A Variable Capacitor Made From Junk

July 25, 2013 by Brian Benchoff 28 Comments

cap

[Jezan] decided to introduce his son to electronics by building a small crystal radio. These crystal sets have been around for a long time, and make for a great beginner electronics project, but some of the required parts are a little hard to come by. The most difficult to source part for these radios is a variable capacitor, and not finding one in his parts bin, [Jezan] decided to make his own.

This variable capacitor comes directly from a piece of 1.5 mm thick aluminum sheet. Instead of fancy CNC machines, power tools, or even a pair of tin snips, [Jezan] cut the rotors and stators for his variable capacitors with a pair of scissors. The center hole was punched out with a piece of sharpened pipe, and all the pieces were filed down and sanded for a perfect finish.

Considering the variable caps you can get your hands on are either rare or very old, this looks like a great afternoon project for the budding electronics wizard or radio enthusiast. [Jezan]’s craftsmanship is incredible as well and the finished part looks like it came off an assembly line.

A Video Game With Custom LCD Characters

July 23, 2013 by Brian Benchoff 12 Comments

LCD

[Nakul] wanted to build a video game, and with a few projects worth of Arduino experience decided he could finally attain his goal. He used a character LCD display to make his game, and instead of a text-based adventure, he went with a graphical side scroller.

The display for this space-based side scroller isn’t a graphical display like a CRT or a graphic LCD. Instead, [Nakul] is using the ubiquitous Hitachi HD44780 character LCD display. Normally these are used to display text, but they all have the ability to display custom 5 by 8 pixel characters. The code puts these custom characters – a spaceship, missile, and barrier – into the display’s memory and uses them as the sprites for the video game.

You can grab [Nakul]’s code over on his git or check out the action videos below.

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Electro-permanent Magnets For Quadcopters

July 12, 2013 by Brian Benchoff 40 Comments

electromagnet

Imagine a quadcopter hovering above a payload – a can of beans, perhaps. The ‘copter descends onto the payload, activates an electromagnet, and flies away with a hobo’s dinner. Right now, this is a bit of an impossibility. A normal electromagnet that powerful would consume an amazing amount of power, something quads don’t usually have in abundance. With the OpenGrab project, the dream of a remote-controlled skycrane is within reach, thanks to some very clever applications of magnetics.

The tech behind the OpenGrab is an electro-permanent magnet, basically an electromagnet you can turn on and off, but doesn’t require any power to stay on. OpenGrab was heavily influenced by a PhD thesis aimed at using these devices for self-assembling buildings.

This project had a very successful Kickstarter campaign and has seen some great progress in the project. While beer doesn’t come in steel cans anymore, we can imagine a whole lot of really cool applications for this tech from infuriating electronic puzzles to some very cool remote sensing applications.

Animating A Lamp With The Leap Motion

July 11, 2013 by Brian Benchoff 23 Comments

leap

The Leap Motion is a very cool device, but so far we haven’t seen many applications of interacting with physical devices. [Xavier] wanted to control a cute servo animated desk lamp with his hands, and with the help of a Leap and an Arduino he was able to do just that.

The Leap Motion API has a handy feature that will output all its data over a websocket. It’s a very easy way to transfer hand positions with a minimum amount of overhead, and with just a little bit of Node.js, it’s only two lines of code to connect the Leap to a websocket server.

With the Leap data on a web server, the only thing left to do is pulling it down to an Arduino. Again, [Xavier] used Node.js, this time in the form of johnny five, a Javascript-based Arduino framework. After that, it was a simple matter of mapping the data from the Leap to servo movements in [Xavier]’s Pixar-inspired lamp.

Video of the build below.

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Veronica 6502 Gets Keyboard Input Via USB

July 6, 2013 by Brian Benchoff 8 Comments

PS2

When building a homebrew computer, there are a few milestones that make all the work seem worth it. Of course, seeing the CPU step through address lines on the blinkenlights is near the top, but even more important is being able to type a character on a keyboard and have it show up on a display. [Quinn] didn’t want her Veronica computer to deal with serial terminals or PS/2 keyboards when she typed her first characters in; instead she wanted to read a USB keyboard using 80s-era hardware.

Back in the early days of USB, design specs and keyboard manufacturers included a legacy mode in nearly every USB keyboard ever manufactured. This allows a USB keyboard to work with the ancient PS/2 protocol. [Quinn] tapped into that functionality nearly every PS/2 keyboard has using a 6522 Versatile Interface Adapter. This VIA is in the same family of chips as the venerable 6502 CPU that provides GPIO pins and timers.

[Quinn] connected the keyboard connector tapped for PS/2 input to an ATtiny13. This microcontroller reads the scan codes from the keyboards and sends them to the VIA and the rest of Veronica. It’s quite a bit of work to get to this point, but [Quinn] finally has a computer she can type on, the first step to developing software for her homebrew computer.

A Custom Starcraft Keyboard

July 5, 2013 by Brian Benchoff 6 Comments

keybaord

What do you do if you’re looking for a project, but don’t know what to do? If you’re [gltovar], just look around at your hobbies. He’s been playing Starcraft for a while and finally decided to build a custom Starcraft keyboard.

[gltovar] came across an interesting keyboard layout known as TheCore. Ostensibly, this layout allows the player faster access to the commands most used when playing Starcraft. [gltovar] decided he needed a keyboard specifically designed for TheCore, and set about making one of his own design.

The keyboard matrix is designed around a 1×5 row of keys, each attached to a Teensy microcontroller acting as a USB device. Each of these rows are a separate circuit board, allowing [gltovar] to move the rows up and down ergonomically in a custom enclosure.

It’s everything [gltovar] wanted in a custom keyboard. Whether it improves his Starcraft game is another story entirely, but we’re sure he’s at least having fun.

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Working With Very Cool LCD Modules From Sharp

July 1, 2013 by Brian Benchoff 11 Comments

LCD

Here’s some interesting hardware for you: Sharp came out with a very cool series of LCD displays, gong by the name Sharp Memory LCD. Not only are these displays very low power – on the order of about 5 microAmps to keep the display alive – but some of the smaller displays are reflective, making them eminently readable even in daylight. [Mike] decided he’d take a look at these displays and liked what he found.

While these displays are still pretty new, there are a few breakout boards available to make them accessible to desktop tinkerers. The folks at MakerDyne have a breakout board available and there’s one by kuzyatech over on Tindie.

While these displays are readable in daylight and are extremely low power, don’t expect to display LCD video on them anytime soon. The refresh rate is still fairly slow, but you might be able to get away with simple animations with interlacing and so forth. Still, outside of eink, you’re not going to find a better display in terms of power consumption and daylight readability.

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