servo

464 Articles

Making Your Anime Papercraft Move To The Music

September 25, 2012 by 15 Comments

This anime character is dancing to the music thanks to some animatronic tricks which [Scott Harden] put together. She dances perfectly, exhibiting different arm and head movements at just the right time. The secret to the synchronization is actually in the right channel of the audio being played.

The character in question is from an Internet meme called the Leekspin song. [Scott] reproduced it on some foam board, adding a servo to one arm to do the leek spinning, and another to move the head. These are both driven by an ATtiny44. All of the movements have been preprogrammed to go along with the audio track. But he needed a way to synchronize the beginning of each action set. The solution was to re-encode the audio with one track devoted to a set of sine wave pulses. The right audio channel feeds to the AVR chip via an LM741 opamp. Each sine wave triggers the AVR to execute the next dance move in the sequence. You can see the demo video for the project after the break.

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An Adafruit Raspberry Pi Extravaganza

August 18, 2012 by 4 Comments

The folks at Adafruit are busy as a bee working on bringing some of their really cool boards to the Raspberry Pi platform. Here’s a few that came in over the last few days:

16 servos is almost too many

Servos require a PWM output but the Raspi only has hardware support for PWM on a single GPIO pin; certainly not enough to build a gigantic, city-leveling robot. [Kevin] over at Adafruit put together a tutorial for using this 16 channel servo driver with the Raspi.

12 bit DAC

With only one PWM pin and no analog out, it was only a matter of time before someone hooked up the Adafruit 12 bit DAC to the Raspberry Pi.

16×2 LCD displays

Both the servo and DAC builds use the Adafruit I2C library and a bit of Python. Of course it’s possible to treat the GPIO pins on the Raspberry Pi as digital outs, just as [Mikey] did with his Raspi LCD display tutorial.

So, what distro are you using?

Of course all these builds use Adafruit’s Occidentalis distro, a maker-friendly Linux distro we’ve posted about before. It’s too useful to languish as a single Hackaday post, so here it is again.

Robot Servo Control Using Smartphone Audio Jack

August 14, 2012 by 10 Comments

[Jim] has an old Android phone he’d like to use as a Robot brain. It’s got a lot of the things you’d want in a robot platform; WiFi, Bluetooth, a camera, an accelerometer, etc. But he needed some way to make the mobile, mobile. What he came up with is a chassis with servos that can be controlled by the phone’s audio port.

To start his adventure he crafted a square wave audio file in Audacity and then played it back on the Android music player. By monitoring the output on an oscilloscope he found the wave was well produced, with peaks of about 1V. With that in mind he designed a circuit using two transistors to amplify the signal, thereby creating a usable input for the servo motors. Each motor has one of these circuits connected to it, with the left and right channels from the audio jack driving them separately. In the clip after the break you can see he even wrote a simple Android app to extend the idea to a more usable level.

This is a similar technique as used by the recon robot we saw about a year ago.

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Servos, Servos, And More Servos

July 21, 2012 by 22 Comments

For one reason or another, a lot of Hackaday readers are doing stuff with servos as of late. Here’s a few servo hacks that made their way into our tip line over the past day or so:

USB servo controller and a Stewart Platform

[Patricio] needed a way to control a bunch of servos for his thesis project. He came up with a USB servo controller (Spanish, here’s the translation) powered by a 40-pin PIC 18F microcontroller. The board connects to the USB port of a computer and supports up to 8 servos with 8 additional digital I/Os. Why all this horsepower? It’s for a Stewart Platform [Patricio] and his partner [Natalia] built.

Continuous rotation servos

Standard servos are usually limited to a rotation angle of somewhere between 140 and 160 degrees. Sometimes you need a continuous rotation servo, and those are a little more expensive. Every servo is a continuous rotation servo if you disable a the variable resistor as [Valentin] shows us. It’s a simple, if old, hack. It’s new to someone, though.

Eight servos on a Raspi

[Mikael] made a little board to attach to the GPIO header of his Raspberry Pi and control up to 8 servos. The board is running a serial interface with a small microcontroller on board. There’s nothing in the way of schematics or code, a testament for why you should always use a good email address when sending something into the HaD tip line. It seems [Mikael] is making a proper board, and we’ll more than happily give it a full post when it’s complete.

Laser Light Painting Includes Camera Control

July 13, 2012 by 6 Comments

This laser light painting setup can even control the camera. But it probably will not work with your average point-and-shoot. The exposure time used is somewhere around 2 seconds long, a feature which is hard to find on anything but DSLR cameras.

The setup relies on a red laser diode to do the painting. When viewed in real time you only see a dot tracing out a cryptic pattern and occasionally switching on and off. But with a long exposure the intense light persists to achieve an image like the one seen above. Note the ghosting around the rig as it has moved while the shutter was open.

The Arduino controlled device consists of a base which pivots the diode horizontally, with a servo for aiming on the vertical axis. Since the sketch is divided up by letter, we wonder how hard it would be to adapt this for use with a point-and-shoot? Perhaps you could capture one letter at a time and layer the frames in post production?

It seems this is a lot easier to build than some of the LED plotters we’ve looked at. If you do make your own don’t forget to send a link our way.

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Digital Picture Frame That Rotates To Match Image Orientation

July 12, 2012 by 7 Comments

This digital picture frame physically rotates in order to match the image’s orientation. [Markus Gritsch] built the frame, including a Python script to translate the photos to a format which makes the best use of the 2.4″ LCD screen.

The screen is addressed in 8-bit parallel by a PIC 32MX120F032B processor. Image are read from an SD card in a raw format, with 16-bit colors pushed to the display for each pixel. To get them into this format [Markus’] script converts the JPEG files to RAW, resizes them, uses dithering to reduce to 16-bit color, then applies a sharpening filter to improve the final look. During this process it also includes orientation information. That is parsed by the microcontroller and used to drive the servo motor to which the screen is attached.

To finish off the project he spray painted a piece of acrylic to act as a bezel for the frame. Check out the demo after the break and we think you’ll agree the rotating feature, along with image scrolling, really makes this a piece you’ll want on your own desk.

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Adding A Bomb Bay To A Quadcopter

July 2, 2012 by 24 Comments

The Fourth of July is fast approaching, and what better way to celebrate the independence of your country than by blowing up a small piece of it? [Anzel360] decided to take that line of thought to a whole new level by adding a bomb bay to his quadrocopter.

[Anzel360] recently upgraded his transmitter to a Spektrum DX8, giving him two extra channels on his four-channel quadrotor. After adding a small servo to the quad, it was a simple matter of taping a box to the undercarriage and filling it full of fireworks.

The ammo [Anzel] is using is just a handful of Snappin’ Pops – otherwise known as the lamest firework ever created. We won’t hold that against him, though; a remote ignition system for a few Black Cats mounted on a fancy quadrocopter is just asking for trouble. We do recall a throwable cap gun bomb from our youth, though, that would allow for year-round ammo replenishment…