Recreating The Mythbusters Rocket Chevy – At Scale

October 13, 2017 by 9 Comments

If you tuned into the first ever episode of Mythbusters way back when, you’ll remember a certain rocket-powered Chevy Impala. [David Windestal] decided to recreate this – at 1:10 scale.

The car in question is a Hobbyking Desert Fox RC car – normally a four-wheel drive truck which ships ready-to-run, making it a great way to get a project started quickly. Rocket power is provided by the same type of motor used in the Swedish Rocket Knives we’ve covered previously.

Initial testing proves unsuccessful – the car simply tumbles out of control when the rocket is fired. It takes a beating, losing a wheel in the process. Following on from this, a decision is made to cook up a slower burning rocket motor and switch to an asphalt surface for testing. This is much more succesful and the car begins to see some properly high speeds, nearly peeling the tyres off the rim in the process!

It’s a fun concept that could likely be replicated with off-the-shelf rocket motors, too. Throw us your ideas for better rocket powered transports in the comments below.

[Thanks to Heinrich for the tip!]
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Computers That Never Were

October 13, 2017 by 31 Comments

Today it is easier than ever to learn how to program a computer. Everyone has one (and probably has several) and there are tons of resources available. You can even program entirely in your web browser and avoid having to install programming languages and other arcane software. But it wasn’t always like this. In the sixties and seventies, you usually learned to program on computers that didn’t exist. I was recently musing about those computers that were never real and wondering if we are better off now with a computer at every neophyte’s fingertips or if somehow these fictional computing devices were useful in the education process.

Back in the day, almost no one had a computer. Even if you were in the computer business, the chances that you had a computer that was all yours was almost unheard of. In the old days, computers cost money — a lot of money. They required special power and cooling. They needed a platoon of people to operate them. They took up a lot of space. The idea of letting students just run programs to learn was ludicrous.

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A Raspberry Pi Rain Man In The Making

October 13, 2017 by 11 Comments

We see a lot of Raspberry Pis used to play games, but this is something entirely different from the latest RetroPie build. This Raspberry Pi is learning how to read playing cards, with the goal of becoming the ultimate card counting blackjack player.

If [Taxi-guy] hasn’t named his project Rain Man, we humbly suggest that he does so. Because a Pi that can count into a six-deck shoe would be quite a thing, even though it would never be allowed anywhere near a casino. Hurdle number one in counting cards is reading them, and [Taxi-guy] has done a solid job of leveraging the power of OpenCV on a Pi 3 for the task. His description in the video below is very detailed, but the approach is simple: find the cards in a PiCam image of the playing field using a combination of thresholding and contouring. Then, with the cards isolated, compare the rank and suit in the upper left corner of the rotated card image to prototype images to identify the card. The Pi provides enough horsepower to quickly identify an arbitrary number of non-overlapping cards; we assume [Taxi-guy] will have to address overlapping cards and decks that use different fonts at some point.

We’re keen to see this Pi playing blackjack someday. As he’s coding that up, he may want to look at algorithmic approaches to blackjack strategies, and the real odds of beating the house.

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Nematoduino: A Roundworm Neural Model On An Arduino

October 13, 2017 by 13 Comments

When it comes to building a neural network to simulate complex behavior, Arduino isn’t exactly the first platform that springs to mind. But when your goal is to model the behavior of an organism with only a handful of neurons, the constraints presented by an Arduino start to make sense.

It may be the most important non-segmented worm you’ve never heard of, but Caenorhabditis elegans, mercifully abbreviated C. elegans, is an important model organism for neurobiology, having had its entire nervous system mapped in 2012. [Nathan Griffith] used this “connectome” to simulate a subset of the diminutive nematode’s behaviors, specifically movements toward attractants and away from obstacles. Riding atop a small robot chassis, the Arduino sends signals to the motors when the model determines it’s time to fire the virtual worm’s muscles. An ultrasonic sensor stands in for the “nose touch” neurons of the real worm, and when the model is not busy avoiding a touch, it’s actively seeking something to eat using the “chemotaxis” behavior. The model is up on GitHub and [Nathan] hopes it provides an approachable platform for would-be neuroroboticists.

