Micro servomotors are a hacker staple. You’ll find maybe four or five in an RC plane, while a hexbot build could soak up a dozen or more of the cheap and readily available devices. Unfortunately, long-throw linear actuators are a little harder to come by, so it’s nice to know you can 3D-print linear gearing for standard micro RC servos and roll your own.
Currently on revision 2, [Roger Rabbit]’s design is not just a quick and dirty solution. He’s really thought through the problems he observed with his first revision, and the result is a robust, powerful linear actuator. The pinion fits a trimmed servo crank arm, the mating rack is stout and stiff, and early backlash problems have been solved. The whole case is easy to assemble, and as the video below shows, the completed actuator can lift 300 grams.
We like [Roger]’s build process, especially the iterative approach to improving the design. We’ll stay tuned to see where it goes next – a continuous rotation servo for extra-long throws? While we wait, you might want to check out [Richard Baguley]’s recent primer on servos if you want a little background on the underlying mechanism.
Continue reading “3D-Printed Case Turns Servo into Quality Linear Actuator”
It’s a dream come true: remote control of a real car. Besides being a lot of fun, a life-size RC vehicle has some practical applications, like performing rescue operations or delivering supplies to dangerous areas. For [Carter], [Dave], [Ryan], and [Sean], the dream became reality in the span of 24 caffeine-and-chicken-finger-fueled hours during an Ohio State University hackathon. They dubbed the system MagiKarpet because it sits in place of the floor mat and runs on pixies.
The plan was to control the throttle, brake, and steering of a Chevy Cobalt using a PlayStation controller. For added fun, a camera mounted high above the back bumper would provide a third-person view, and this feed would be displayed on a monitor in the backseat. Everything is controlled by an Arduino Mega. A beefy linear actuator works the brake and is attached temporarily with a band of Shapelock that slips around the pedal. The throttle is pushed by a lever attached to a car window motor. Another motor connects to the steering wheel with cables that can turn it 90° left and right. Although the build was successful, they ran into a couple of issues. But what’s a hackathon experience without a few problems?
The linear actuator was jammed for about an hour after some early testing, but they got it unstuck. The PS controller was borked, so they had to roll their own joysticks. The school wouldn’t let them actually drive it around because of safety (killjoys but we get it), so they put it up on a jack to demonstrate it for the judges. They took second place, though we can’t imagine what would have beat this. Check out the complete build video after the break.
You might remember these guys from last year around this time. They took first place at the same hackathon with Robottermilk Puncakes, a app-controlled pancake machine. Now that you’re hungry for pancakes, feast your eyes on this endless one.
Continue reading “Third Person Driving IRL”
RC servos are handy when you need to rotate something. You can even modify them to rotate continuously if that’s what you need. However, [Roger Rabbit] needed linear motion, but wanted the simple control afforded by an RC servo. The solution? A 3D printed housing that converts a servo’s rotation into linear motion.
The actuator uses five different parts, a few screws, and a common RC servo. The video shows the actuator pushing and pulling a 200g load with a 6V supply. There’s some room for adjustment, so different servos should work.
Continue reading “3D Printed RC Servo to Linear Actuator Conversion”
Industrial robot arms are curious devices, found everywhere from the back of old engineering classrooms where they taught kinematics in the 90s, to the factory floor where they do the same thing over and over again while contemplating their existence. For his Hackaday Prize entry, [Dan] is building a big robot arm. It’s not big enough to ride on, but it is large enough to automate a few processes in a reasonably well-equipped lab.
This is not a tiny robotic arm powered by 9 gram hobby servos. For the bicep and tricep of [Dan]’s arm, he’s using linear actuators – they’re high precision and powerful. A few months ago, [Dan] tried to design a hypocycloid gear but couldn’t get a $3000 prototype to work. Although the hypocycloid is out, he did manage to build a strange differential pan/roll mechanism for the wrist of the arm. It really is a thing of beauty, and with the engineering [Dan] has put into it, it’s a very useful tool.
