New conductive ink allows circuit prototyping with a pen and paper

roller_ball_circuit_drawing

Why spend time etching circuit boards and applying solder masks when all you really need is a rollerball pen and some paper? That’s what University of Illinois professors [Jennifer Lewis and Jennifer Bernhard] were asking when they set off to research the possibility of putting conductive ink into a standard rollerball pen.

The product of their research is a silver nanoparticle-based ink that remains liquid while inside a pen, but dries on contact once it is applied to a porous surface such as paper. Once dry, the ink can be used to conduct electricity just like a copper trace on a circuit board, making on the fly circuit building a breeze.

Previous ink-based circuit construction was typically done using inkjet printers or airbrushing, so removing the extra hardware from the process is a huge step forward. The team even has some news for those people that think the writable ink won’t hold up in the long run. The ink is surprisingly quite resilient to physical manipulation, and they found that it took folding the paper substrate several thousand times before their ink pathways started to fail.

While we know this is no substitute for a nicely etched board, it would be pretty cool to prototype a simple circuit just by drawing out the connections on a piece of paper – we can’t wait to see this come to market.

Androcade is a controller and stand in one

We remember when retro-gaming required a lot of equipment and a serious time commitment to put together a gaming interface. [Scooter2084] proves that we’ve come a long way with this gaming controller built to complement Android hardware.

It’s not immediately obvious from the image above, but the controller itself looks just like Andy the Android. His head is tilted upward and acts as the tablet stand, while his torso hosts the controls. We don’t the arms and legs have a functional use but they are necessary to complete the look.

Traditionally arcade controls have used a hacked gamepad, or dedicated hardware like the MAME cabinets that use iPac control boards. But this rendition interfaces the joystick and four buttons using an Arduino. A Bluetooth shield lets you control the Android device wirelessly, and opens up the possibility to use this as a controller for laptop-based emulators and the like. Don’t miss the video after the break.

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Driving and old receipt printer

It seems like receipt printers are pretty popular as hacking targets lately. Aside from the wasted paper, they cooler than plain old blinking LEDs and we’d image there’s a ton of them floating around out there as advances in technology have prompted retailers to trade in the bulky dinosaurs for slimmer thermal printers. [Philip Hayton] picked up this Epson model at some type of equipment sale and set to work figuring out how to control it.

This unit is addressed via a parallel interface. After assessing the pinout and searching a bit for protocol information [Philip] hooked up his Arduino and printed out a fitting first message that reads: “Hello World”. He’s got a few tricks you can learn from when trying to talk to hardware with which you are not well acquainted.

Need a reason to go out and find your own receipt printer? Check out this paper-based gaming system for some inspiration. Now develop your own paper recycling setup and we can file this one under ‘green hacks‘.

[Thanks Andy]

Tweeting home alarm system

tweeting_home_alarm_system

Instructables user [willnue] wanted to build a DIY Tweeting alarm system from the ground up, but reconsidered after taking a close look at the scope of such a project. He settled on using an off the shelf security system, taking care of the Twitter interface on his own. He bought a GE 45142 Wireless alarm and promptly disassembled it to see how he might retrieve status messages from the unit.

He figured that monitoring the alarm’s LEDs would make the most sense, so he used a bit of Ethernet cable and wired all of the system’s indicators to his Arduino board. He hooked up an Ethernet shield to the Arduino, then wrapped the pair up in a plastic project box that closely matched the look of the security system. Once that was done, he wrote some simple code for the Arduino that monitors each of the alarm system’s six status lights, sending updates to Twitter via the ThingTweet service.

With this system you might not get your status messages in time to foil whoever is carrying off your plasma TV, but at least you will know what to expect once you get home!

If you want to keep tabs on [Will’s] security system to find out the best time to rob him see how things are going, check out his Twitter feed here.

DIY servo activated door lock with capacitive touch keypad

diy_servo_activated_door_lock_capacitive_touch

Since he was a kid [Giorgos Lazaridis] has always loved the idea of having an electronic door locking mechanism, and now that he has the means, he’s decided to construct one for securing the door to his apartment. He calls the project “simple and cheap”, though we’re not sure about the first part. Taking a look at his very detailed build log, you can see that he has invested quite a bit of time and effort into this impressive project.

Buying an off the shelf product was expensive and not a whole lot of fun, so [Giorgos] disassembled his door’s locking mechanism to see how he might be able to actuate the lock electronically himself. With minimal modifications to the lock, he was able to add a servo which reliably opens the it when triggered.

With the mechanical portion of the project out of the way, he spent a great deal of time working on the door’s electronic components, including the PIC-based controller and capacitive keypad. The keypad proved to be a bit of a problem, but after a few revisions he found a design that was both reliable and pleasing to the eye.

The locking mechanism works pretty well, as you can see in the video below, and [Giorgos] is quite pleased with the results.

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Google Android ADK Bluetooth wireless communications

arduino_to_android_ADK_bluetooth_communications

Once the Google ADK was announced, the team over at [ElectFreaks] jumped right in and started experimenting to see what they could do with the new Arduino/Android interface. While the ADK was great for allowing the two devices to interact over a USB connection, they felt that the system would be far better if it allowed for wireless communications instead.

They added a Bluetooth Bee to their Arduino setup and got busy writing an Android application that uses the handset’s built in Bluetooth module to communicate using the ADK. The application configures your phone to act as either a client or server when pairing. This does not affect data flow, as communications are bi-directional, it merely decides which device is placed in discoverable mode.

As you can see in the second part of their post, once the phone and Arduino are connected, it is quite easy to send serial data back and forth between the two devices.

As of right now, their Bluetooth API is in Beta, so things might still be a bit rough around the edges. They do encourage anyone to download and modify the code, which is freely available on their site.

Gigantic 555 footstool

The team at Evil Mad Scientist Laboratories needed a footstool. Obviously not content with buying one, they came across the idea of building a 555 footstool.

After finding some dimension drawings of the 555 timer IC, the team scaled everything up 30 times. While a normal DIP-8 555 is around 0.4 inches long, the footstool is over a foot long and eight inches high. The stool was cut on a CNC mill out of 1/2″ plywood, glued together, and finally panted with the correct date code and the logo of Evil Mad Scientist Labs. The finished product is amazing. We’ve been looking for a nice table, and the idea of an 8 foot long wooden 64-pin Motorola 68000 is pretty appealing.

While there’s no electronics in the footstool, it’s not hard to imagine fabricating some aluminum pins and a hollow body so a huge, functional 555 could be built. It would be possible to use discreet components following the block diagram of the 555 to build a huge Atari Punk Console; the gigantic capacitors are fairly easy to build in any event.

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