Posts | Comments

Planet Arduino

Archive for the ‘servo’ Category

This servo/gear reduction was assembled with almost all 3D-printed parts. Apart from a brushed 36 V DC-motor, a stainless steel shaft, and screws for holding the servo together, the only other non-printed part is the BTS7960B motor driver.

Some interesting stats about the plastic servo – its stall torque is about 55 kg/cm, reaching a peak current draw of 18 A when using a 6s LiPo battery outputting 22-24 V. The shaft rotates using two 20 mm holes and lubrication. (Ball bearings were originally in the design, but they didn’t arrive on time for the assembly.)

The holes of the gears are 6.2 mm in diameter in order to fit around the shaft, although some care is taken to sand or fill the opening depending on the quality of the 3D print.

This isn’t [Brian Brocken]’s only attempt at 3D-printing gears. He’s also built several crawling robots, a turntable, and a wind up car made entirely from acrylic. The .stl files for the project are all available online for anyone looking to make their own 3D-printed servo gears.

LEDs and blinky projects are great, and will likely never fade from our favor. But would you look at this sweeping beauty? This mesmerizing display is made from 36 micro servos with partial Popsicle sticks pasted on the arms. After seeing a huge display with 450 servos at an art museum, [Doug Domke] was inspired to make a scaled-down version.

What [Doug] didn’t scale down is the delightful visuals that simple servo motion can produce. The code produces a three-minute looping show that gets progressively more awesome, and you can stare at that after the break. Behind the pegboard, a single, hardworking Arduino Uno controls three 16-channel PWM controllers that sweep the servos. We like to imagine things other than Popsicle sticks swirling around, like little paper pinwheels, or maybe optical illusion wheels for people with strong stomachs.

You won’t see these in the video, but there are five ultrasonic sensors mounted face-up on the back of the pegboard. [Doug] has optional code built in to allow the servo sticks to follow hand movement. We hope he’ll upload a demo of that feature soon.

Servos can be hypnotic as well as helpful, as we saw in this 114-servo word clock.

Via Arduino blog

There’s nothing quite like building something to your own personal specifications. It’s why desktop 3D printers are such a powerful tool, and why this scalable plotter from the [Lost Projects Office] is so appealing. You just print out the end pieces and then pair it with rods of your desired length. If you’ve got some unusually large computer-controlled scribbling in mind, this is the project for you.

The design, which the team calls the Deep Ink Diver (d.i.d) is inspired by another plotter that [JuanGg] created. While the fundamentals are the same, d.i.d admittedly looks quite a bit more polished. In fact, if your 3D printed parts look good enough, this could probably pass for a commercial product.

For the electronics, the plotter uses an Arduino Uno and a matching CNC Shield. Two NEMA 17 stepper motors are used for motion: one to spin the rod that advances the paper, and the other connected to a standard GT2 belt and pulley to move the pen back and forth.

We particularly like the way [Lost Projects Office] handled lifting the pen off the paper. In the original design a solenoid was used, which took a bit of extra circuitry to drive from the CNC Shield. But for the d.i.d, a standard SG90 servo is used to lift up the arm that the pen is attached to. A small piece of elastic puts tension on the assembly so it will drop back down when the servo releases.

If this plotter isn’t quite what you’re after, don’t worry. There’s more where that came from. We’ve seen a number of very interesting 3D printed plotters that are just begging for a spot in your OctoPrint queue.

In the movie Wall-E, future humans live in floating chairs and have everything done for them. Today, we grumble if we have to go to physically find a light switch or a remote control. How far away can floating chairs with screens be? T2, the Tea Bot, gets us one step closer to that. Using a laser-cut frame, an ESP8266, and a servo motor, the T2 brews your tea for exactly the right amount of time.

We were kind of hoping the robot would at least dunk the tea bag in and out, but it does provide a web interface that lets you select the brew. Of course, the code is available, so you could make modifications — maybe turn on a hotplate underneath the cup.

While this isn’t particularly practical for most people, it is a nice short example of how to provide a web interface and do something with an ESP8266. Maybe you want to lock a desk drawer or put a marshmallow into a flame, for those tasks you could use very similar code.

Since a servo takes a pulse width and draws very little current, you could probably drive a bunch of them and parallel process a lot of teacups if you were serving a crowd. Naturally, this isn’t the first automated brewer we’ve seen. It isn’t even the only one with a servo.

Anansi in African folktale is a trickster and god of stories, usually taking physical form of a spider. Anansi’s adventures through oral tradition have adapted to the situation of people telling those stories, everything ranging from unseasonable weather to living a life in slavery. How might Anansi adapt to the twenty-first century? [odd_jayy] imagined the form of a cyborg spider, and created Asi the robot companion to perch on his shoulder. Anyone who desire their own are invited to visit Asi’s project page.

