Lego Wheels And Tracks Benchmarked For Your Pleasure

May 4, 2021 by Zoe Skyforest 7 Comments

For many people, Lego is their first entry into the world of engineering. With the Technic line of building blocks complete with all manner of gears and shafts and wheels, there’s a ton of fun to be had while learning about the basic principles of mechanical things. The [Brick Experiment Channel] takes Lego quite seriously in this context, and has collected data concerning the performance of a variety of Lego wheels and tracks.

The testing setup is simple. A small vehicle is fitted with a particular set of Lego wheels or tracks. Then, it’s placed on an inclined wooden board. The angle of inclination is then increased until the vehicle neither climbs the board nor slips down it. This angle can then be used to calculate the coefficient of friction of the given tyre or track set. [Brick Experiment Channel] filmed this testing and collected data on 33 different wheel and track combinations, publishing it in the description of the Youtube video.

Interestingly, the date of release of the various parts is recorded with the data. This is interesting as one would expect older rubber parts to lose grip with age, however, the release date of the parts obviously does not correspond with the manufacturing date, so the utility of this is somewhat unclear. There’s also some surprising results, with what appear to be soft, flat and smooth rubber wheels performing somewhat worse than those with curved profiles that you’d expect to have less contact patch. Regardless, it’s the best data we’ve ever seen in this field and we think it’s great that it was collected and shared with the broader Lego community. We look forward to seeing more of this in future, as it’s obviously something of great use to builders. We can imagine it would have proved handy when [Brick Experiment Channel] built their obstacle climbing rover. Video after the break.

Continue reading “Lego Wheels And Tracks Benchmarked For Your Pleasure” →

Two-Player PVC Racing Rig Plays Daytona USA

May 1, 2021 by Zoe Skyforest 9 Comments

SEGA’s Daytona USA is that big orange arcade racing machine you remember from the 90s that still seems to hang on in cinemas and pizza joints worldwide. Its controls may be floaty and physics unrealistic, but it’s probably the one racing game that almost everyone has played at one point or other. [Tom Tilley] decided to build a PVC racing rig for the game during his travels in Thailand.

As a bonus, the lightweight rigs can be broken up and transported easily by scooter.

PVC pipe is used to whip up the frames for the budget simulator, inside which each player sits. Different sizes of PVC pipe and various adapters are used to create a basic steering wheel, to which a potentiometer is attached, while the centering mechanism is simply a rubber band. The pedals are built similarly and fitted with microswitches. The build relies on a cheap USB gamepad that mimics the typical PlayStation Dual Shock design, with the pot and switches wired in place of the existing thumbstick and buttons. A computer running the PC version of Daytona USA is then used to complete the setup, along with a projector for split-screen fun.

It’s certainly not a high-end simulator by any means, but for the price of some pipes and cheap controllers, [Tom] was able to create a two-player racing rig for a fraction of the cost to hire the real arcade machine for a weekend. The kids that playtested the system certainly seemed to have a good time, as well. We’ve seen similar low-tech builds before, too – with impressive results. Video after the break.

Continue reading “Two-Player PVC Racing Rig Plays Daytona USA” →

Could Seven Gamers Play Quake On Just One 1996 SGI Machine?

May 1, 2021 by Zoe Skyforest 46 Comments

[Linus Tech Tips] undertook a fun experiment a few years back. By running multiple virtual machines on a single tower PC with tons of RAM and GPUs, it was possible to let seven gamers play on a single rig at once. [CelGenStudios] found the idea intriguing, and has theorised that the same feat could be possible on mid-1990s Silicon Graphics hardware.

The idea is to use the Origin 2000 server as the base. These didn’t ship with any form of video output or even a keyboard and mouse interface. However, by substituting in the IO6G module from the Onyx2 machine, and SI graphics cards from the Octane, it’s possible to get graphics and input up and running. With multiple graphics cards and a few CAD DUO boards installed via a PCI adapter called the “shoebox”, there’s provisions for up to four separate monitors, keyboards and mice. With all this hardware, it’s theoretically possible for four users to login to the X server running in the IRIX OS on the Origin 2000 machine. Then, it’s a simple matter of firing up four instances of Quake and a dedicated server and you’re up and gaming.

[CelGenStudios] goes so far as exploring the limits of the supercomputer-grade hardware, suggesting that 7 players or more could be possible. Unfortunately, SGI hardware isn’t easy to come by, nor is it cheap, even decades after release — so thus far, the concept remains untested. We’d dearly love to see such a setup happen at QuakeCon or a hacker con, though, so if you pull it off, you know how to call. We note there’s a few Octane 2000s at the Jim Austin Computer Collection, so perhaps they might be the ones to achieve the feat.

In the meantime, check out a practical exploration of the concept on modern hardware with the original [Linus Tech Tips] project. The basic theory is simple – create a hugely powerful PC, with a beefy CPU, plenty of RAM, and one graphics cards for each of the seven players. They run multiple virtual machines and managed to deliver a full 7 player experience running off just one CPU.

