Driving And Old Receipt Printer

June 30, 2011 by Mike Szczys 18 Comments

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

June 30, 2011 by Mike Nathan 9 Comments

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.

Google Android ADK Bluetooth Wireless Communications

June 30, 2011 by Mike Nathan 6 Comments

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.

Giant POV Tube For Light Painting

June 28, 2011 by Mike Nathan 29 Comments

writing_in_the_night_with_the_light_scythe

When you really want your feelings known, we always say that bigger is better. [Gavin Smith, aka The Mechatronics Guy] must come from the same school of thought, because there’s absolutely no mistaking what he is trying to say with his latest project.

Inspired by this WiFi signal painter we featured a while back, the LightScythe is a 2 meter long bar composed of multi-color LED strips that he bought from Adafruit. The light bar is controlled by a Seeduino micro controller, which takes direction from his laptop via a pair of XBee units. Once he generates an image from text with ImageMagic, a Python script is used to match the colors as close as possible to the RGB color space. The image is then converted to raw serial data for playback on the Scythe. When he is ready to go, he triggers his camera to take a 10-15 second exposure, during which he walks across the frame, painting his images with the LightScythe.

We always enjoy seeing creative derivations of previous projects we have covered, and the LightScythe does it well. He actually built a pair of these that can work in concert or independently, which we imagine can make for some pretty awesome pictures.

Be sure to check out his Flickr photostream for more examples of what the LightScythe can do.

Tweeting Bird Feeder Keeps A Picture Record Of All Visitors

June 28, 2011 by Mike Nathan 18 Comments

If you weren’t aware, Adafruit Industries is sponsoring the “Make it Tweet” contest over at Instructables, and this Twitter-enabled bird feeder is [quasiben’s] entry into the competition.

His bird feeder not only sends messages to Twitter, it also sends a picture of each bird to Twitpic. The feeder itself is a standard off the shelf model which has been fitted with a LinkSprite camera. A LilyPad Arduino controls the camera, sending images to his computer via a pair of XBee modules. To detect when a bird has stopped by for something to eat, [quasiben] used an infrared LED and an IR detector. The emitter and detector are positioned at opposing sides of the feeder’s opening, triggering the Arduino to snap a picture whenever the beam is broken. Once the image has been transferred to his computer, it is posted to TwitPic.

We’re pretty sure [quasiben] built this Tweeting bird feeder just because he could, but we think it’s a pretty smart idea for people who don’t necessarily have the free time to gaze out the window into their yard. It’s a great way to keep tabs on all your new winged visitors while on the go.

Circuit Design For Multiple UART Connections

June 28, 2011 by Mike Szczys 28 Comments

[Bill Porter] has a tip for designing circuits that have multiple connections to a single microcontroller UART. This stemmed from a review of a friend’s circuit design that used the UART in the project, but also called for an FTDI chip in order to reprogram via USB and a bootloader. Unlike the schematic above, the circuit called for straight connections without any resistors. With that design, a conflict will occur if two devices are connected and attempting to communicate at the same time.

The fix is easy. [Bill] discusses how to prioritize the connection by adding the pair of current limiting resistors seen above. This helps to ensure that damage will not occur, and that the FTDI chip will take precedence. Now the external hardware will not preclude the FTDI chip from accessing and programming via the bootloader. The tutorial is intended for those rolling their own boards out of an Arduino-based prototype, but it will work in any situation where you need multiple connections to a single set of UART pins.

Teamspeak Button Uses Tattoo Machine Foot Switch

June 27, 2011 by Brian Benchoff 11 Comments

As an avid gamer, [Pat Norton] uses Teamspeak with his friends when playing World of Warcraft. [Pat]’s friends were annoyed with the voice-activated option for Teamspeak and the constant squeaking of dog toys, and [Pat] was annoyed with the questionable usability of a push-to-talk key. Dissatisfied with his options, [Pat] built footswitch-controlled teamspeak button using a Teensyduino and a broken tattoo machine foot switch.

The Teensyduino is an incredibly small Arduino compatible board that was perfect for this project. Since the teensyduino can operate as a USB Human Interface Device, it’s very easy to have the board appear as another keyboard to the computer. After borrowing some code from the hardware button of a DIY photobooth, [Pat] hooked up the foot switch to two pins of the board. From there, it was very to adapt the code so the foot switch would act as a third ‘Control’ button. The results look very professional, like a factory-made game controller. We’ve seen a few foot switch keyboard devices before, and while this probably isn’t the most efficient way to have a foot switch button control something on a computer, it’s certainly the smallest we’ve seen.