Arduino Video Over 2 Wires For Under $50: Mesa-Video

September 1, 2015 by 60 Comments

If you want video support on your project, you might start from a device like a Raspberry Pi that comes with it built in. [Kevinhub88] doesn’t accept such compromises, so he and his Black Mesa Labs have come up with a whole new way to add video support to devices like the Arduino and other cheap controllers. This project is called Mesa-Video, and it can add digital video at a resolution of up to 800 by 600 pixels to any device that has a single serial output.

The video is created by an FT813, a low cost GPU from FTDI that offers a surprising amount of video oomph from a cheap, low power chip (he has demoed it running from a lemon battery), meaning that he is hoping to be able to sell the Mesa-Video for under $50.

UPDATE: [KevinHub88] let us know that he didn’t actually power the device from a lemon battery, as you would need a lot of lemons to make 50mA at 5V. Apologies for any confusion!

However, Mesa-Video is just the beginning. [Kevinhub88] wanted to get around the problem of stacking shields on Arduinos: add more  than one and you get problems. He wanted to create an interface that would be simpler, faster and more open, so he created the Mesa-Bus. This effectively wraps SPI and I2C traffic together over a simple, fast serial connection that doesn’t require much decoding. This means that you can send power and bi-directional data over a handful of wires, and still connect multiple devices at once, swapping them out as required. You could, for instance, do your development work on a PC talking to the prototype devices over Mesa-Bus, them swap the PC out for an Arduino when you have got the first version working in your dev environment. Is the Arduino not cutting it? Because Mesa-Bus is cross-platform and open source, it is easy to swap the Arduino for a Raspberry Pi without having to change your other devices. And, because all the data is going over a simple serial connection in plain text, it is easy to debug.

It’s an ambitious project, and [Kevinhub88] has a way to go: he is currently working on getting his first prototype Mesa-Bus devices up and running, and finalizing the design of the Mesa-Video. But it is an impressive start and we’ll be keeping a close eye on this work. Hopefully he can avoid that head crab problem as well because those things are as itchy as hell.

RC Lawnmower Has No Grass To Cut

August 31, 2015 by 18 Comments

They say laziness and necessity is one of the greatest drives for invention. Whoever said that didn’t think about what happens when inventors are bored. [The Random Mechanic] decided to build himself a remote-controlled lawnmower, despite the terrible drought he’s been having — resulting in literally no grass to cut.

To make the lawn mower remote-controlled, he cobbled together a gas lawn mower, with the remains of an electric wheelchair. This ended up working really well. He’s using an old RC car remote and its two servos to remotely control the original wheel chair’s joystick. Simple, but super effective.

The wheelchair mower is fast, nice and heavy thanks to some lead acid batteries, and very maneuverable with the front wheels being casters. It’s a shame he doesn’t have any grass to cut!

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Custom Threaded Inserts For 3D Printing

August 31, 2015 by 29 Comments

There’s a variety of ways to add threaded holes to 3D printed objects. You can tap a hole, but the plastic isn’t always strong enough. Nut traps work, but aren’t very attractive and can be difficult to get exactly the right size. If you try to enclose them, you have to add a manual step to your printing process, too. You can buy threaded inserts (see video below) but that means some other piece of hardware to have to stock in your shop.

[PeterM13] had a different idea: Cut a piece of threaded stock, put nuts on the end and heat it up to let the nuts reform the plastic. This way the nut traps wind up the perfect size by definition. He used two nuts aligned and secured with thread locker. Then he used a hot air gun to only heat the metal (so as to reduce the chance of deforming the actual part). Once it was hot (about 15 seconds) he pulled the nuts into the open hole, where it melted the plastic which grips the nuts once cooled again.

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Liquid Metal Changes Shape To Tune Antenna

August 31, 2015 by 39 Comments

Antennas can range from a few squiggles on a PCB to a gigantic Yagi on a tower. The basic laws of physics must be obeyed, though, and whatever form the antenna takes it all boils down to a conductor whose length resonates at a specific frequency. What works at one frequency is suboptimal at another, so an adjustable antenna would be a key component of a multi-band device. And a shape-shifting liquid metal antenna is just plain cool.

The first thing that pops into our head when we think of liquid metal is a silvery blob of mercury skittering inside the glass vial salvaged out of an old thermostat. The second image is a stern talking-to by the local HazMat team, so it’s probably best that North Carolina State University researchers [Michael Dickey] and [Jacob Adams] opted for gallium alloys for their experiments. Liquid at room temperature, these alloys have the useful property of oxidizing on contact with air and forming a skin. This allows the researchers to essentially extrude a conductor of any shape. What’s more, they can electrically manipulate the oxidative state of the metal and thereby the surface tension, allowing the conductor to change length on command. Bingo – an adjustable length antenna.

Radio frequency circuits aren’t the only application for gallium alloys. We’ve already seen liquid metal 3D printing with them. But we need to be careful, since controlling the surface tension of liquid metals might also bring us one step closer to this.

Want To Create A FabLab In Your Garage? Start By Joining Your Hackerspace

August 31, 2015 by 58 Comments

For many hardware enthusiasts, it’s hard to stop imagining the possibilities of an almighty fablab in our garage — a glorious suite of machines that can make the widgets of our dreams. Over the years, many of us start to build just that, assembling marvelous workbenches for the rest of us to drool over. The question is: “how do we get there?”

Ok, let’s say we’ve got a blank garage. We might be able to pick up a couple of tools and just “roll with it,” teaching ourselves the basics as we go and learning from our mistakes. With enough endurance, we’ll wake up ten years later and realize that, among the CNC mill, lathe, o-scope, logic analyzer, and the graveyard of projects on the shelves–we’ve made it!

Image Credit: [Rupunzell] on EEVBlog
Image Credit: [Rupunzell] on EEVBlog

“Just rolling with it,” though, can squeeze the last bits of change out of our wallets–not to mention ten years being a long journey while flying solo the whole time.  Hardware costs money. Aimless experimentation, without understanding the space of “what expectations are realistic,” can cost lots of money when things break.

These days, the internet might do a great job of bringing people together with the same interest. But how does it fare in exchanging the technical know-how that’s tied directly to tools of the trade? Can we get the same experience from a chatroom as we might from a few minutes with the local ‘CNC Whisperer’ who can tell us the ins-and-outs about tuning the machine’s PID controllers?

I’d say that we just can’t. “Getting started” in any subject often seems daunting, but we’re at a compounded disadvantage in that the gurus on the forum have some shared implicit knowledge and jargon on the subject that we wont have if we truly are taking our first steps. (Not to fear, though; none of us were born with this stuff!)

Ruling out forums for taking our first baby steps, where can we find the “seasoned gurus” to give us that founding knowledge? It’s unlikely that any coffee shop would house the local hardware guru sippin’ a joe and taking questions. Fear not, though; there are places for hackers to get their sustenance.

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Core Memory For The Hard Core

August 31, 2015 by 57 Comments

[Brek] needed to store 64 bits of data from his GPS to serve as a last-known-position function. This memory must be non-volatile, sticking around when the GPS and power are off. Solutions like using a backup battery or employing a $0.25 EEPROM chip were obviously too pedestrian. [Brek] wanted to store his 64 bits in style and that means hand-wired core memory.

OK, we’re pretty sure that the solution came first, and then [Brek] found a fitting problem that could be solved, but you gotta give him props for a project well executed and well documented.

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