Continue reading “Could Seven Gamers Play Quake On Just One 1996 SGI Machine?” →

Modding A Casio W800-H With A Countdown Timer

April 30, 2021 by Zoe Skyforest 29 Comments

Stock, the Casio W800-H wristwatch ships with dual time modes, multiple alarms, and a stopwatch – useful features for some. However, more is possible if you just know where to look. [Ian] decided to dive under the hood and enable a countdown timer feature hidden from the factory.

The hack involves popping open the case of the watch and exposing the back of the main PCB. There, a series of jumpers control various features. [Ian]’s theory is that this allows Casio to save on manufacturing costs by sharing one basic PCB between a variety of watches and enabling features via the jumper selection. With a little solder wick, a jumper pad can be disconnected, enabling the hidden countdown feature. Other features, such as the multiple alarms, can be disabled in the same way with other jumpers, suggesting lower-feature models use this same board too.

It’s a useful trick that means [Ian] now always has a countdown timer on his wrist when he needs it. Excuses for over-boiling the eggs will now be much harder to come by, but we’re sure he can deal. Of course, watch hacks don’t have to be electronic – as this custom transparent case for an Apple Watch demonstrates. Video after the break.

Continue reading “Modding A Casio W800-H With A Countdown Timer” →

An LED Heartbeat Display You Can Wear On Your Sleeve

April 30, 2021 by Zoe Skyforest 3 Comments

There are a few different ways to take a person’s pulse, with varying utility depending on the categories said patient fits in to. [Nitin Nair]’s method doesn’t really have a medical application, but it’s certainly a neat example of what you can do with modern sensors.

The build combines an EmotiBit sensor platform with an Adafruit Feather and accompanying Charlieplexed LED module. The EmotiBit packs a PPG, or photoplethysmogram sensor, otherwise known as a pulse oximeter, which uses optical methods to detect changes in blood volume beneath the skin. From this data, a pulse rate can be derived, and the LEDs flashed with a heart graphic in concert with the rhythm of the wearer’s heart. The benefit of the PPG in the EmotiBit is that it can be worn on the wearer’s arm, or other location with suitable vascularization. This allows the wearer to place the sensor on the arm, and thus wear their heart on their sleeve.

It’s a cool concept, and we’d love to see it neatly packaged with a smoothly animated fade as a sports accessory. It’d be an easy way to signal how fast your heart rate recovers on a run with friends – the device could brag about your fitness for you. Alternatively, if pulse oximetry isn’t enough for you, go ahead and build an ECG instead!

An Attempt At 3D Printing A Hybrid Rocket Engine

April 29, 2021 by Zoe Skyforest 6 Comments

Liquid fuelled engines are throttleable and monstrously powerful, but highly complex. Meanwhile, solid rocket engines are simple and cheap, but once you light them, they’re going full-bore until burnout. Hybrid rocket engines offer perks from both worlds, with simple solid fuel and the ability to throttle down by regulating oxidizer flow. Naturally, [Integza] decided he should try and 3D print one.

The build came about somewhat by accident, as the 3D printed casing of one of [Integza’s] liquid-fuelled rockets continued burning once the fuel was turned off. This prompted the realization that he could 3D print rocket fuel, and simply supply oxygen, creating a hybrid rocket. Thus ensued much experimentation, going so far as to create custom sugar-loaded resin for more power and experimenting with ABS as a potential fuel.

Most of the rockets self-destructed within a few seconds and thrust was minimal, but the basic concept should be a goer. As always, [Integza] is struggling with the thermal limitations of plastics, but we fully expect he’ll one day get to a flight ready engine. His previous experiments show he certainly doesn’t give up. Video after the break.

Continue reading “An Attempt At 3D Printing A Hybrid Rocket Engine” →

Solar And Wind Could Help Support Ethiopia’s Grand Dam Project

April 29, 2021 by Zoe Skyforest 22 Comments

Ethiopia is in the midst of a major nation-building project, constructing the Grand Ethiopian Renaissance Dam (GERD). Upon completion, GERD will become the largest hydropower plant in Africa, providing much needed electricity for the country’s growing population.

The project dams the Blue Nile, a river which later flows into neighbouring Sudan, where it merges with the White Nile and then flows on to Egypt. Like all rivers that flow across political boundaries, concerns have been raised about the equitable management of the water resources to the benefit of those upstream and down. Too much water dammed upstream in GERD could have negative effects on Egyptian agriculture reliant on river flows, for example. Efforts are ongoing to find a peaceful solution that suits all parties. Recently, suggestions have been made to supplement the dam’s power output with solar and wind to minimise disruption to the river’s users.

Continue reading “Solar And Wind Could Help Support Ethiopia’s Grand Dam Project” →