Jacob’s Ladder Makes Itself At Home In A Floppy Disk Box

March 30, 2011 by Mike Szczys 14 Comments

[Plasanator] adds a bit of safety to his Jacob’s Ladder by housing it in a familiar enclosure. It doesn’t take very many components to make one of these, but to get the high voltage you’ll need some type of coil. He’s using one from the electrical system of an old car, then building around it with a big 15mf 220V capacitor, a dimmer switch normally used in household wiring, terminal blocks, and some braising rod or coat hanger for the spark to traverse.

The video after the break shows this in operations, and we’d agree with [Plasanator] that this is a wonderful addition to your Halloween decor. Of course you want to keep fingers away from the dangerous bits and that’s where the enclosure and key lock come into play. Were not sure what he made the upright cylinder from, but the base is a blast from the past. Remember when one of those used to sit proudly on every desk as a tribute to how important the information you had on had really was?

Don’t want to play with high voltage like this? You can build a fake using EL wire.

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SMS Gateway Lets You Twitter By Text Message

March 30, 2011 by Mike Szczys 27 Comments

[GuySoft] threw together a cellphone-based SMS gateway that allows him to push text messages to Twitter. Once up and running, it can be used by multiple people, either with shared or individual Twitter accounts. At its core, this setup uses the cellphone as a tethered modem on a Linux box. The open source software package, Gammu SMSD, provides hardware hooks for phones running in modem mode. The package is already in the Ubuntu repositories but it runs cross-platform and can be downloaded from the project site. This gave [GuySoft] the ability to script a framework that checks for received SMS messages, compares the incoming phone number for a match on a saved list, then pushes the message from a confirmed number to Twitter via their API.

A web interface is used to register new numbers and associate them with Twitter accounts. On the back-end, [GuySoft’s] own Python script handles the translation of the message. You can download all of the code, and get more insight on setup from the readme file, over at the GitHub repository.

Designing A Controllable RGB LED Driver Board

March 30, 2011 by Mike Szczys 16 Comments

[Paul] wrote in to tell us about this LED driver board he’s been working on with a few friends. The collaborators had been unhappy with the Lumens per Watt ratings (or lack of a rating) on low powered LEDs and set out to find a better solution. They picked up the beefy ASMT-MT00 which houses all three diodes in one package, with all the pins on one side of the surface mount package, a heat dissipating tab on the other side, and pushed 30 Lumens per Watt. With that in hand they set out to design a host board for the blindingly bright light.

The board includes a heat sink on the underside. To drive the LEDs [Paul] sourced an LM3407 constant current driver. The manufacture recommends using one of these chips for each of the colors in the LED package. [Paul] built a circuit that allows him to route power around each LED, making the system work with just one low-side driver. From there, an ATtiny2313 provides addressable control via the RS485 protocol. Screw terminals on either end of the PCB allow this to be chained along with other modules, and they’ve already worked out a basic PureData program that will be able to address multiple boards once they finish manufacturing them.

Headphones Use Standard-sized But Proprietary Rechargeable Batteries

March 30, 2011 by Mike Szczys 83 Comments

Here’s something we haven’t run across before. We’re familiar with proprietary battery shapes (we’re looking at you, digital camera manufacturers), or custom recharge connections (look of death directed toward cellphone manufacturers), but using electrical tricks to force AAA brand loyalty is a new one. It seems that’s exactly what is happening with [OiD’s] wireless headphones which were manufactured by Phillips.

The headphones take AAA sized batteries and can use either disposable or rechargeable varieties. There is a warning label advising that only Phillips brand rechargeables should be used, and sure enough, if you try a different brand the performance suffers both in charging time and in battery life. The original batteries are labelled as Nickel Metal Hydride at 1.2V and 550 mAh, which falls within common specs. But [OiD] noticed that there is an extra conductor in the battery compartment that makes contact with the sides of the battery case. Further inspection reveals that a reverse-biased diode makes contact through this conductor with a portion of the battery which has not been painted. This is not true with other brands, allowing the circuit to distinguish between OEM and replacements.

[OiD] shorted out that connection and immediately saw a performance boost from his replacement batteries. It’s hard to know exactly what’s going on here without a full schematic for the circuit, but we’d love to hear your speculation on this setup in the comments. Is this a low tech version of the identity chips that camera batteries sometimes hide?

Robotic Bird Flaps Away Last Bits Of Privacy

March 30, 2011 by Mike Szczys 45 Comments

This really gives a lifelike look to the eye in the sky. In case you were worried that every part of your life wasn’t being recorded by a surveillance camera, the Festo Bionic Learning Network has come up with a drone that will be hard to discern from the wildlife.

Watch the video after the break. We’re not 100% certain that it’s not fake, but it looks real enough (the mark of a truly amazing design). You’ll see the robo-bird flapping away both from a fixed point on the ground, and from a camera view behind the head of the device. It propels itself both by flapping and rotating the wings and is capable of taking off, flying, and landing autonomously.

It’s bigger than the hummingbird drone that was developed for DARPA, but we think that it sticks out less when caught at a glance. No word on the intended use for the device, but we’re sure that some of you are enjoying the nostalgia of the mechanical owl from Clash of the Titans, and that’s why we want one.

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Propeller-Android Communications Using Debug Mode

March 29, 2011 by Mike Szczys 17 Comments

Here’s a new way to connect an Android phone and a Propeller microcontroller. It’s called the PropBridge and uses a very simple circuit with a voltage regulator, a couple of transistors, and a few resistors. The trick to this method lies in creative use of software features that already exist on Android hardware, the Android Debug Bridge (ADB). The ADB was added with development in mind, but since it provides low-level control of certain parts of these devices it was just waiting to be incorporated into a hack.

The Propeller itself uses firmware to make Android think it is one of two different externally connected hardware devices. It can act like a PC running the ADB client or it can mimic a TCP connection. There’s still plenty of room on the uC to add your own firmware, and the majority of the I/O pins are unneeded for the basic connection. Check out the video after the break for a quick overview of the system.

If you need a little help with Android programming before you’re able to use this in your own projects, check out our Android development series.

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Quadcopter Pair Plays Table Tennis Without The Table

March 29, 2011 by Mike Szczys 22 Comments

This pair of quad-rotor helicopters does a better job of keeping a ping-pong ball in the air than we could. The two flying drones are performing inside of the flying machine arena, a 1000 cubic meter indoor space surrounded by nets with a foam-padded floor. This makes for a prototype-friendly space, protecting the copters from hard landings and the experimenters from the maiming that might accompany a runaway robot.

This project is headed by researcher [Raffaello D’Andrea]. Previously, we’ve seen his work on a distributed flight array. This time around he’s not working with configurable modules, but completely separate units. Don’t miss the video after the break to see several iterations used to keep a ball in the air. Each bot has the head of a tennis racket mounted at its center. Throw a ball at them and they’ll to what they can to prevent it touching the ground.

While we’re on the topic, we caught a story on NPR about hobby drones. Sounds like their growing popularity has caught the attention of the non-hacker community and restrictions might be on the way. So what are you waiting for? Get out there and make your own flyer while it’s still the wild-west of personal drones.

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