The Quadrivium EnsembleBot Is A Labour Of Love

October 19, 2021 by 5 Comments

The Quadrivium EnsembleBot project is a mashup between old school musical instruments and the modern MIDI controlled world. Built by a small team over several years, these hand crafted instruments look and sound really nice.

The electronics side of things is taken care of with a pile of Arduinos and off-the-shelf modules, but that doesn’t mean the design isn’t well thought through, if a little more complicated than it could be in places. Control is taken care of with a PC sending commands over the USB to an Arduino 2560. This first Arduino is referred to as the Master Controller and has the immediate job of driving the percussive instruments as well as other instruments that are struck with simple solenoids. All these inductive loads are switched via opto-isolators to keep any noise generated by switching away from the microcontroller. A chain of four sixteen-channel GPIO expander modules are hung off the I2C bus to give even more opto-isolated outputs, as even the Arduino 2560 doesn’t quite have enough GPIO pins available. The are a number of instruments that have more complex control requirements, and these are connected to dedicated slave Arduinos via an SPI-to-CAN module. These are in various states of development, which we’ll be keeping our beady eyes on.

One of the more complex instruments is the PipeDream61 which is their second attempt to build a robotic pipe organ. This is powered by a Teensy, as they considered the Arduino to be a little too tight on resources. This organ has a temperature controller using an ATTiny85, in order to further relieve the main controller of such a burden and simplify the development a little.

Another interesting instrument is Robro, which is a robotic resophonic guitar which as they say is still work in progress despite how long they have been trying to get it to work. There’s clearly a fair bit of control complexity here, which is why it is taking so much fiddling (heh!) to get it work.

This project is by no means unique, lately we’ve covered controlling a church organ with MIDI, as well as a neat Arduino Orchestra, but the EnsembleBot is just so much more.

Continue reading “The Quadrivium EnsembleBot Is A Labour Of Love” →

The Low-Down On Long-Wave: Unlicensed Experimental Radio

October 19, 2021 by 70 Comments

In the 125 years since Marconi made his first radio transmissions, the spectrum has been divvied up into ranges and bands, most of which are reserved for governments and large telecom companies. Amidst all of the corporate greed, the “little guys” managed to carve out their own small corner of the spectrum, with the help of organizations like the American Radio Relay League (ARRL). Since 1914, the ARRL has represented the interests of us amateur radio enthusiasts and helped to protect the bands set aside for amateur use. To actually take advantage of the wonderful opportunity to transmit on these bands, you need a license, issued by the FCC. The licenses really aren’t hard to get, and you should get one, but what if you don’t feel like taking a test? Or if you’re just too impatient?

Well, fear not because there’s some space on the radio spectrum for you, too.

Welcome to the wonderful world of (legal!) unlicensed radio experimentation, where anything goes. Okay, not anything  but the possibilities are wide open. There are a few experimental radio bands, known as LowFER, MedFER, and HiFER where anyone is welcome to play around. And of the three, LowFER seems the most promising. Continue reading “The Low-Down On Long-Wave: Unlicensed Experimental Radio” →

The PinePhone Pro Is Here. But It’s Still Probably Not The Year Of Open-Source Linux On The Smartphone

October 19, 2021 by 82 Comments

A trope in open source commentary over the last decades has been the phrase “Is this the year of Linux on the desktop?”, as though the open source OS will finally break through and challenge Windows. In fact the process has been one of stealth rather than explosive growth, as the likes of ChromeOS with its Linux underpinnings become the go-to choice for an inexpensive consumer laptop. In the phone arena the same has happened with Android, as most users have no idea that a Linux foundation lies beneath their Samsung Galaxy or Google Pixel.

Fully open-source via Android on the phone has been very slow to arrive, but could that be changed by the arrival of Pine64’s PinePhone Pro? The new device will be available alongside their existing PinePhone, and will continue the dream of a fully open-source mobile phone with its increased-specification hardware.

As much as the specs of one black slab versus another matter, at its heart is a 1.5 GHz Rockchip RK3399S hexa-core SoC alongside 4 GB of dual-channel LPDDR4 RAM. This compares well to the original PinePhone’s quad-Core Allwinner A64 at 1.152 GHz and 3 GB LPDDR3 RAM, so it’s clear that there is plenty of capability in this phone.

Any phone whether open-source or not will however live or die on the quality of its software and support, so for this model to be a real success outside the realm of extreme open-source devotees we think that Pine64 will need to be prepared to up their game when it comes to what happens after hardware delivery. It’s fair to say that some of their previous products have been a little lacklustre in this department, with hardware bugs remaining unfixed. Their approach of relying on the community of users to deliver software support has not so far returned a stable experience for users of the original PinePhone. We understand that their intention is to provide a developer’s phone, but developers need to place phonecalls and take pictures too.

We’ve seen some PinePhone owners commenting to this effect, and though we’re fans of Pine64 and like what they are trying to do, we have to admit that those users have a point. If they were prepared to put some effort into software development to the extent of providing an official OS image with let’s say Plasma Mobile, a working phone app, a working web browser, and responsive phone features such as instant on and off, even at the expense of charging more for the phone itself, we think that they’ll be on to a winner. Otherwise they’ll remain as the really cool open-source phone that only your kernel-wizard friends own, and even then they use a Google Pixel as their everyday phone. Please Pine64, prove us wrong!

