Xbee Remote Sensors Tell You When Someone Enters Your Home

December 18, 2011 by Mike Szczys 13 Comments

[Bill Porter] is helping a friend out by designing a simple security system for her home. It relies on Xbee modules to alert a base station when doors are opened, or a pressure mat is stepped on.

The door sensors are quite simple, and you’re probably already familiar with them. One part mounts to the door and has a magnet in it, the mating part mounts to the jamb and has a reed switch that closes a contact when the magnet is in place. The floor mat uses two sheets of conductive material separated by bits of foam. When it is stepped on a circuit is completed and can be sensed by the Xbee as a button press.

These sensors report back to an Arduino base station that has a buzzer and three 8×8 LED modules to scroll a message saying which sensor was tripped. [Bill] does a good job of showing what goes into configuring an Xbee network if you’ve never worked with the hardware before.

You’ll find his demo video after the break.

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Controlling Your Christmas Lights Without Ever Getting Off The Couch

December 18, 2011 by Mike Nathan 11 Comments

remote-xmas-tree-light-switch

14 year-old [Connor Smith] has been busy this holiday season, thinking up ways to improve the lighting situation at home.

A few weeks ago he put together this 3-channel light controller to toggle his parents’ external lights, incorporating an Arduino for control. The Arduino was used to switch the channels on and off at specified intervals in order to create a simple light show on the house’s exterior. Not satisfied with just a few strings of blinky lights, he took his controller back inside for some additional modifications.

He had grown tired of crawling behind the Christmas tree to plug and unplug it every day, and decided to make things easier on himself. He stripped the IR receiver out of an old VCR and interfaced it with the Arduino in his light controller using the IRremote library. After taking a bit of time to decode the values for two infrequently used buttons on his TV remote, he had himself a Christmas tree light switch that he could activate from across the room.

Check out the short video below to see his remote switch in action.

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SMS Remote Start Gives New Life To Your Old Smartphone

December 18, 2011 by Mike Nathan 50 Comments

iphone-sms-remote-start

Hack a Day alum [Will O’Brien] recently upgraded his phone, and was trying to find a use for his old one. He always wanted a remote starter for his Subaru Outback, but wasn’t interested in paying for an off the shelf kit. Since he had this old smartphone kicking around, he thought that it would be the perfect starting point for an SMS-triggered remote start system.

He started off by jailbreaking his phone, which allows him to run some Perl scripts that are used to listen for incoming texts. Using a PodBreakout mini from Sparkfun he connected the phone to an Arduino, which is responsible for triggering the car’s ignition. Now, a simple text message containing the start command and a password can start his car from a anywhere in the world.

While [Will] is quite happy with his setup he already has improvements in mind, including a way for the Arduino to send a message back to him via SMS confirming that the car has been successfully started. He’s thinking about putting together a kit for others looking to add the same functionality to their own car, so be sure to check his site periodically for project updates.

MIDI Synth Arduino Shield

December 17, 2011 by Brian Benchoff 23 Comments

There’s a million and one ways to play around with MIDI and an Arduino. It’s trivial to have a ‘duino spit out a scale to a MIDI keyboard, or even respond to SysEx messages to change a lighting or effects rig. There’s one thing that has eluded MIDI-duino builders, though: implementing a MIDI synthesizer with a DIY shield. It’s a good thing, then, that [Keith] put up a Kickstarter for his AvecSynth project.

[Keith]’s AvecSynth is based around the Dream.fr SAM2195 single chip MIDI synthesizer. It’s a neat little IC that takes in MIDI messages from a sequencer or keyboard and spits out stereo audio. The AvecSynth takes this IC and puts it in a standard Arduino-sized package so building a gigantic light-up, foot-operated piano is now well within the purview of the weekend solder junkie.

While the SAM2195 and AvecSynth doesn’t have fancy subtractive or FM synthesis, it does have the full set of 128 voices in the General MIDI spec. It’s a great project to play around with MIDI, and the price for the DIY kit is right up our alley.

EDIT: [Keith] changed the $20 reward for his Kickstarter to PCB or two SAM2195 chips

CheerLights: Synchronizing Christmas Lights Around The Globe

December 17, 2011 by Mike Nathan 7 Comments

They say that the holidays are a time to gather with others, which usually translates into spending time with friends and family. The folks at ioBridge Labs thought that while friends and family certainly are a big part of the holidays, it would be pretty cool to gather together flocks of strangers by using the Internet to synchronize their Christmas lights.

Participation in CheerLights is pretty easy, requiring little more than an Internet connection, some GE G-35 Color Effects lights, an Arduino, and an ioBridge. While those are the recommended components, an Arduino Ethernet shield will handle networking just as well. There really are no restrictions when it comes to hardware, so if you are so inclined, it should be relatively easy to roll your own display using simple RGB LEDs and a µC of your choosing.

The colors are dictated by the group’s Twitter feed, which can be found at http://twitter.com/#!/@cheerlights. Whenever a message is sent to @cheerlights along with a color, all of the light displays listening in will change simultaneously.

We really like the idea, and think it would be pretty cool to see this sort of program rolled out on a neighborhood or street-wide level, so you could see dozens of strings changing colors all at once.

If you’re interested in checking out CheerLights’ current color, be sure to take a gander at their live stream here.

[via BuildLounge]

Data Logging With A Cheap Lux Meter

December 16, 2011 by Mike Szczys 6 Comments

[Minisystem] has a thing for dynamo powered bike lights. He wanted to measure how well his latest is working, but just logging the current flow through the LEDs wasn’t enough for him. He picked up a cheap Lux meter and hacked into the circuit to log measurements while he rides.

He started by cracking open the case to see what the meter held inside. There’s a Texas Instruments Op-Amp that connects to the light sensor. The datasheet for the part didn’t help much, but [Minisystem] did find that the current output on one of the pins changes with light intensity. Further testing led him to discover that the signal is a multiple of 10 for what is shown on the Lux meter’s readout. All he needs to do is take regular measurement of this current and save that data.

To do this, he grabbed his trusty Arduino and made a connection between one of its analog inputs and the op-amp pin. It should be easy enough to dump measurements into the Arduino’s own EEPROM, or use an external storage chip or SD card.

[Thanks Jason]

Censoring All The ‘F’ Words On TV

December 15, 2011 by Brian Benchoff 25 Comments

[Milton] sent in a build that censors every ‘F’ word on TV, and not just the one that rhymes with ‘duck,’ either. His setup sounds the alarm every time someone inside the moving picture box says a word that contains the letter F.

The build is based around Nootropic Design’s Video Experimenter Shield. This neat little shield has been used as a video sampler and has analyzed what the talking heads are actually saying. The Video Experimenter Shield has support for closed captions, meaning a transcript from a TV show can be read in real-time. All [Milton] had to do so the ‘F word’ alarm could be sounded was strchr().

The F-Chip, as [Milton] calls his build, includes three outputs – a solenoid sounds a bicycle horn, sends some air through a whistle, and lights up an ‘F-word’ alarm. From the video of the F-Chip in action (available after the break), we can tell that this build is awesome, thoughtful, and annoying. The only way it could be made more annoying is by making an ‘E-word’ alarm, but there are ways around that.

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