In years gone by, trying out a new circuit probably would have meant heating up a soldering iron. Solderless breadboards have made that even easier and computer simulation is easier still, but there’s something not quite as satisfying about building a circuit virtually. [Thedeuluiz] has a way to get some of the best of both worlds with the RTSpice project.
The idea is simple in concept, although not as simple in execution. The program does a Spice-like simulation of a circuit and can accept input and produce output from a PC’s sound card. Obviously, that means you can’t simulate RF circuits — at least not at the input and the output. It also means the simulation has to run lightning fast to keep up with the sound card sample rate. According to the author, it works best with modest circuits but exactly how big you can go will depend on your hardware.
Steel Battalion was released for the Xbox in 2002, and remains one of the most hardcore mech simulators of all time. It became legendary for its huge twin-stick controller covered in buttons, and for deleting your save game if you failed to eject in time. It took giant robot gaming to a new level, but fundamentally, you were still playing in front of a TV at home. Things really got serious in 2015, with the completion of the Big Steel Battalion Box – the battlemech cockpit of your dreams.
If you’re thinking this is just a television in a dark room with some stickers, you’d be very wrong. The Imgur thread covers the build process, and it’s one heck of a ride. Things started with a custom cabinet being built, intentionally sized to induce claustrophobia. There’s a swivelling seat with a 4-point harness, and a hatch to seal the player inside. During initial testing of the box to determine how dark it was, one of the makers was trapped inside and had to call for help. That should highlight how serious the build really is.
The controller was modified and hooked up to custom electronics to add realistic effects. Get hit? Feel the seat rumble thanks to motors and a subwoofer in the base. Mech terminally damaged? The entire cockpit is bathed in flashing red light. There’s even smoke effects rigged up to make things even more stressful during battle.
The entire setup is connected to the outside world, where a coach can view the action inside through a video feed from the Xbox and several internal cameras. A basic manual is provided to help the coach keep the player alive during their first moments of combat. This is courtesy of a custom intercom setup, built using surplus Chinese aviation headsets. There’s even a red telephone to give that authentic military feel.
Father-and-son team [Wade] and [Ben Vagle] have developed and extensively tested two great walker designs: TrotBot and the brand-new Strider. But that’s not enough: their website details all of their hard-earned practical experience in simulating and building these critters, on scales ranging from LEGO-Technic to garage-filling (YouTube, embedded below). Their Walker ABC’s page alone is full of tremendously deep insight into the problem, and is a must-read.
These mechanisms were designed to be simpler than the Jansen linkage and smoother than the Klann. In particular, when they’re not taking a stroll down a beach, walker feet often need to clear obstacles, and the [Vagles’] designs lift the toes higher than other designs while also keeping the center of gravity moving at a constant rate and not requiring the feet to slip or slam into the ground. They do some clever things like adding toes to the bots to even out their gaits, and even provide a simulator in Python and in Scratch that’ll help you improve your own designs.
If you wanted a robot that simply moved, you’d use wheels. We like walkers because they look amazing. When we wrote [Wade] saying that one of Trotbot’s gaits looked animal-like, he pointed out that TrotBot got its working name from a horse-style gait (YouTube). Compared to TrotBot, the Strider family don’t have as much personality, but they run smoother, faster, and stronger. There’s already a 3D-printing-friendly TrotBot model out there. Who’s going to work something up for Strider?
We like a good video game as much as the next person. Heck, a few hours wasted with “Team Fortress 2” on a couple of big monitors is a guilty pleasure we’ll never be ashamed of. But this starship bridge simulation console brings immersive gameplay to a new level, and we wholeheartedly endorse it even if we don’t quite get it.
The game in question is “Artemis Spaceship Bridge Simulator”, a game played by anywhere from 2 to 11 players, each of whom mans a different station on the bridge of a generic starship, from Engineering to Communications to the vaunted Captain’s chair. The game is generally played on laptops linked together in a LAN with everyone in the same room, and as cool as that sounds, it wasn’t enough for [Angel of Rust]. The whole mousing back and forth to control the ship seemed so 21st-century, so he built detailed control panels for each of the bridge stations. The level of detail is impressive, as is the thought put into panel layouts and graphics. The panels are mostly acrylic in MDF frames, which allows for backlighting to achieve the proper mood. With the help of a bunch of Arduinos, everything talks to the game software over DMX, the protocol used mainly for stage lighting control. There’s a cool demo video below.
This is uber-nerd stuff, and we love it. Pyrotechnics and atmospherics would be a great addition for “realistic” battles, and dare we hope that someday this ends up on a giant Stewart platform flight simulator for the ultimate experience?
I’ve always appreciated simulation tools. Sure, there’s no substitute for actually building a circuit but it sure is handy if you can fix a lot of easy problems before you start soldering and making PCBs. I’ve done quite a few posts on LTSpice and I’m also a big fan of the Falstad simulator in the browser. However, both of those don’t do a lot for you if a microcontroller is a major part of your design. I recently found an open source project called Simulide that has a few issues but does a credible job of mixed simulation. It allows you to simulate analog circuits, LCDs, stepper and servo motors and can include programmable PIC or AVR (including Arduino) processors in your simulation.
The software is available for Windows or Linux and the AVR/Arduino emulation is built in. For the PIC on Linux, you need an external software simulator that you can easily install. This is provided with the Windows version. You can see one of several videos available about an older release of the tool below. There is also a window that can compile your Arduino code and even debug it, although that almost always crashed for me after a few minutes of working. As you can see in the image above, though, it is capable of running some pretty serious Arduino code as long as you aren’t debugging.
In the last installment of Circuit VR, we walked around a simplified buck converter. The main simplification was using a constant PWM signal. The result is that the output voltage is a fixed fraction of the input voltage. For a regulator, the pulse width will need to depend on the output voltage so that any changes in the output are self-correcting. So this time, we’ll make a regulator, although we’ll still use a few Spice elements you’d have to replace in a practical design. In particular, we’ll assume you can generate a triangle wave, which is easy enough, and produce a stable 2.5 V reference.
The idea is to take a voltage reference and compare it to the output. We’ll think of the difference between the two as an error voltage, and use a comparator combined with a triangle wave generator to produce a PWM signal that is proportional to the error, and thus works to hold the output voltage constant.