Day: February 16, 2021

A Hydraulic Bench Vise, Made On The Bench

February 16, 2021 by 21 Comments

When we sit down to a build video and see that it’s from [Workshop From Scratch], we know it’ll be a good one, full of plenty of gratuitous metal-wrangling with the promise of an ingenious and useful take on a workshop essential at the end. The home made hydraulic bench vise is the latest from that particular workshop, so settle down with the video below the break for a treat.

Unlike the lead screw we’d expect from a more conventional vise, this one uses a hydraulic pull cylinder and its associated compressor which is powered by compressed air. A substantial vise frame is constructed around the cylinder from thick steel plate, with some careful welding and grinding to ensure a smooth finish.  The result is substantial clamping force with a very smooth and quick action, which doesn’t overhang the edge of the bench in the way a more traditional one does. The hydraulic tube is tucked away through a hole in the bench, and the foot-operated pump lies out of sight on the floor.

Looking at this vise with blacksmith-trained eyes, it raises the question of how it might perform were something in it to be hammered. Overhanging vises are vulnerable to splitting when hammered, so there’s the possibility that this one with its flat mounting might fare a little better. Either way it would be an asset to any workshop.

When it comes to vises, [Workshop From Scratch] is where we saw that magnetic vise earlier last year.

Continue reading “A Hydraulic Bench Vise, Made On The Bench” →

BASIC: Cross-Platform Software Hacking Then And Now

February 16, 2021 by 124 Comments

Surely BASIC is properly obsolete by now, right? Perhaps not. In addition to inspiring a large part of home computing today, BASIC is still very much alive today, even outside of retro computing.

There was a time, not even that long ago, when the lingua franca of the home computer world was BASIC. This wasn’t necessarily always the exact same BASIC; the commands and syntax differed between whatever BASIC dialect came with any given model of home computer (Commodore, Atari, Texas Instruments, Sinclair or any of the countless others). Fortunately most of these licensed or were derived from the most popular microcomputer implementation of BASIC: Microsoft BASIC.

BASIC has its roots in academics, where it was intended to be an easy to use programming language for every student, even those outside the traditional STEM fields. Taking its cues from popular 1960s languages like FORTRAN and ALGOL, it saw widespread use on time-sharing systems at schools, with even IBM joining the party in 1973 with VS-BASIC. When the 1970s saw the arrival of microcomputers, small and cheap enough to be bought by anyone and used at home, it seemed only natural that they too would run BASIC.

The advantage of having BASIC  integrated into these systems was obvious: not only were most people who bought such a home computer already familiar with BASIC, it allows programs to be run without first being compiled. This was good, because compiling a program takes a lot of RAM and storage, neither of which were plentiful in microcomputers. Instead of compiling BASIC source code, BASIC interpreters would interpret and run the code one line at a time, trading execution speed for flexibility and low resource use.

After turning on one’s microcomputer, the BASIC interpreter would usually be loaded straight from an onboard ROM in lieu of a full-blown operating system. In this interpreter shell, one could use the hardware, write and load BASIC programs and save them to tape or disk. Running existing BASIC code as well as compiled programs on one’s computer, or even typing them in from a listing in a magazine all belonged to the options. As BASIC implementations between different home computers were relatively consistent, this provided for a lot of portability.

That was then, and this is now. Are people actually still using the Basic language?

Continue reading “BASIC: Cross-Platform Software Hacking Then And Now” →

Continuous Excitation Piano Machine Looks Nervous, Sounds Grand

February 16, 2021 by 20 Comments

It’s not every day we see a grand piano with a Raspberry Pi inside, let alone one with 96 motors, but sometimes we get lucky. The contraption in question is one developed by [Konstantin Leonenko], as part of a collaboration with composer [Patricia Alessandrini] for a piece she created inspired by Ada Lovelace. Specifically, [Patricia] was inspired by Ada’s idea that an “analytical machine” would, someday, be able to create music on its own. [Konstantin] and [Patricia] worked together to make a machine that would learn from it’s human co-performers and create music with them.

Their creation, rather than just one tricked-out keyboard, is actually a portable attachment that can be easily fitted to any grand piano. Each of the device’s 96 motors drives a plastic “finger” that excites the piano’s strings. The result is a sound unlike any other — and you really need to experience it so click through that link at the top for the demo video.

Rather cleverly, the fingers are designed such that their dynamics help to mask the sound of the motor (a must for performances) while simultaneously enhancing the string’s timbre. Like any project, this one went through a number of iterations over the two-year design process, and even spun off into an entirely new, glove-based version.

We’ve seen some awesome music tech hacks, and this one fits right in with the rest. It’s always exciting to see an instrument as ubiquitous as the piano be used in new and refreshing ways. Be sure to check out the link at the top for a video of this incredible instrument in action!

Manned Electric Helicopter With 7 Tail Rotors

February 16, 2021 by 56 Comments

One of the best things to come from the growing drone industry is the development of compact and powerful brushless motors. We’ve seen several multi-rotors capable of carrying a human, but electric helicopters are rare. [OskarRDA] decided to experiment with this, converting his single-seat ultralight helicopter to electric power and giving it seven tail rotors in the process. Flight footage after the break.

The helicopter in question started life as a Mosquito Air, a bare-bones kit helicopter originally powered by a two-stroke engine. The engine and gearbox were replaced with an EMRAX 228 109 kW brushless motor. Initially, he used the conventional drive-shaft powered tail rotor but wanted to experiment with multiple smaller rotors powered by separate motors, which has several advantages. He only really needed four of the 5008 or 5010 size motors with 18″ props to get comparable thrust, but he added more for redundancy. The new setup was also lighter, even with its independent batteries, at 7.5 kg compared to the 8.1 kg of the old tail rotor assembly.

One of the major advantages of a conventional helicopter over a multirotor is the ability to autorotate safely to the ground if the engine fails. A coupled tail rotor bleeds some energy from the main rotor while autorotating, but since the tail rotor has independent power in this case, it allows all the energy to be used by the main rotor, theoretically decreasing decent speed by 120 feet per second. [OskarRDA] did some engine failure and autorotation test flights, and the results were positive. He likes his new tail rotors enough that he doesn’t plan on going back to a single large rotor.

Power for the main motor is provided by a 7.8 kWh, 40 kg LiPo battery pack mounted beneath the seat. Theoretically, this would allow flight times of up to 27 minutes, but [OskarRDA] has kept most of his flights to 10 minutes or less. He didn’t add any electronic gyro for stabilization, but he did add some electronic coupling between the main motor and tail motors, to reduce the torque correction required by the pilot. Even so, it is clear from the flight footage that [OskarRDA] is a skilled helicopter pilot. Continue reading “Manned Electric Helicopter With 7 Tail Rotors” →