[Kenneth] is using an Arty A7 FPGA development board which is a great fit for purpose, having plenty of I/O pins and being relatively easy to work with for the home tinkerer. This is an important consideration, as many industrial strength FPGAs require software licences to use which can easily stretch into the tens of thousands of dollars.
The 6502 is placed on a breadboard, and a nest of wires connects it to the PMOD interfaces of the Arty board. Then it’s a simple job of mapping out the pins on the FPGA and you’re good to go. Due to the 6502’s design it’s possible to step through instructions one at a time, and this is particularly useful on a basic homebrew build so [Kenneth] was sure to implement this functionality.
It’s all capped off with the FPGA sending the 6502 a starting address and a series of NOPs, to demonstrate the setup is capable of running the 6502 with instructions fed from the FPGA. It’s a project that shows the fundamentals of interfacing two technologies that are widely spread out in sophistication, and acts as a great base for further experimentation.
You often hear that art imitates life, but sometimes technology does too. Pliant Energy Systems’ Velox robot resembles an underwater creature more than it does a robot because it uses undulating fins to propel itself, as you can see in the video below.
The video shows the beast skating, but also swimming, and walking. It really does look more like a lifeform than a device. According to the company, the robot has excellent static thrust/watt and is resistant to becoming entangled in plants and other debris.
The build relies on special contact lenses, which [Kyle] suggests are best sourced by searching for “electric blue contact lenses”. These glow in the presence of UV light, which here is provided by a strip of UV LEDs embedded into Thor’s helmet from the recent Marvel movies.
The concept is simple, but the attention to detail is what makes this project a winner. Not content with an earlier build that was a tangle of wires and uncomfortable to use, [KyleofAsgard] made some smart upgrades. The battery for the LEDs and all circuitry is built into the helmet, making it easy to take on and off on those long convention days. For a more impressive effect, a relay is used to turn the LEDs on by remote control with a 433MHz module. This allows [Kyle] or an assistant to trigger the effect covertly, adding plenty of drama when the eyes suddenly begin to shine. It’s all done with off-the-shelf parts that even a novice could put together.
Measuring power transfer through a circuit seems a simple task. Measure the current and voltage, do a little math courtesy of [Joule] and [Ohm], and you’ve got your answer. But what if you want to design an instrument that does the math automatically? And what if you had to do this strictly electromechanically?
That’s the question [Shahriar] tackles in his teardown of an old lab-grade wattmeter. The video is somewhat of a departure for him, honestly; we’re used to seeing instruments come across his bench that would punch a seven-figure hole in one’s wallet if acquired new. These wattmeters are from Weston Instruments and are beautiful examples of sturdy, mid-century industrial design, and seem to have been in service until at least 2013. The heavy bakelite cases and sturdy binding posts for current and voltage inputs make it seem like the meters could laugh off a tumble to the floor.
But as [Shahriar] discovers upon teardown of a sacrificial meter, the electromechanical movement behind the instrument is quite delicate. The wattmeter uses a moving coil meter much like any other panel meter, but replaces the permanent magnet stator with a pair of coils. The voltage binding posts are connected to the fine wire of the moving coil through a series resistance, while the current is passed through the heavier windings of the stator coils. The two magnetic fields act together, multiplying the voltage by the current, and deflect a needle against a spring preload to indicate the power. It’s quite clever, and the inner workings are a joy to behold.
We just love looking inside old electronics, and moving coil meters especially. They’re great gadgets, and fun to repurpose, too.
Join us for the podcast, available on all major podcasting platforms, as Editors Mike Szczys and Elliot Williams attempt the impossible task of distilling the entire year into a one hour discussion. We’ve included every story mentioned in the podcast, and a few more, in the show notes here. But since we can’t possibly mention every awesome hack, we encourage you to share your favorites, and pat the writers on the back, by leaving a comment below.
Take a look at the links below if you want to follow along, and as always, tell us what you think about this episode in the comments!
The ability to execute code in parallel is crucial in a wide variety of scenarios. Concurrent programming is a key asset for web servers, producer/consumer models, batch number-crunching and pretty much any time an application is bottlenecked by a resource.
It’s sadly the case that writing quality concurrent code can be a real headache, but this article aims to demonstrate how easy it is to get started writing threaded programs in Python. Due to the large number of modules available in the standard library which are there to help out with this kind of thing, it’s often the case that simple concurrent tasks are surprisingly quick to implement.
We’ll walk through the difference between threads and processes in a Python context, before reviewing some of the different approaches you can take and what they’re best suited for.
It’s not that [GreatScott!] isn’t aware that 3D-printed motors are a thing; after all, the video below mentions the giant Halbach array motor we featured some time ago. But part of advancing the state of the art is to replicate someone else’s results, so that’s essentially what [Scott!] attempted to do here. It also builds on his recent experiments with rewinding commercial BLDCs to turn them into generators. His first step is to recreate the stator of his motor as a printable part. It’s easy enough to recreate the stator’s shape, and even to print it using Proto-pasta iron-infused PLA filament. But that doesn’t come close to replicating the magnetic properties of a proper stator laminated from stamped iron pieces. Motors using the printed stators worked, but they were very low torque, refusing to turn with even minimal loading. There were thermal issues, too, which might have been mitigated by a fan.
So not a stunning success, but still an interesting experiment. And seeing the layers in the printed stators gives us an idea: perhaps a dual-extruder printer could alternate between plain PLA and the magnetic stuff, in an attempt to replicate the laminations of a standard stator. This might help limit eddy currents and manage heating a bit better. Continue reading “Can You 3D-Print A Stator For A Brushless DC Motor?”→