arduino

2886 Articles

Use The Force, Luke…to Turn Off Your TV

February 22, 2015 by 10 Comments

Have you ever wanted to turn on or off your TV just by thinking about it? We love this hack mainly because it uses an old Star Wars Force Trainer game. You can still buy them for about $40-$80 USD online. This cool little toy was introduced in 2009 and uses a headset with electrodes, and an electroencephalography (EEG) chip. It transmits the EEG data to control a fan that blows air into a tube to “levitate” a ball, all the while being coached on by the voice of Yoda. (Geesh! Kids these days have the best toys!)

[Tinkernut] started by cracking open the headset, where he found the EEG chip made by a company called NeuroSky (talk about a frightening sounding company name). The PCB designer was kind enough to label the Tx/Rx pins on the board, so hooking it up to an Arduino was a snap. After scavenging an IR LED and receiver from an old VCR, the hardware was just about done. After a bit of coding, you can now control your TV by using the force! (Ok, by ‘force’ I mean brainwaves.)  Video after the break.

Note: [Tinkernut’s] blog page should have more information available soon. In the meantime if you can find his Arduino Brain Library on github.

This isn’t the first EEG to TV interface we’ve featured. Way back in 2010 we featured a project that used an Emotiv EPOC EEG headset to turn on and off a TV. But at $400 for the headset, it was a little too expensive for the average Jedi.

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Hardware for a ST4 to USB interface

Cheap USB Control For Your Telescope

February 20, 2015 by 23 Comments

There’s many complex systems for automatically pointing a telescope at an object in the sky, but most of them are too expensive for the amateur astronomer. [Kevin]’s Arduino ST4 interface lets you connect your PC to a reasonably priced motorized telescope mount, without ripping it apart.

The ST4 port is a very basic interface. There’s one pin per direction that the mount can move, and a common pin. This port can be added to just about any motorized mount with some modification to the controller. To connect to an Arduino, a TLP521-4 quad optoisolator is used. This keeps the Arduino and PC fully isolated from the motor circuits. but lets the Arduino take control of the mount.

With the hardware in place, [Kevin] cranked out some software which is available on Google Code. A simple Arduino sketch provides the USB interface, and a custom driver allows the ASCOM Platform to control the mount. Since many astronomy software tools support ASCOM, this allows the mount to be controlled by existing software.

With the interface in place, the mount can be used to find objects (GOTO) and automatically follow them with high accuracy (autoguiding). You can watch the telescope move on its own after the break.

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Blackboard Digitization For Under $40

February 17, 2015 by 22 Comments

Digital White/Black Boards or “Smart Boards” are very useful in modern classrooms, but their high cost often makes it difficult to convince administrators from loosening their purse strings. Cooper Union’s 2nd annual HackCooper event in New York wanted students to design and build hardware and software projects that both solve real problems and spark the imagination. At the 24 hour hackathon, the team of [harrison], [david] and [caleb] decided to put together a low-cost and simple solution to digitizing classroom black board content.

A chalk-holder is attached to two strings, each connected over a pulley to a weight. The weights slide inside PVC pipes at the two sides of the black board. Ultrasonic sensors at the bottom of each tube measure the distance to the weights. The weights sit in static equilibrium, so they serve the purpose of keeping the string taut without negatively interfering with the writer.

With a couple of calibration points to measure the extent of displacement of each weight, board width can be determined, making it easy to adapt to different sizes of boards. Once calibrated, the system can determine position of the chalk over the board based on some trigonometrical calculations. Since they had just 24 hours to hack the system together, they had to use a hand operated radio with a couple of buttons to provide user control. Pressing the “Write” button starts transmitting chalk movements to the digital screen. A second button on the radio remote serves to “Erase” the digital screen. After receiving the chalk position data, they had to do a fair amount of processing to eliminate noise and smooth out the writing on the digital screen.

A server allows the whole class to receive the chalk board data in real time. After each “Erase” command, the chalk board state is saved and logged on the server, thus allowing previous content to be viewed or downloaded. If only text is written, optical character recognition can be used to further digitize the content.

What makes the project really useful is the low cost. The sensors cost a dollar. The other parts – PVC pipe, weights/pulleys, Arduino and the Radio key fob – were all bought for under 40 dollars. For some additional cost (and maybe more time in their case) they could have automated the detection of when the chalk was actually doing the writing. The team have made their code available on Github. For a Chalk board at the other end of the cost spectrum, check this one out. Video below.

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Automatic Garage Door Opener Works For Your Cat

February 17, 2015 by 14 Comments

Using an Arduino or Raspberry Pi to perform a task in the real world is certainly a project we’ve seen here before, and certainly most of these projects help to make up the nebulous “Internet of Things” that’s all the rage these days. Once in a while though, a project comes along that really catches our eye, as is the case with [Jamie’s] meticulously documented automatic garage door opener.