This isn’t the first time someone has modeled the nematode’s connectome in silico, but kudos to [Nathan] for accomplishing it within the constraints an Arduino presents.

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Get Your Smarties Or M&Ms From A Vending Machine

October 12, 2017 by 19 Comments

There are some debates that split the world down the middle. Serious stuff: M&Ms, or Smarties*? Yes, the two chocolate beans may bear a superficial resemblance to each other, but you’re either a Smartie lover, or an M&M lover. No compromises.

[Maximusvo] has sensibly dodged all questions of brand loyalty in his text if not in his images even though it’s obvious what kind of confectionery he’s working with in his candy vending machine. The hard-shell chocolates are loaded into a hopper, from which a colourful cascade is released onto a scale. When the desired weight has been accumulated, it is tipped into a drawer for the hungry recipient.

Behind it all is an Arduino with a motor to release the beans, a load cell to weigh them, and an LCD display to give a status report. A motor vibrates the chute to ensure they move down it, but as can be seen in the video demo below the break it’s not doing an entirely successful job. There is an external buzzer to indicate delivery, and aside from the wooden construction of the machine there are 3D printed parts in the scale.

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It’s A Wall-Mounted Dremel Workstation!

October 12, 2017 by 32 Comments

We’ve all seen Dremel drill presses, but [Tuomas Soikkeli] has created a full-fledged (albeit miniature) workstation using his Dremel as the motor. He has a gnome-sized belt sander with what appear to be skateboard wheels turning the belt, with the Dremel’s toolhead tensioning the belt and turning it as well. There’s a wee table saw, petite lathe, cute router, etc.

The Dremel attaches to the base via the 3/4-to-1/2 threaded end upon which specialized tool ends may be connected, and which DIY add-ons (like this light ring that we published previously) typical connect. Though in truth the threaded end varies in tensile strength from model to model — even the knockoffs have the same end, but is it strong enough to attach to the rig?

We like how [Tuomas] has his rig mounted to the wall. It looks like he has a couple of flexible shaft extenders nearby, allowing the rig to almost serve same role as a shop’s air tools.

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CNC Robot Makes A Move

October 12, 2017 by 30 Comments

Another day, another Kickstarter. While we aren’t often keen on touting products, we are keen on seeing robotics and unusual mechanisms put to use. The Goliath CNC has long since surpassed its $90,000 goal in an effort to put routing robots in workshops everywhere.

Due to their cost and complexity, you often only find omni-wheels on robots scurrying around universities or the benches of robotics hobbyists, but the Goliath makes use of nine wheels configured as three sets in a triangular pattern. This is important as any CNC needs to make compound paths, and for wheeled robots an omni-wheel base is often the best bet for compound 2D translation.

coordinate drawingWhat really caught our eye is the Goliath’s unique positioning system. While most CNC machines have the luxury of end-stops or servomotors capable of precise positional control, the Goliath has two “base sensors” that are tethered to the top of the machine and mounted to the edge of the workpiece. Each sensor connects to the host computer via USB and uses vaguely termed “Radio Frequency technology” that provides a 100Hz update for the machine’s coordinate system. This setup is sure to beat out dead-reckoning for positional awareness, but details are scant on how it precisely operates. We’d love to know more if you’ve used a similar setup for local positioning as this is still a daunting task for indoor robots.

A re-skinned DeWalt 611 router makes for the core of the robot, which is a common option for many a desktop milling machine and other bizarre, mobile CNCs like the Shaper Origin. While we’re certain that traditional computer controlled routers and proper machining centers are here to stay, we certainly wouldn’t mind if the future of digital manufacturing had a few more compact options like these.