Prototyping A Modular LED Matrix

March 18, 2013 by Mike Szczys 23 Comments

led-matrix-modular-prototype

[Will] was toying with the idea of creating a scrolling LED marquee to display messages as his wedding in May. But you’ve got to crawl before you can walk so he decided to see what he could do with the MAX7219 LED driver chips. They do come in a DIP package, but the 24-pin 0.1″ pitch chip will end up being larger than the 8×8 LED modules he wanted to use. So he opted to go with a surface mount part and spun a PCB which makes the LEDs modular.

These drivers are great when you’re dealing with a lot of LEDs (like the motorcycle helmet of many blinking colors). Since they use SPI for communications it’s possible to chain the chips with a minimum of connections. [Will] designed his board to have a male header on one side and a female socket on the other. Not only does it make aligning and connecting each block simple, but it allows you to change your mind at any time about which microcontroller to use to command them. For his first set of tests he plugged the male header into a breadboard and drove it with an Arduino. We hope to hear back from him with an update when gets the final device assembled in time for the big day.

No-touch Music Player

March 13, 2013 by Mike Szczys 10 Comments

no-touch-mp3-player

This little box not only plays tunes, but it lets you control several aspects of playback without touching a thing. [Thomas Clauser] calls it the LighTouch and we like it because it uses inaudible sound to control audible sound.

We think the pair of cylinders sticking up through the top of this project enclosure will be recognized by most readers as the business end of an ultrasonic rangefinder. This is the only control interface which [Thomas] chose to use. Although he didn’t write very extensively about the specific control scheme he implemented, the video embedded in his post shows some of the gestures that cause the Arduino inside to change its behavior. For instance, a swipe of the hand at higher level starts playback, swiping at a lower level pauses it. When adjusting the volume the box responds to how close his hand is to that sensor. With this control in place, the music side of these things is simply handled by a music shield he is using.

Mailbox Notifier Texts When The Letter Carrier Arrives

March 13, 2013 by Mike Szczys 71 Comments

mailbox-notifier

[Felix Rusu’s] mailbox is on the other side of the street and he’s got a pretty big front yard. This means checking for mail is not just a pop your head out of the door type of activity. This becomes especially noticeable during the winter months when he has to bundle up and trudge through the snow to see if his letter carrier has been there yet. But he’s made pointless trips a thing of the past by building a notifier that monitors the mailbox for him.

He’s using a Moteino, which is an Arduino clone of his own making. It’s tiny and features an RF module on the underside of the board which takes care of communicating with a base station inside the house. The module seen above rolls the microcontroller board up along with a 9V battery and a hall effect sensor which can tell if the mailbox door is open or closed. When the Arduino detects a change to that sensor it pushes some data back to the base station which then relays the info to a computer or Raspberry Pi in order to send him a text message. All of this is shown off in the video after the break.

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Laser Toting Robot Taunts House Cat

March 11, 2013 by Mike Szczys 26 Comments

laser-toting-robot-taunts-house-cat

[Rodney Lederer] and his cat were bored after moving to a new city. He fixed that for both of them by taking on this project which turns a Wowwee robot into feline entertainment.

It’s no secret that cats have a weakness for the little red dot produced by a laser pointer. [Rodney] put that trait to work by automating the movement of a red laser pointer. After mounting it on a servo motor he got down to work programming an Arduino to move it in a playful manner. But it wouldn’t have been much fun if the this was only capable of preprogrammed patterns, so he also included an IR proximity sensor to help give the thing interactivity. Add to that the treaded robot base and you’ve got mobile cat entertainment. The proof is in the video after the break… the cat is certainly having fun chasing the dot. [Rodney] plans to work a bit more on his code so that the motions of the laser dot include a lot of different patterns to keep things exciting.

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Dispensing Change For Low-stakes Gambling

March 9, 2013 by Brian Benchoff 3 Comments

change

Every year, [Nathan] hosts an Oscar party with a lot of drinking, adoring the off-color comments of [Joan Rivers] and some low stakes wagering. Everyone throws a dollar into the pot for a particular award, and when the winner is announced, [Nathan] splits the pot between the winners and begins counting out coins. As convenience stores have discovered, there’s an easier way to dole out pocket change, so this year [Nathan] created a change machine that dispenses coins for the winners.

The change machine is just like the ones you would find at a supermarket or convenience store; load up the machine with a few rolls of coins, and a few solenoids fire in response to serial data received from a computer. [Nathan] used an Arduino, Serial shield, button matrix, and LCD display for his change machine interface, allowing him to dispense pocket change to each of the winners after an award is announced.

Real Multifunction “Sonic Screwdriver”

March 7, 2013 by Ryan Fitzpatrick 30 Comments

dr who sonic screwdriver

“I don’t understand, you don’t have the technology.” OK, so it’s not actually a futuristic tool with the same capabilities as the one off the hit TV series Dr. Who, but this homemade “sonic screwdriver” is a multifunction device that’s pretty cool nonetheless.

Created around an Arduino Pro Mini, [Gunther] really one-upped the last screwdriver we featured. Built in functions include: brown note tone generator, dog whistle, EMF meter, flashlight, IR universal remote, laser pointer, ohm meter, sound level meter, voltage detector, and a voltage meter. You can also have an electromagnet or output voltage supply if you want. If that wasn’t enough, it can even play the theme song from Star Wars! Whew. That’s a mouthful of functionality.

Although he has posted the Arduino code, you’ll have to keep an eye on his site for more details if you want to create your own. He’s mentioned that he’s working on blue prints and a full parts list… Awesome. Now where’s that lock pick function?

Check out a video showing off some of the features after the break.

[via Make]
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Wireless Pinball Controller For Tablet Gaming

March 4, 2013 by Mike Szczys 6 Comments

wireless-pinball-controller

This wooden box is a wireless pinball controller and tablet stand. The idea is to set it on a workbench to give you some of the thrill of standing and playing the real thing. [Jeff] has been rather addicted to playing a pinball app on Android lately, and started the journey because he needed a way to give his thumbs some relief.

An Arduino monitors buttons on either side of this wooden controller. [Jeff] is new to working with hardware (he’s a Linux Kernel developer by trade) and was immediately struck with button debouncing issues. Rather than handle this in software (we’ve got a super-messy thread on that issue with our favorite at the bottom) he chose a hardware solution by building an SR latch out of two NAND gates.

With the inputs sorted out he added a BlueSMiRF board to the project which allowed him to connect a Nexus 7 tablet via Bluetooth. At this point he ran into some problems getting the device to respond to his control as if it were an external keyboard. His stop-gap solution was to switch to a Galaxy Tab 10.1 which wasn’t throwing cryptic errors. Hopefully he’ll fix this in the next iteration which will also include adding a plunger to launch the pinball, a part which just arrived in the mail as he was writing up this success.

We’ve embedded his quick demo video after the break.

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