This garage door opener uses an ATMega328 to connect the internet to the garage door. A reed switch is installed which lets the device sense the position of the door, which is relayed back to the internet. [Jamie] wrote an Android app that can open and close the door and give the user the information on the door’s status. One really interesting feature is the ability to “crack” the garage door. This is done by triggering the garage door opener twice with a delay in between. From the video after the break we’d say this is how [Jamie’s] cat gets in and out.

We love seeing projects that are extremely well documented so that anyone who wants to make one can easily figure out how. Internet-connected garage door openers have been featured in other unique ways before too, but we’ve also seen ways to automatically open blinds or chicken coops!

Non-Arduino Powered By A Piece Of Computing History

February 17, 2015 by 39 Comments

Sometimes it is a blessing to have some spare time on your hands, specially if you are a hacker with lots of ideas and skill to bring them to life. [Matt] was lucky enough to have all of that and recently completed an ambitious project 8 months in the making – a Non-Arduino powered by the giant of computing history – Intel’s 8086 processor. Luckily, [Matt] provides a link to describe what Non-Arduino actually means; it’s a board that is shield-compatible, but not Arduino IDE compatible.

He was driven by a desire to build a single board computer in the old style, specifically, one with a traditional local bus. In the early days, a System Development Kit for Intel’s emerging range of  microprocessors would have involved a fair bit of discrete hardware, and software tools which were not all too easy to use.

Back in his den, [Matt] was grappling with his own set of challenges. The 8086 is a microprocessor, not a microcontroller like the AVR, so the software side of things are quite different. He quickly found himself locking horns with complex concepts such as assembly bootstrapping routines, linker scripts, code relocation, memory maps, vectors and so on. The hardware side of things was also difficult. But his goal was learning so he did not take any short cuts along the way.

[Matt] documented his project in detail, listing out the various microprocessors that run on his 8OD board, describing the software that makes it all run, linking to the schematics and source code. There’s also an interesting section on running Soviet era (USSR) microprocessor clones on the 8OD. He is still contemplating if it is worthwhile building this board in quantities, considering it uses some not so easy to source parts. If you are interested in contributing to the project, you could get lucky. [Matt] has a few spares of the prototypes which he is willing to loan out to anyone who can can convince him that they could add some value to the project.

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GPS Clock Hat

Hat-Mounted Clock Requires Mirror For Wearer To Tell Time

February 14, 2015 by 13 Comments

[gfish] was planning on attending Burning Man and wanted to make something unique (and useful) to wear. He decided on a hat/clock hybrid. Just slapping a clock on a hat would be too easy, though. [gfish] wanted his hat to change time zones both via manual switches or physical location.

On the front of the hat there are 2 hands, as most clocks have. Each one is attached to one of two concentric shafts that run to the back of the hat. Each hand is individually controlled by an RC vehicle servo. Those of you familiar with RC servos know that a servos’ max rotation is about 180 degrees and is certainly not enough for a full revolution required by the clock. To fix this, there is a 3:1 gear set that allows a 120 degree rotation of the servo to move the clock hand a full 360 degrees. With this method, each hand can’t move past 12 and instead has to quickly move counter-clockwise to get where it needs to be in order to again start its journey around the clock face.

Mounted inside the hat there is an Arduino that controls the clock, a GPS shield to determine location and an RTC to maintain accurate time. Mounted on the side of the hat is a control panel that contains an overall on/off switch as well as a rotary switch for selecting a specific timezone or for engaging GPS mode. The whole thing is powered by a 9 volt battery.

If you like unnecessarily complicated top hats, check out this WiFi enabled message displaying one.

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Bill’s Arduino

February 13, 2015 by 10 Comments

Pokemon is a great game by itself, but when you realize that not all of the ‘mon are available in one game, trading is required for completion, and some pokemon aren’t available without either hacking or going to a Toys ‘R Us in 1997, you start to see how insidious this game can be. Figuring he could finally complete the game with an Arduino, [Pepijn] decided to build a pokemon storage system.

This build was inspired by an earlier post that also spoofed trades. Instead of building this project around a high-power micro, [Pepijn] decided to use an Arduino. The protocol Game Boys use to communicate with each other is extremely well documented, although that’s only half the battle. Each game using the link cable used specialized data structures for transfer, and after grepping through a disassembled Pokemon ROM,  [Pepijn] figured out how everything worked.

The completed hardware keeps one Pokemon in the EEPROM of an Arduino. It’s not very fast if you want to catch all 151 Pokemon in the Gen 1 games, but any way you look at it, you’re going to be catching a lot of Magikarp anyway.