Quick And Dirty Touch-sensitive Keyboard Project

June 3, 2013 by Mike Szczys 8 Comments

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

June 3, 2013 by Brian Benchoff 46 Comments

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.

Hardware Store Robot Hand

June 3, 2013 by Mike Szczys 12 Comments

hardware-store-robot-hand

Here’s a robot hand which can be built using mostly hardware store items. It doesn’t have the strongest of grips, but it does have lifelike movement. The demonstration video shows it picking up small objects like a metal nut.

The image above shows the ring and pinky fingers of the hand beginning to flex. These are controlled by the servo motors mounted in the palm area. The skeletal structure of each digit begins with the links of a bicycle chain. The links are first separated by removing the friction fit rods. Each rod is replaced with a screw and a nut, which also allows the springs (which open the digits) to be anchored at each ‘knuckle’.

[Aaron Thomen] didn’t stop the design process once the hand was finished. He went on to build a controller which lets you pull some rings with your fingers to affect movement. This movement is measured by a set of potentiometers and translated into electrical signals to position the hand’s servo motors. The demo, as well as two how-to videos are embedded below.

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Arduino-compatible, Quad-core ARM Dev Board

June 1, 2013 by Brian Benchoff 36 Comments

The Advent of the Raspberry Pi has seen an explosion in the market for ARM dev boards, sometimes even with pinouts for Arduino shields. The UDOO, though, takes those boards and ramps up the processing power for some very, very interesting builds.

The UDOO comes equipped with a dual or quad-core ARM CPU running at 1GHz with 1 GB of RAM. Also on board is the Atmel SAM3X8E – the same chip in the new Arduino DUE – and has pinouts for all those Arduino shields you have lying around.

In addition to serving your next project as a souped-up Raspberry Pi, UDOO also includes 78 (!) GPIO pins, Gigabit Ethernet, a camera connector, one SATA port (on the quad-core version), and an LVDS header for attaching LCD monitors. Basically, the UDOO is the motherboard of an ARM-powered laptop with the pinouts to handle Arduino shields. It’s just like [Bunnie]’s laptop, only this time you can actually buy it.

The UDOO doesn’t come cheap, though: on the UDOO Kickstarter, the dual-core version is going for $150 while the quad-core is priced at $170. Still, if you need the power to run a pair of Kinects or want to build an awesome torrent box, you’d be hard pressed to find a more powerful board.

High Speed Photography With Friggin’ Lasers

May 31, 2013 by Mike Szczys 14 Comments

[Bruce] built his own high-speed photography equipment for a fraction of the price it would have cost him to purchase it. He was inspired by a friend who showed him some example images. He headed into his shop and built an Arduino-based high-speed flash controller.

To capture an image like this one the camera is placed in a dark room and set for a long exposure. At just the right instant the flash is activating, capturing the image. In this case [Bruce] used an infrared laser diode pointed at a phototransistor to trigger the flash. When the droplet breaks the laser beam the Arduino triggers the flash after a calculated delay. It’s not specifically covered in his guide, but [Bruce] also mentions that this can be modified to use sound as a trigger. Here’s another sound-activated flash controller if you need inspiration.

The image at the top was made by dropping dye from a pipette into a pool of water. If you don’t have a pipette on hand you can head over to our LIFE blog to make one out of heat shrink tubing.

Ambilight Clone Has Meaningful Amount Of Resolution

May 29, 2013 by Mike Szczys 37 Comments

We don’t have an Ambilight clone on our own home theater, but seeing this one in action makes us wonder if we shouldn’t add it to the ever-growing list of projects we need to tackle (right below that POV display we’ve been putting off for years). [Falldeaf] built the colored light augmentation system using a set of WS2801 controlled LED pixels. There are a lot of them, and this results in the ‘meaningful resolution’ we mentioned in the title. The image on the screen is the opening to a James Bond film. You’ll remember that the camera shot down a rifle barrel follows him as he walks across the screen. There’s enough LEDs here to have to the light follow him across the screen as well. This is a nice touch that we don’t see in every Ambilight clone project.

A frame of fake-wood angle bracket holds each LED pixel in place. The entire assembly attaches to the VESA mounting holes on the back of the television. An Arduino addresses the lights while the Boblight package processes the video to acquire the lighting instructions. We think the hue is a bit off, but otherwise it’s a solid offering.

We’re still hoping the Microsoft IllumiRoom becomes a thing.

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Herd Single Cell Organisms With Your Mind

May 23, 2013 by Mike Szczys 7 Comments

mind-controlled-paramecium

Most project tips involving brainwaves get passed over because it’s hard to make much out of that type of control. This project doesn’t necessarily make progress on the control side on this, but you have to admit that herding life forms with your thoughts deserves a closer look.

[Geva] set up a rig that allows him to interact with paramecium — tiny single cell organism that are happy to swim around all day long. Just like vertebrates they’re not big fans of electric shocks. Run some current through the fluid and they’ll swim toward the negative electrode.

This experiment uses four pencil leads as electrodes. These are driven by an Arduino which reacts to the input from a toy brain wave device. Concentrate in just the right way and they will swim wherever you will them to.

This isn’t quite as involved as cockroach mind control, but it’s every bit as interesting
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