Using Pulleys And Weights To Explain Binary Logic Gates

May 30, 2014 by 14 Comments

pulley computer

To demonstrate how computers work, [Alex Gorischek] has made a physical example of how binary logic gates work using pulleys and weights.

For anyone who doesn’t know much about logic gates (Wikipedia), it’s a great lesson in one of the fundamentals of circuitry. Using an old chessboard, eyelets, rings, weights, and string, [Alex] has designed a system that can show off all of the logic gates. This includes: NOT, BUFFER, NAND, AND, OR, NOR, XOR, XNOR. He’s also included a gallery of all his examples here.

The neat thing about this demonstration is it is shown in a way that anyone can understand, heck, it’s also something anyone can play with in order to learn! Stick around after the break and see for yourself.

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Robot-Army IRL Plus A Massive Build Log

May 30, 2014 by 8 Comments

We went to “the dark room” at Maker Faire once more for an interview with [Sarah] of Robot-Army. She and [Mark], who handles software development for the project, were showing off 30 delta robots who know how to dance. Specifically they’re dancing in unison to the movements of another faire-goer. A Kinect sensor monitors those movements and translates them to matching motions from the deltabots.

You should remember seeing this project back in November. Now that the standards for this model have been worked out it was just a matter of sinking about three-weeks into assembling the army. We’re happy to see that the Kickstarter made it to 250% of the goal at the beginning of March, and with that there are even bigger plans. [Sarah] says the goal remains to fill a room with the robots and a we may even see a much larger version some day.

The interview is a bit short since the Robot-Army booth was right next to Arc Attack (hence the noise-cancelling headphones) and we had to try to get in and out between their ear-drum-shattering interruptions. But you can see a ton more about the project in this huge build log post over on Hackaday.io. Also check out the Robot-Army webpage. There’s a nice illustration of their adventures at MFBA and the foam Jolly Wrencher made it into the piece!

The I2C Programmable NFC Tag

May 30, 2014 by 22 Comments

NFCNFC tags are cool, but programming them to do your bidding – whether unlocking your computer, making an Arduino vending machine, or a smart home application – requires using an NFC device to program the tag over the air. An NFC tag programmable with any ‘ol microcontroller would certainly have some interesting applications, and Elecfreaks’ DNFC tag is just the thing to test out these ideas.

While NFC tags are reprogrammable, reprogramming them requires an NFC controller, be that through a dedicated hardware, a phone, or an Arduino shield. The DNFC tag is reprogrammable with a microcontroller with an I2C interface thanks to TI’s RF430CL330H dynamic NFC transponder IC. It still does everything you would expect from a NFC tag – MIFARE compatible. NDEF reading and writing, and everything else – but you can program it through an Arduino, Pi, or any other board with an I2C interface.

TI has an app note on using the chip inside the DNFC for automatic Bluetooth pairing, and Elecfreaks themselves have a few use cases in mind that include putting WiFi credentials on an Arduino board without putting the SSID in code and other Internet of Things™ applications. We’re thinking this is one of those devices that is eminently useful, but for something we just can’t think of off the top of your head. If you’ve got an idea for how to use an I2C programmable NFC tag, drop a note in the comments.

Elecfreaks is doing an Indiegogo campaign for the DNFC, $13 for one. I picked one up, but it’s flexible funding, so buy it or don’t. I don’t care.

Art-O-Matic Is Spirograph’s Young Hip Offspring

May 30, 2014 by 23 Comments

Art-O-Matic automatic spirograph

Some of our more senior experienced readers may remember a toy called the Spirograph. In case you don’t, it’s a geometric shape drawing toy. The way it works is a plastic disc with gear teeth around the perimeter and various holes on its face is spun around a plastic ring with gear teeth on the inside. A pencil is inserted in one of the holes in the disc and, when spun around the inside of the ring, draws different complex shapes called hypotrochoids.

Art-O-Matic automatic Spirograph

This was fun enough to keep a kid entertained for a few minutes. It took a while to make a complete shape and sometimes it was easy to mess up (especially if the hole chosen for the pencil was near the outside of the disc). [Darcy] thought it would be neat to combine the Spirograph’s drawing style with modern technology. The result is called the Art-O-Matic and it draws some pretty wild art, you guessed it, automatically.

Click past the break for more!

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Homemade Alarm System Doesn’t Lack Features

May 30, 2014 by 15 Comments

alarm system

To many of us, our garage (or workshop) is probably one of the most important parts of the house. If a burglar broke in, we’d likely be more worried about our tools! [Ron Czapala] decided he needed an alarm system in his garage to keep his stuff safe, so he decided to build one from scratch.

The system makes use of a Parallax 4×4 keypad membrane, a MCP23008 port expander, a Parallax Propeller, a LCD screen, and a few switches to represent future magnetic reed switches located in the door and window.

Using circular buffers, the propeller has several states for monitoring the garage.

  • Not armed — ignore all sensors
  • Armed — system will react to changes in the sensors
  • Exit delay — system has been armed, 45 second countdown has begun to allow you to exit the garage
  • Window trigger — if the window is opened, the alarm will go off immediately (siren and strobe light)
  • Door trigger — alarm will go off in 60 seconds if correct code has not been entered on the keypad

For a complete demonstration, check out the following video where [Ron] explains it all!

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Kindle thermometer

Kindle Gets Downgraded To An Expensive Thermostat

May 29, 2014 by 14 Comments

E-readers are awesome, don’t get us wrong — but if you have an old one collecting dust, why not use it for something? [John] decided to hack his old Kindle  to act like a thermometer!

The Kindle’s Linux OS is re-purposed to use the Freescale CPU’s internal temperature sensor as a thermometer — since it’s not doing anything most the time, it should be relatively accurate of the ambient temperature.

Unlike some of [John’s] earlier hacks, this one is completely self-contained and reversible. In fact, it’s just a few scripts that check the temperature every minute and then display it in large digits on the screen. The buttons allow you to convert units or reverse boot to the original Kindle software. It can even graph the recent temperature! It makes for a very easy to read outdoor thermometer.

And not to waste all of its hardware features, [John] also set it up to act as a web server, sending the temperature data via port 8014.

You could also take it a step further and have a full weather station, in a nice wooden frame.

Papilio Duo: FPGA, Logic Analyzer, Debugger, And Arduino Compatible

May 29, 2014 by 22 Comments

Back

It’s been a while since we’ve seen some new boards that combine an FPGA and an Arduino, so naturally the state of the art is a little bit behind. The latest from [Jack Gassett], the Papilio Duo, aims to change that by addressing all the complaints of the original Papilio and adding some neat, modern features that you would expect on a board designed in 2014.

On board the Duo is an ATMega32u4, the same chip used in the Arduino Leonardo, allowing for easy integration with your standard Arduino projects. The top of the board is where the real money is. There’s a Spartan 6 FPGA with 9k logic cells, enough to run emulate some of the classic computers of yore, including the famous SID chip, Yamaha YM2149, and the Atari POKEY (!).  With host and device USB, 512k or 2M of SRAM, and an ADC on the FPGA inputs, this board should be able to handle just about everything you would want to throw at it. There’s even a breakout for HDMI on the bottom.

There are a few interesting software features of the Duo, including a full debugger for the ATMega chip, thanks to an emulated Atmel JTAG ICE MKII. Yes, an Arduino-compatible board finally has a real debugger. The FPGA can also implement a 32 channel logic analyzer, making this not only an extremely powerful dev board, but also a useful tool to keep around the workbench.