modern selves need those extra keys, we have to turn to external peripherals, and [Gary’s] Knobo is one that looks like it could’ve come straight out of a fancy retail package.
The Knobo is a small macro keypad with 8 mechanical Cherry-style keys and a clickable rotary encoder knob as its main feature. Each key and knob gesture can be customized to any macro, and with five gestures possible with the knob, that gives you a total of thirteen inputs. On top of that, the build and presentation look so sleek and clean we’d swear this was a product straight off of Teenage Engineering’s money-printing machine.
The actions you can do with those inputs range from simple media controls with a volume knob all the way to shortcuts to make a Photoshop artist’s life easier. Right now you can only reprogram the Knobo’s Arduino-based firmware with an In-Circuit Serial Programmer to change what the inputs do, but [Gary] is currently working on configuration software so that users without any programming knowledge will be able to customize it too.
If you have ever thought what is missing in your life is a pedestrian traffic light, be sure to check out Ronald Diaz’s recent build.
The project uses a pair of lights that Diaz had in storage for the past decade, to which he’s finally added an Arduino controller that takes care of the walk/stop sequence.
The device is initiated by a pushbutton, which then cycles between a red light that implores pedestrians to wait, to a green signal that tells people to go, to a flashing red light and back to solid red. A piezo speaker was also included, which plays sounds based around actual Australian tones depending on the light state.
Code can be found over on GitHub, and you can see it demonstrated in the video below.
The latest itty bitty powerhouse from PJRC has been released this week. The teensy line of dev boards has hit 4.0! They have managed to keep a tiny footprint, like you’ve come to expect from the Teensy. They’ve gained some serious horsepower thanks to the ARM Cortex-M7 running running at […]