If you’d like to meet [Dan]’s robot arm in person, he’ll be at the 2015 NYC Maker Faire this weekend. Check out [Dan]’s Hackaday Prize video for his robot arm below.
Continue reading “Hackaday Prize Semifinalist: An Affordable Robotic Arm”
When [JZSlenker] was challenged to find a creative way to destroy a bunch of compact discs that were burned incorrectly, he did not disappoint. He came up with a rather simple but fun contraption that launches the CD’s at high speeds and with a fast rate of fire. He doesn’t share many details about how this machine was built, but the 18 second video makes it pretty obvious how it works.
The CD gun is built mainly from a piece of plywood. This provides a flat base with which to mount the other components. A stack of compact discs is held in place by what appears to be a metal cage that was welded together. An inexpensive angle grinder is used as the propulsion mechanism. The grinding wheel is mounted just in front of the stack of CD’s in a vertical orientation. The wheel must be placed just high enough above the plywood base for a CD to fit in between the wheel and the base. This design is remarkably similar to the Sticker Gun which our own [Brian Benchoff] is building.
Some type of linear actuator is used as the firing mechanism. The actuator is hooked up to a thin piece of metal, cut into an L shape. It almost looks like a reaper tool. When a button is pressed, the actuator fires instantly. This pushes the metal hammer into the CD on the bottom of the stack. The CD is pressed forward into the grinder wheel which then shoots the CD into the air. Based on the below video, it looks like [JZSlenker] is able to fire at a rate of about three CD’s per second with this rig.
This has got to be a super-villain weapon for an upcoming movie, right? Maybe AOL-man?
Continue reading “Fully-Automatic CD Launcher Looks Dangerously Fun”
We have a pretty good guess where [Krizbleen] hides away any seasonal presents for his family: behind his shiny new secret library door. An experienced woodworker, [Krizbleen] was in the process of finishing the attic in his home when he decided to take advantage of the chimney’s otherwise annoying placement in front of his soon-to-be office. He built a false wall in front of the central chimney obstacle and placed a TV in the middle of the wall (directly in front of the chimney) flanked on either side by a bookcase.
If you touch the secret book or knock out the secret sequence, however, the right-side bookcase slides gently out of the way to reveal [Krizbleen’s] home office. Behind the scenes, a heavy duty linear actuator pushes or pulls the door as necessary, onto which [Krizbleen] expertly mounted the bookcase with some 2″ caster wheels. The actuator expects +24V or -24V to send it moving in one of its two directions, so the Arduino Uno needed a couple of relays to handle the voltage difference.
The effort spent here was immense, but the result is seamless. After borrowing a knock-detection script and hooking up a secondary access button concealed in a book, [Krizbleen] had the secret door he’d always wanted: albeit maybe a bit slow to open and close. You can see a video of its operation below.
Continue reading “Secret Attic Library Door”
[Roland] has already built a few very cool and extremely realistic flight sims, but his latest project will put his current rig to shame. He’s building a six degree of freedom simulator based on homebuilt linear actuators of his own design.
The actuator is powered by a large DC motor moving timing belts along the length of the enclosure. These timing belts are connected to a shaft that’s coupled to the frame with a few bungee cords. The bungee cords are important; without them, the timing belts would be carrying all the load of the sim – not a good thing if these actuators are moving an entire cockpit around a living room.
Also on [Roland]’s list of awesome stuff he’s building for his flight sims is a vibration system based on the BFF Shaker. This board takes data in from sim software and turns it into vibrations produced by either unbalanced DC motors or one of those ‘bass kicker’ transducers.
It’s all very cool stuff, and with all the crazy upgrades [Roland] is doing to his sim rig, he’s doing much better than paying $300/hour to rent a Beechcraft Baron.
Continue reading “DIY Linear Actuators For A Flight Sim”