Roboceratops: A Robot Dinosaur That Defies Extinction

roboceratopsInspired by a childhood love of dinosaurs, [Robert] set out to build a robotic dinosaur from the Ceratopsian family. After about a year of design, building, and coding, he has sent us a video of Roboceratops moving around gracefully, chomping a rope, and smoothly wagging his tail.

Roboceratops is made from laser-cut MDF and aluminium bars in the legs. That’s not cookie dough on those legs, it’s upholstery foam, and we love the way [Robert] has shaped it. Roboceratops has servos in his jaw, neck, tail, and legs for a total of 14-DOF. You can see the servo specifics and more in the video description. [Robert] has full kinematic control of him through a custom controller and is working to achieve total quadrupedal locomotion.

Inside that custom controller is an Arduino Mega 2560, an LCD, and two 3-axis analog joysticks that control translation, height, yaw, pitch, and jaw articulation. For now, Roboceratops receives power and serial control through a tether, but [Robert] plans to add an on-board µC for autonomous movement as well as wireless, a battery, an IMU, and perhaps some pressure/contact detection in his feet.

The cherry on top of this build is the matching, latching custom carry case that has drawers to hold the controller, power supply, cable, tools, and spare parts. Check out Roboceratops after the break.

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THP Hacker Bio: nsted

 

thp-contestant-bio-nsted

Have you ever wanted to build a robot arm, or even a full robot, but were put off by the daunting task of making all of those articulations work? Moti could make that a lot easier. The project seeks to produce smart servo motors which can connect and communicate in many different ways. It’s a great idea, so we wanted to know more about the hacker behind the project. After the jump you’ll find [nsted's] answers to our slate of question for this week’s Hacker Bio.

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ServoBender, The Electronic Pedal Steel

Servo

You’ve most certainly heard a pedal steel guitar before, most likely in any ‘old’ country song, or more specifically, any country song that doesn’t include the word ‘truck’ in its lyrics. Pedal steels are strange devices, looking somewhat like a 10-string guitar with levers that change the pitch of individual strings. Historically, there have been some attempts to put a detuning mechanism for individual strings in normal electric guitars, but these are somewhat rare and weird. [Gr4yhound] just nailed it. He’s come up with the perfect device to emulate a pedal steel in a real guitar, and it sounds really, really good.

The imgur album for this project goes over the construction of the ServoBender in a bit more detail than the video. Basically, four servos are mounted to a metal plate below the bridge. Each servo has a spring and cam system constructed out of 3D printed parts. The detuning is controlled by an Arduino and a few sustain pedals retrofitted with hall effect sensors. Simple, really, but the effect is astonishing.

[Gra4hound]‘s contraption is actually very similar to a B-Bender where a guitarist pushes on the neck to raise the pitch of the B string. This setup, though, is completely electronic, infinitely adjustable, and can be expanded to all six strings. Very, very cool, and it makes us wonder what could be done with one of those freaky robot guitars, a soldering iron, and a bit of code.

Video below, because you should watch it again.

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Attiny PWM Generator and Servo Tester

PWM-Servo-Tester

Having the right tool for the job makes all the difference, especially for the types of projects we feature here at Hackaday. [Jan_Henrik's] must agree with this sentiment, one of his latest projects involves building a tool to generate a PWM signal and test servos using an Attiny25/45/85.

Tools come in all kinds of different shapes and sizes. Even if it might not be as widely used as [Jan_Henrik's] earlier work that combines an oscilloscope and signal generator, having a tool that you can rely upon to test servos and generate a PWM can be very useful. This well written Instructable provides all the details you need to build your own, including the schematic and the necessary code (available on GitHub). The final PWM generator looks great. For simple projects, sometimes a protoboard is all you need. It would be very cool to see a custom PCB made for this project in the future.

What tools have you build recently? Indeed, there is a tool for every problem. Think outside the (tool) box and let us know what you have made!

The Un-Digital Robotic Arm

556When you think of a robotic arm, you’re probably thinking about digital control, microcontrollers, motor drivers, and possibly a feedback loop. Anyone who was lucky enough to have an Armatron knows this isn’t the case, but you’d still be surprised at how minimal a robotic arm can be.

[viswesh713] built a servo-powered robotic arm without a microcontroller, and with some interpretations, no digital control at all. Servos are controlled by PWM signals, with a 1 ms pulse rotating the shaft one way and a 2 ms pulse rotating the shaft the other way. What’s a cheap, popular chip that can easily be configured as a timer? Yep, the venerable 555.

The robotic arm is actually configured more like a Waldo with a master slave configuration. [viswesh] built a second arm with pots at the hinges, with the resistance of the pots controlling the signal output from a 556 dual timer chip. It’s extremely clever, at least until you realize this is how very early robotic actuators were controlled. Still, an impressive display of what can be done with a simple 555. Videos below.

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Servo Stock, The Future Of 3D Printers

printerIf you think about it, the RepRaps and other commercial 3D printers we have today are nothing like the printers that will be found in the workshops of the future. They’re more expensive than they need to be, and despite the RepRap project being around for a few years now, no one has cracked the nut of closed loop control yet. [mad hephaestus], [Alex], and [Will] over on the Hackaday Projects site are working on the future of 3D printing with the Servo Stock, a delta printer using servos and closed loop control to build a printer for about a quarter of the price as a traditional 3D printer.

The printer itself is a Kossel derivative that is highly modified to show off some interesting tech. Instead of steppers, the printer has three axes controlled by servos. On each axis is a small board containing a magnetic encoder, and a continuous rotation servo. With this setup, the guys are able to get 4096 steps per revolution with closed loop control that can drive the servo to with ±2 ticks.

The electronics and firmware are a clean sheet redesign of the usual 3D printer loadout. The motherboard uses a Pic32 running at 80MHz. Even the communication between the host and printer has been completely redesigned. Instead of Gcode, the team is using the Bowler protocol, a system of sending packets over serial, TCP/IP, or just about any other communications protocol you can think of.

Below is a video of the ServoStock interpreting Gcode on a computer and sending the codes and kinematics to the printer. It seems to work well, and using cheap servos and cut down electronics means this project might just be the first to break the $200 barrier for a ready to run 3D printer.

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Roboartist Draws What It Sees

roboartist-vector-image-machine

The perfect balance of simplicity and complexity have been struck with this automated artist. The Roboartist is a vector drawing robot project which [Niazangels], [Maxarjun], and [Ashwin] have been documenting for the last few days. The killer feature of the build is the ability to process what is seen through a webcam so that it may be sketched as ink on paper by the robotic arm.

The arm itself has four stages, and as you can see in the video below, remarkably little slop. The remaining slight wiggle is just enough to make the images seem as if they were not printed to perfection, and we like that effect!

Above is a still of Roboartist working on a portrait of [Heath Ledger] in his role as Joker from The Dark Knight. The image import feature was used for this. It runs a tweaked version of the Canny Edge Detector to determine where the pen strokes go. This is an alternative to capturing the subject through the webcam. For now MATLAB is part of the software chain, but future work seeks to upgrade to more Open Source tools. The hardware itself uses an Arduino Mega to take input via USB or Bluetooth and drives the quartet of servo motors accordingly.

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