Quick And Dirty Touch-sensitive Keyboard Project

quick-dirty-touch-sensitive-keyboard

You don’t have to have high-quality parts to play around with electronics and here’s a great example. [Vishal] used junk to play around with CapSense, the touch sensitive Arduino library. What he ended up with is this touch-based piano keyboard.

We’ve featured the CapSense library in the past, but even that example uses a very meticulously crafted test rig of foil tape, protoboard, and some resistors. If you still haven’t given it a try follow this example of using aluminum foil, electrical tape, and a cardboard box.

[Vishal] just sandwiched the end of jumper wire between two pieces of foil to make each ‘key’. We believe the other end of the wire is soldered to the bias resistors where they connect to a couple of pin headers. The headers were hot-glued in place through holes in the bottom of the box, making the entire rig simple to plug into the Arduino board driving it. After adding in a small speaker and flashing the code he’s finished. It certainly makes for a short afternoon project which you won’t feel bad about taking apart later since you didn’t sink a ton of time or resources into the build.

Benchmarking USB Transfer Speeds

boards

[Paul Stoffregen], creator of the Teensy series of microcontroller dev boards, noticed a lot of project driving huge LED arrays recently and decided to look into how fast microcontroller dev boards can receive data from a computer. More bits per second means more glowey LEDs, of course, so his benchmarking efforts are sure to be a hit with anyone planning some large-scale microcontroller projects.

The microcontrollers [Paul] tested included the Teensy 2.0, Teensy 3.0, the Leonardo and Due Arduinos, and the Fubarino Mini and Leaflabs Maple. These were tested in Linux ( Ubuntu 12.04 live CD ), OSX Lion, and Windows 7, all running on a 2012 MacBook Pro. When not considering the Teensy 2.0 and 3.0, the results of the tests were what you would expect: faster devices were able to receive more bytes per second.  When the Teensys were thrown into the mix, though, the results changed drastically. The Teensy 2.0, with the same microcontroller as the Arduino Leonardo, was able to outperform every board except for the Teensy 3.0.

[Paul] also took the effort to benchmark the different operating systems he used. Bottom line, if you’re transferring a lot of bytes at once, it really doesn’t matter which OS you’re using. For transferring small amounts of data, you may want to go with OS X. Windows is terrible for transferring single bytes; at one byte per transfer, Windows only manages 4kBps. With the same task, Linux and OS X manage about 53 and 860 (!) kBps, respectively.

So there you go. If you’re building a huge LED array, use a Teensy 3.0 with a MacBook. Of course [Paul] made all the code for his benchmarks open source, so feel free to replicate this experiment.

Arduino Particle Light Box Generates Animations From Sound

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Simple tools used well can produce fantastic results. The hardware which [Gilad] uses in this project is the definition of common. We’d bet you have most if not all of them on hand right now. But the end product is a light box which seems to dance and twirl with every sound in the room. You should go watch the demo video before reading the bill of materials so that the simplicity doesn’t spoil it for you.

A wooden craft box serves as the enclosure. Inside you’ll find an Arduino board, microphone, and an 8×8 RGB module. The front cover of the project box diffuses the light using a sheet of tracing paper on a frame of foam board. It’s the code that brings everything together. He wrote his own particle system library to generate interesting animations.

If you don’t have a project box on hand this might work with an extra-deep picture frame.
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Moostar — Fortune Telling Moose Knock-off Of Zoltar

zoltare-the-fortune-telling-moose

Meet Moostar, the fortune-telling Moose inspired by Zoltar. You remember Zoltar, the coin operated fortune-teller who made [Tom Hanks] a rich movie star? Maybe you didn’t see that flick, but [Sketchsk3tch] did and he pulled this show piece together for a company-wide conference with relative ease.

If you’re good at choosing parts for your projects it makes things a lot simpler. He started with a singing Christmas moose, a mini plasma ball to act as the crystal ball, and somehow came across a collector’s basketball case which was the perfect size for the enclosure.

