[Keith Baxter] has undertaken something of a ‘Mount Everest’ of guitar modifications. He’s developing a Servoelectric guitar that trades frets for a keypad. It is still a guitar in the sense that it has a body, strings, and pickups to sense the strings vibrations and pass them to an amplifier. The left hand, which traditionally would shorten the strings as needed by pressing them against a fret, now changes string pitch using a keypad. This is an interesting fusion between traditional guitar and 80’s phenomenon, the keytar.
Each string is connected to a different servo motor. When a key on the keypad is pressed, the corresponding servo adjusts the tension of that string, bringing it in tune at the new pitch. His original design involved a lot of custom circuitry but he’s evolved the project to include an Arduino controller. This second generation both simplifies the control circuitry and improves upon it.
We’ve embedded some video after the break. In the first example you can see the strings adjusting for each new pitch. In the second, take a look behind the guitarist… what do you think he’s got planned for those giant capacitors?
Starting a new robotics project and want to find the perfect servo for the job? It can be a real pain in butt sometimes. This is where ServoDatabase.com comes in. They’re compiling specifications and reviews on servos. We love seeing these databases pop up. Remember the online chip reference? You simply can not have too much reference material.
[Mikal] wanted to create an awesome electronic wedding gift for his friend who was moving to France. After experimenting with a few things, he settled on creating a puzzle box that would only open in a certain location. Since his friend introduced him to the Arduino, he fittingly used one in the design, along with a serial GPS module and a mini character LCD. The box itself is locked using a servo-controlled chopstick, which could theoretically be snapped if [Mikal] really screwed something up. To save battery life, he used a small Pololu module to provide power that uses only 0.01 microamps in standby, and can be shut off by the Arduino.
The box was designed to be mysterious yet self-explanatory. When the button on the front is pushed, the box comes to life for 3 minutes, displaying the distance away from secret location. Additionally, it warns how many tries are left: the button can only be pushed 50 times before it is sealed “forever”. In order to open the box, you have to be within 2km of the destination. Theoretically, you can narrow down the location to one of 2 points after 2 readings, but a less scientific approach would probably be a lot more fun.
This seems like an amazing gift, and the same concept could be repurposed into hundreds of other devices. For extra fun, he could have placed it at a geocache location.
[Amnon] is learning the hard way that water and electronics don’t always like to play nicely together. He’s been working on creating a swimming fish that uses three servos to flex a sheet of fish-shaped polycarbonate. This photo doesn’t really do the project justice but you can get a better idea of what he’s accomplished by watching the videos after the break.
The three servos along with some distance sensors for obstacle avoidance are all controlled by a PIC 16F877A microcontroller. [Amnon] tried out three different waterproofing methods; coating the device in varnish, dipping it in hot glue, and dipping it in epoxy. The first two resulted in water damage to the electronics, but the third managed to work. It kept the water out, but also prevents reprogramming of the controller.
Although not successful, we would have loved to see the process of dipping the fish in a churning vat of molten glue. Once perfected, this may be the perfect platform for carrying our weapons of doom.
Halloween is a scary time for the little ones. It’s dark, they can barely see through their injection molded Spiderman masks, but it’s all worth it for the candy.
Our friends over at Evil Mad Scientist Labs have produced a pumpkin that moves on its own. The little pumpkin was disemboweled from the bottom and its guts were replaced by a simple robot. Three Lego wheels provide this base with one attached to a continuous rotation servo that provides the motion. The device is powered by 3 AAA batteries and powered by an Atmel ATtiny2313 microcontroller. For added terror there are two green LEDs that act as ghoulish eyes.
We’ve embedded the video of the Rovin Pumpkin in action after the break. This is a wonderfully simple way to spice up your front porch decorations on All Hallows’ Eve. Read the rest of this entry »
There are people who buy a cheap sack of candy and dutifully answer the door on Halloween. Then there are people like [Peter] who spend the whole year planning for the next year’s Hollywood-style front yard theatrics.
He added an animatronic raven to his show a few years back. It has been wildly popular and it’s not hard to see why. The bird is well engineered, well built, and the performance is very realistic. [Peter], who is an FX supervisor in the film industry, has posted a build log that takes us through step by step. This creepy performer can move its head up and down, side-to-side, and even rotate at the neck. This all happens while the beak synchronizes with talking. We marvel at the precision machining that was done to make the frame facilitate movement.
The body itself is made of fiberglass covered with feathers. [Peter] covered the completed mechanics with clay in order to sculpt the final body shape. This was used as the mold by covering it with fiberglass release and then fiberglass fabric. This process produced a very light weight and accurate shell with a minimum of effort; something we’ll keep in mind for future projects.
Take a look at a bit of video after the break. You can see the whole show from past years over at [Peter's] site. We’ll be doing a couple of follow-ups covering his animatronic skeleton (the raven’s partner in crime) as well as the interface he uses to control and sync the voices to stay tuned! Read the rest of this entry »
[Spikenzie] has put together this nice kit for controlling a DC motor with RC servo signals. He’s using a PIC12F629 to convert the signal to PWM. As you can see in the video above, it seems to work quite well. It is in a neat and tidy package and available as a kit. We have to admit though, what caught our eye was the prototype. Even though it is a kit for sale, it looks as though they plan on releasing the PCB files and code.
Robot enthusiast [Vitalijus Rodnovas] built this rig to allow a humanoid robot to mimic his own body movements in real time. [Rodonovas] refers to his man-machine interface as a “master-slave suit,” but elsewhere this is often called a waldo after a prescient 1942 [Robert Heinlein] novella. This project page is slight on details and is mostly written in his native Lithuanian, but the pictures speak volumes, and with a little help from Google Translate we can learn the essential facts: The robot itself is a commercially-available kit, the Kondo KHR-1HV from Japan. The custom-built harness uses a collection of surplus Soviet-era military potentiometers (acquired on eBay) to read the positions of his elbows and shoulders, then an ATmega8-based interface board translates these readings into motion commands sent to the robot’s onboard controller. Some additional notes and code can be found on the RoboSavvy Forum.
Does it work? Just watch. His grin as the video progresses is infectious!
Introducing ERP: Experimental Robotic Platform. This is an open source, modular robotics platform that, as you can see above, didn’t fair too poorly in the Robogames 2009. [John] has been working on this platform for roughly 2 years and states that it will never be “finished”. It is a development platform, and is always changing and being updated. You can follow along on the project page to see the major design changes as they happen, such as the wheel suspension system cut from a single piece of plastic. All of the pieces, schematics, and software are available for download. Be sure to scroll down and see ERP’s reaction to some of crabfu’s inventions.
Here is a nice video to wind down the day. It’s [neorazz]’s micRo playing the theme from Tetris. The micRo is a simple CNC kit sold by the team at Lumenlabs. For more servo music, peruse our CNC category.
