Self-balancing Arduino Does It Without An IMU

September 26, 2013 by Mike Szczys 15 Comments

The miniscule size of this self-balancing robot makes it a cool project. It actually uses the motor and wheels from a small toy car. But when you look into how the balancing act is performed it gets way more interesting. The larger versions of this trick pretty much all use Inertial Measurement Units (IMUs) which are usually made up of an accelerometer and a gyroscopic sensor. This has neither.

The black PCB seen to the right of the robot is an IR reflectance sensor. It shines an IR led at the floor and picks up what reflects back. [Sean] added this hack because the gyro sensor he ordered hasn’t arrived yet. The board has a trimpot which is used to adjust the sensitivity. You have to tweak it until it stands on its own. See for yourself after the break.

Self balancing robot builds are a great way to teach yourself about Proportional-Integral-Derivate (PID) algorithms used in a lot of these projects.

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Crowdsourcing Plastic Model Kits

September 25, 2013 by Brian Benchoff 8 Comments

laser

Flexiscale, the company that crowdsources and crowdfunds model kits, made a showing at the World Maker Faire. We’ve seen their work before, but this time we got to touch base with [Chris Thorpe] and get a handle on the future of user-requested model kits.

Right now there are over one hundred proposals for what Flexiscale should do next. They’re mostly narrow gauge railroad locomotives and rolling stock, but [Chris] tells me they’re looking to branch out into larger projects including American locomotives as well as planes, ships, and buildings. This is a really, really cool project, and if you’re into models at all, you should at least be aware of what Flexiscale is trying to do.

If you have an idea of what Flexiscale should do next, write up a proposal. I made one for the PRR GG1 electric locomotive, and if enough people support it, [Chris] will scan an engine and make a kit.

World Maker Faire: 3D Printed Tower Defense

September 23, 2013 by Brian Benchoff 12 Comments

Seej

Going to the World Maker Faire isn’t all fun and games; sometimes you have to suck it up, pay $130 in cab fare, buy $7 Heinekens, and crash the super not-so-secret after party. While the company was fantastic, one of the more exciting interactions was [Jim Rodda]’s Seej, a tower-defense-ish game constructed entirely of 3D printed weapons, flags, and blocks.

The goal of the game is simple: Each player gets a Seej engine, some blocks, a few pennies, and three flags. The first person to topple all three flags with ballistic pennies is declared the winner. The Seej engines aren’t just limited to the red and black catapults shown above; there are plans for a ballista available, and we’re sure someone will add a 3D printed trebuchet the the arsenal at some point. We’ve seen at least one example floating around the web.

In all honesty, this game is really fun and well worth the frustration experienced by a pitiable bartender who I hope was tipped well for the night.

Screaming Fast RC Hovercraft

September 4, 2013 by Marsh 19 Comments

Of all the homemade RC Hovercraft floating around out there, this build is not only one of the better looking: it’s also unexpectedly quick. [ScratchBuiltAircraft] sourced foam board from the local dollar store to construct the hovercraft’s body and a heavy-duty garbage bag with a hole cut in the center for the skirt. Air reaches the skirt area from the hovercraft’s EDF (Electric Duct Fan — the big one on the back) which pumps the air through a rectangular hole in the base.

A servo mounted behind the fan controls the rudders, while the rest of the electronics and the battery are cleanly tucked away beneath foam body pieces. We’re not sure what kind of top speed the Turnigy motor provides, but it’s probably impressive assuming it can keep from flipping over. Watch it blast off with a bit too much lift in the video below.

For something a bit slower, there’s always the solar powered hovercraft from earlier this summer.

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Obstacle Avoiding LEGO Rover Uses CDs For Wheels

September 1, 2013 by Mike Szczys 3 Comments

lego-rover

This rover built by [Sath02] is a great example that you don’t have to be a mechanical engineering wizard to get into robotics. He used LEGO pieces to help ease the difficulty of getting a rover up and running.

In this case the use of LEGO is strictly structural. The electronics are not the NXT parts you would expect to see when working with these popular toy blocks. Instead he’s put the Arduino Palm Plus into service. It’s an Arduino board that has rows of holes at either end to make it LEGO compatible. It also carries an LM293D motor controller and [Sath02] added an XBee module for wireless control.

At the top of the assembly is an IR distance sensor which is used for obstacle avoidance. You may not be interested in building and exact replica, but the techniques he uses for attaching the distance sensor, CD wheels, and fabricating the rest of the rover are good examples if you take on a LEGO build in the future.

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24-hour Hackathon Produces Respectable Accelerometer Labyrinth

August 29, 2013 by Mike Szczys 12 Comments

hackathon-labyrinth

We’re not sure if this was some type of corporate team building, but if it was sign us up for the next one. [Filipp], [Saluka], and [Michael] participated in a recent 24-hour hackathon hosted by Microsoft. They whipped up this labyrinth game controlled by a Nexus 4 Android phone.

This thing looks so well crafted we’re shocked that it’s a 24-hour build. Just putting together the walls of a maze that size takes some time. They then mounted it in a gimbaled frame which tilts the using servos. Check out the demo video below to get a look at the underpinnings. There are several elastic bands connecting the base to the maze. These act as shock absorbers to help keep the movement smooth and to prevent any oscillations from the frame flexing. For us this is an important design element that we’ll keep in mind (just in case we need to win another competition by designing a labyrinth).

An Arduino controls the servos, using Bluetooth to communicate with the phone. The team mentions some filtering used to help make the user experience more natural but we didn’t see many details on this aspect of the hack.

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Milled Water Bottle Rocket Launcher Pushes Plastic Containers To Their Limit

August 27, 2013 by Mike Szczys 31 Comments

water-bottle-rocket-launcher

Building this launcher is simple if you already have a mill. It does a remarkable job of pressurizing and launching soda bottles which are partially filled with water. The main component of this is a triple-gasket stopper with a quick release.

The problem with a lot of these water bottle rocket projects is that they leak where the bottle meets the launcher. In most cases this is a good thing as it’s almost impossible to build up enough pressure to cause the bottle to fail. This system has no such built-in safety mechanism, which is why the test launch below is conducted from a safe distance. After seating the partially filled bottle on the launch platform it’s pressurized to around 100 PSI at which point a yank on the string lets it fly.

Most of the time we look on these as casual projects. But we figure this one is much more suited for a rocket club or hackerspace event.

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