The electronics also came together remarkably well. He uses a thermal printer to spit out the fortunes — which are actually security tips for employees since that’s the dcpartment he works in. The coin acceptor is a Sparkfun part and he tried two ready made solutions to make the moose talk. The first is seen below and uses pre-recorded messages played by an Arduino Wave shield. This was improved upon by using an EMIC2 text-to-speech module that really opens up the moose’s range of chatter.

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Tracking Cicadas With Radiolab And An Arduino

Cicadia

Once every 17 years, a population of cicadas ranging from Connecticut to the Appalachian highlands of North Carolina emerges to annoy everyone within earshot. The last time east coasters saw this brood was in 1996, making 2013 yet another year of annoying insect pests. The only question is, when will we start to see this year’s cicada brood?

Radiolab, the awesome podcast and public radio show, has put together an awesome project that asks listeners to track when the cicadas in their area will emerge. Cicadas generally enter their loud and obnoxious adult stage when the ground temperature 8 inches below the surface reaches 64º F. Armed with an Arduino, thermistor, and a few wires and resistors, any Radiolab listener can upload soil temperature data to Radiolab servers where all the data will be correlated with documented cicada sightings.

After following the page’s instructions for wiring up a bunch of LEDs and a thermistor to an Arduino, just upload the most well-commented code we’ve ever seen and go outside to take soil temperature measurements. The temperature is displayed in a pseudo-binary format on nine LEDs. To decode the temperature without counting by powers of two, Radiolab has an online decoder that also allows you to upload your data and location.

Scooterputer, The All-in-one Scooter Computer

ScootDisplay-2

We’ve seen a fair share of carputer builds involving a Raspberry Pi in the last few months, but even the power of a Raspi can’t compete with the awesomeness of this Arduino-powered scooterputer.

Like all awesome projects, this build is the product of a massive case of feature creep. Initially, [Kurt] only wanted a voltage monitor for his battery. With an  Arduino Duemilanove, a voltage divider, and an evening of coding, [Kurt] whipped up a simple device with three LEDs to indicate the status of the batter: either low, good, or charging.

The project was complete until he ran across an awesome OLED screen. Using a touch screen display for just battery monitoring is a bit overkill, so [Kurt] made a trip over to Sparkfun and got his hands on a temperature sensor, real-time clock, accelerometer, GPS sensor, and even a cellular shield.

The resulting scooterputer is a masterpiece of in-vehicle displays: there’s a digital speedometer and GPS unit, and the cellular shield works as a tracking device and a way to download real-time maps of the scooter’s current location with itouchmap.

While the majority of the electronics are hidden under the hood of the scooter, the display of course needed to be out in the weather. To do this, [Kurt] found a nice enclosure with a rubber boot that perfectly fit the OLED display. The display is connected to the Arduino with a cat5 cable, and everything should hold up pretty well as long as [Kurt] doesn’t drive through a hurricane.

You can check out a video of the scooterputuer below.

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Automated Cat Feeder And Large Plastic Screws

We’ve seen automated food dispensers for pets, but none that go so far as to build large plastic screws for dispensing kibble.

This isn’t [Mathieu]’s first automatic cat feeder; an earlier version used a wheel to dispense cat food in excessively large version. To improve upon his first build, [Mathiu] decided to use an Archimedean screw to dispense food in 5 gram increments. There was a problem, though: a proper industrial screw cost about $1500 and the ‘consumer’ versions of what he wanted were trash. He though about casting one in epoxy but didn’t want to poison his cat with strange chemicals. He ended up using PolyMorph for his screw, a plastic that melts at 60º C and is also used in medical devices.

The electronics of the build are an Arduino, a  DS1307 real-time clock, LCD display, and a relay board powering an electric screwdriver motor. From the video demo below, we’re going to say [Mathieu] put together a pretty nice automated cat feeder.

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