Last month our colleague Brian Cockfield took us on a tour of his PinePhone.

Drone And High Voltage Spin Up This DIY Corona Motor

October 19, 2021 by 5 Comments

The average Hackaday user could probably piece together a rough model of a simple DC motor with what they’ve got kicking around the parts bin. We imagine some of you could even get a brushless one up and running without too much trouble. But what about an electrostatic corona motor? If your knowledge of turning high voltage into rotational energy is a bit rusty, let [Jay Bowles] show you the ropes in his latest Plasma Channel video.

Like many of his projects, this corona motor relies on a few sheets of acrylic, a handful of fasteners, and a healthy dose of physics. The actual construction and wiring of the motor is, if you’ll excuse the pun, shockingly simple. Of course part of that is due to the fact that the motor is only half the equation, you still need a high voltage source to get it running.

An earlier version of the motor ended up being too heavy.

In this case, [Jay] is revisiting his earlier experiments with atmospheric electricity to provide the necessary jolt. One side of the motor is connected to a metallic mesh electrode that’s carried 100 m into the air by a DJI Mini2 drone, while the other side is hooked up to several large nails driven into the ground.

The potential between the two gets the motor spinning, and makes for an impressive demonstration, but it’s not exactly the most practical way to experiment with your new corona motor. If you’d rather get it running on the workbench, he also shows that a more traditional high voltage source like a Van de Graaff generator will do the job nicely. As an added bonus, it can even power the device wirelessly from a few feet away.

So what can you do with a corona motor? While [Jay] is quick to explain that these sort of devices aren’t exactly known for their torque, he does show that his motor is able to lift a 45 gram weight suspended from a string. That’s frankly more power than we expected, and makes us wonder if there is some quasi-practical application for this contraption. If there is we suspect it’ll be featured in a future Plasma Channel video, so stay tuned.

Continue reading “Drone And High Voltage Spin Up This DIY Corona Motor” →

POLF: Retro 3D Game Uses Only A Character Display

October 18, 2021 by 11 Comments

Got a retrocomputing itch? So does [David Given], and luckily for us all he indulged it by writing POLF: a first-person 3D game for the Commodore PET that uses only the system’s 40×25 text mode character display for visuals. It’s a fantastic achievement, considering that the 80s-era computer boasts 32 kB of memory and doesn’t even have a graphical display.

Each level has an 8×8 layout.

Each level in POLF is a small, maze-like room in which one’s goal is to play a sort of cross between billiards and golf, aiming to move the round “ball” object into the square “hole” object. The 3D view is rendered using raycasting, which is a way of efficiently drawing a workable 3D perspective using limited resources. Raycasting can only do so much, but as a method it works fantastically within its limitations, and there are useful tutorials out there that lay the process bare.

The GitHub repository for the project is here, and it should run on any 40-column screen PET with at least 16 kB of RAM. Watch it in action in the video, embedded below. (Hint: the little bar graphs under the compass headings at the bottom of the screen represent the player’s proximity to the ball and hole objects. )

Continue reading “POLF: Retro 3D Game Uses Only A Character Display” →

A Microwave Frequency Doubler

October 18, 2021 by 14 Comments

It is an age-old problem. You have a 2.5 GHz source and you want it at 5 GHz. You need a frequency doubler. [All Electronics Channel] has an interesting video that talks not only about the theory of such a device but shows a practical one made with copper strips on a blank PCB substrate.

A fun thing about microwaves is that even little strips of copper are circuit elements since the wavelength at 2.5 GHz is only 12cm. That means a quarter-wave stub is only 3 cm — just over an inch.

The construction technique used is simple and, as he points out, experimenting with a real circuit will give you much more feel for how these circuits work than just reading and working out the math.

The multiplier drives an amplifier into nonlinearity which, of course, generates harmonics. Then a bandpass filter selects the second harmonic. If you haven’t dealt with stub circuits before, you might want to read up on how a piece of copper connected at one end can act like an inductor, a capacitor, or even a tuned circuit.

If you want more detail on the copper tape technique, we can help. If you don’t want to double frequency, maybe you would prefer to try voltage.

Continue reading “A Microwave Frequency Doubler” →

A game board with five LEDs and a hand shining a laser pointer at it

Laser Pointer And Arduino Make A Minimalistic Shooting Game

October 18, 2021 by 7 Comments

Video games are great and all, but sometimes you just want the thrill of manipulating actual objects in addition to watching action on a screen. This must have been the reason why Nintendo’s Duck Hunt became so popular despite the simplicity of its gameplay. Prolific hacker [mircemk] similarly made a computer-plus-physical game called “Laser Shooter“, which somehow reminds us of the good old NES game.

The game is based on an Arduino Nano, to which five LEDs as well as five photoresistors (LDRs) are connected. When the game is started, the LEDs light up at random and the player has a limited time to “shoot” the corresponding LDR with a laser pointer. This time limit is decreased as the game progresses, and the game is over once the player fails to hit the target on time. The “Game Over” message is accompanied by a sad tune, but luckily no giggling dog.

Complete schematics and code are available for anyone willing to try their hand at replicating or improving this game. And no, you can’t simply sweep your laser across the five LDRs all the time, because you lose if you shoot at the wrong target. For more laser pointer-based games, try this Laser Command clone or this laser tag badge system.

Continue reading “Laser Pointer And Arduino Make A Minimalistic Shooting Game” →