Relay Calculator

April 22, 2011 by Kevin Dady 6 Comments

Calculators are a handy tool to have around in just about every application. We often take them for granted today, but even when I was a kid they were still sort of expensive devices that you put thought into buying. Illustrating just how far we have come is this awesome Relay Calculator brought to us by [Team 619].

Featuring an optical slider input system, the user can select any two 4 bit numbers and can add or subtract them. Logic is carried out by a couple handfuls of relays setup to be AND, OR, or XOR gates, which are then linked together to build adders.

Output is in binary as well, in the form of lights, though we cant really tell if those are some form of tubes or if they are just rods lit on end. Either way if you require a lot of nibble math and want a conversation starter this suits the bill quite niceley. Otherwise you can keep hooking up more and more relays and maybe one day make your own relay computer.

Join us after the break for a quick video!

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Beat707 Takes It’s Cue From A Vintage Drum Machine

April 22, 2011 by Brian Benchoff 19 Comments

We always like musical hacks at hackaday, so we were pleased to see the team at [Beat707] come out with their Beat707 MIDI groove box.

The Beat707 takes it’s inspiration from the venerable Roland TR-707. Like the Roland, the Beat707 can save songs and has MIDI In and Out. Unlike the TR-707, the Beat707 doesn’t have an audio out – it’s purely MIDI based. Don’t think of that as a drawback, though. Just connect the Beat707 to your favorite softsynth and start jamming out.

The Roland TR-707 was heavily used by acts like the Chemical Brothers, Aphex Twin, and the Cocteau Twins. Because of this history, the popularity of the TR-707 has exploded over the past few years, and getting a hold of a real TR-707 has been an expensive proposition. While rebuilds of vintage synths like [Ladyada]’s TB-303 clone, the x0xb0x have been around for a while, we’re pleased that more projects are paying their dues to the great music machines of the 1980s. Do any hackaday readers want to tackle an 808 or 909 for their next project?

Video of the Beat707 after the break.

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Rule Your Furnace With This Network-enabled Thermostat

April 22, 2011 by Mike Nathan 13 Comments

diy_thermostat

Adafruit forum member [Stephanie] embarked on a mission to replace the thermostat in her home with one that was far more robust and full of electronic goodies.

Her goal was to build a networked thermostat that allowed for 2-way communications between the base station and any other networked device, such as her laptop or iPhone. She wanted to not only be able to monitor her furnace and air conditioning systems remotely, but to control the units from afar as well.

The brains of the thermostat have changed throughout the project, becoming simpler as time went on. It is now controlled with just an ATMega328 mounted to the back of an LCD display with a Wiznet network module where an Adafruit Ethernet shield used to reside. The thermostat shows the current temperature, set temperature, and time on the front mounted LCD, the latter of which is provided by a Chronodot module. It also has an on board LED that can be seen from afar, indicating whether the heat or air conditioning is running,

Right now the thermostat can be controlled at the unit itself, or remotely using a Telnet session. [Stephanie] is currently happy with the setup, but future plans include creating an iPad application to provide a more user-friendly interface.

If you are interested in learning more, or building one yourself, be sure to swing by her blog for a far more in-depth look at the build process.

PCB Milling Tutorial

April 22, 2011 by Mike Szczys 26 Comments

[Juan Jose Chong] put together a set of videos and a PDF guide to milling printed circuit boards. You’ll find the pair of videos, totaling about twenty-two minutes, embedded after the break. In them, [Jaun] details the techniques used by the IEEE chapter at Texas Tech University to mill PCBs instead of using the traditional method of etching them. We’ve long been a fan of milled PCBs and often dream about the day we can retire the old iron we use for the toner transfer method.

In the tutorial, IsoPro is the software used to control the mill. The CAM files from a PCB design program are imported – they can come from many different programs including EagleCAD. A few setup steps let the operator configure the resolution necessary to mill the correct tolerance and from there the paths that outline each trace are calculated in software. In order to facilitate double-sided boards a reference hole is drilled in the copper clad board to accept a post on the mill table. Tape down the substrate with some foil tape, set the depth of the end mill bit, and let the machine do its thing. [Juan’s] video illustrates how quickly this can produce a rather complicated board, finishing in around 20 minutes.

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MindWave Is Developer (read: Hacker) Friendly Mind Control

April 22, 2011 by Mike Szczys 3 Comments

Here’s a setup to control a servo motor with your mind. [Danny Bertner] made this project happen by interfacing a MindWave headset with an Arduino. You might wonder what’s the big deal about that since we’ve covered quite a few mind control hacks that work this way? So far, the majority of those hacks used the Mindflex toy (to be fair there were several using the Force Trainer as well), which depends on a chip made by the company that is responsible for the MindWave. Both the Mindflex and the Force Trainer were reverse engineered to access the stream of data coming in from the EEG sensors. But NeuroSky is embracing the urge to mess with their products by offering developer tools.

[Danny] took advantage of these resources, using the comany’s own guide to interfacing with an Arduino (PDF). The quick clip after the break shows his finished project, grabbing data from the USB dongle that comes with the headset, converting it to the necessary levels for the Arduino, then processing the signals for display on and LED bar graph.

We can’t help but chuckle about the warranty-voiding disclaimer at the top of the PDF guide.

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Laser Tripwire Water Balloon Prank

April 21, 2011 by Mike Nathan 8 Comments

laser_tripwire_prank

Even though it’s a bit late for April Fool’s jokes, [Ameres] wrote in to share a project guaranteed to catch your friends (or enemies) by surprise.

Like us, he had some old CD-ROM drives sitting around and thought that there must be some way to put them to good use. He gutted one, saving the laser’s carrier unit for use as his mechanical trigger. He placed the unit above a doorway, soldered a pin on to the end of the laser carrier, and positioned a water balloon at the end of the CD-ROM’s rails. The laser carrier’s motor was then connected to a photocell located about half way down the side of the door.

He mounted a laser on the far side of the door, which is pointed at the photocell. Once the laser beam is broken, the CD-ROM motor is actuated, popping the balloon over the unsuspecting victim.

It’s not the most high-tech prank out there, but how high tech does a water prank need to be? We just wonder how easy it would be to attach one of these things to our cube at work…

Have any ideas as to how he can make a bigger splash with his friends? Share them with us in the comments.

Measuring The ~10 Kiloamp Output Of A Large Capacitor Bank

April 21, 2011 by Mike Szczys 22 Comments

[Norman] put together a rather impressive 22,500 uF capacitor bank. In addition to find things to torture with the strong magnetic field generated by a sudden discharge, he’d like to measure the current pushed from the device. He’s found a way to do this using a digital storage oscilloscope. To protect the oscilloscope [Norman] built his own interface box that includes a 50x voltage divider, and interfaces a current sensor called a Rogowski coil. When it comes time to run the experiment, he turns the safety lock-out key on the bank charger, then discharges the stored potential with the flip of a switch.

Take a look at the video after the break to see soda cans and hard drive platters mangled by the device. The oscilloscope measures the output near 10 kA, giving [Norman] the data he set out to capture. He’s entered this project into the Tektronix contest where it’ll compete with the piano tuner and laser light show tester just to name a few.

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