Asi was inspired by [Alex Glow]’s Archimedes, who also has a project page for anyone to build their own. According to [Alex] at Superconference 2018, she knew of several who have done so, some with their own individual customization. [odd_jayy] loved the idea of a robot companion perched on his shoulder but decided to draw from a different pool of cultural folklore for Asi. Accompanying him to various events like Sparklecon 2019, Asi is always a crowd pleaser wherever they go.

Like every project ever undertaken, there is no shortage of ideas for Asi’s future and [odd_jayy] listed some of them in an interview with [Alex]. (Video after the break.) Adding sound localization components will let Asi face whoever’s speaking nearby. Mechanical articulation for legs would allow more dynamic behaviors while perched, but if the motors are powerful enough, Asi can walk on a surface when not perched. It’s always great to see open source projects inspire even more projects, and watch them as they all evolve in skill and capability. If they all become independently mobile, we’ll need clarification when discussing the average velocity of an unladen folklore robot companion: African or European folklore?

Regular readers of Hackaday have certainly seen the work of [Jeremy Cook] at this point. Whether you remember him from his time as a writer for this fine online publication, or recognize the name from one of his impressive builds over the last few years, he’s a bona fide celebrity around these parts. In fact, he’s so mobbed with fans at events that he’s been forced to employ a robotic companion to handle distributing his personalized buttons for his own safety.

Alright, that might be something of a stretch. But [Jeremy] figured it couldn’t hurt to have an interesting piece of hardware handing out his swag at the recent Palm Bay Mini Maker Faire. Anyone can just put some stickers and buttons in a bowl on a table, but that’s hardly the hacker way. In the video after the break, he walks viewers through the design and construction of this fun gadget, which takes a couple unexpected turns and has contains more than a few useful tips which are worth the cost of admission alone.

Outwardly the 3D printed design is simple enough, and reminds us of those track kits for Matchbox cars. As you might expect, getting the buttons to slide down a printed track was easy enough. Especially when [Jeremy] filed the inside smooth to really get them moving. But the goal was to have a single button get dispensed each time the device was triggered, but that ended up being easier said than done.

The first attempt used magnets actuated by two servos, one to drop the button and the other to hold up the ones queued above it. This worked fine…at first. But [Jeremy] eventually found that as he stacked more buttons up in the track, the magnets weren’t strong enough to hold them back and they started “leaking”. This is an excellent example of how a system can work perfectly during initial testing, but break down once it hits the real world.

In this case, the solution ended up being relatively simple. [Jeremy] kept the two servos controlled by an Arduino and a capacitive sensor, but replaced the magnets with physical levers. The principle is the same, but now the system is strong enough to hold back the combined weight of the buttons in the chute. It did require him to cut into the track after it had already been assembled, but we can’t blame him for not wanting to start over.

Just like the arcade inspired candy dispenser, coming up with a unique way of handing out objects to passerby is an excellent way to turn the ordinary into a memorable event. Maybe for the next iteration he can make it so getting a button requires you to pass a hacker trivia test. Really make them work for it.

Sometimes you have an idea, and despite it not being the “right” time of year you put a creepy skull whose eyes tell the time and whose jaw clacks on the hour into a nice wooden box for your wife as a Christmas present. At least, if you’re reddit user [flyingalbatross1], you do!

The eyes are rotated using 360 degree servos, which makes rotating the eyes based on the time pretty easy. The servos are connected to rods that are epoxied to the spheres used as eyes. Some water slide iris decals are put on the eyes offset from center in order to point in the direction of the minutes/hours. An arduino with a real time clock module keeps track of the time and powers the servos.

Check out the video after the break:

The jaw opens and closes on the hours – springs are screwed to the inside of the jaw to the outside of the skull behind the bones that surround the eyes; they’re hidden when the skull is in its box. A third servo is used as a winch to pull the jaw open from the inside of the bottom of the chin. When it releases, the springs close the mouth and the clack of the teeth replaces an hourly chime.

A bit late (or early) for Halloween, but it’s a really fun project. [Flyingalbatross1] has made the arduino code available, as well as showing plenty of images of how the parts are put together. Take a look at this this atomic clock-in-a-skull, or you make your own talking skull for Halloween!

via Reddit

The junk bin can be a great source of inspiration, unless you’re too familiar with the contents to be imaginative with them. But thrift stores are another matter, like giant junk bins that are constantly replenished by underappreciated elves. You never know what kinds of goodies they will pile on the shelves, so it’s easy to become a fixture and visit them once or thrice a week.

[Hunter Irving] haunts a few choice thrift stores in his neighborhood, and a few months ago he found a knockoff Thomas the Tank Engine with an articulated face. It uses a simple mechanism to produce an impressive amount of movement, especially for a cheap knockoff toy. Both of its eyes slide sideways and its mouth opens, resulting in a very animated (and terrifying) range of expressions. Sensing an opportunity to turn his animatronic robot dreams into karaoke-singing nightmare fuel for the rest of us, he forked over a few bucks and took it home.

As luck would have it, a 9g micro servo fit perfectly in the back of the frightening little face. [Hunter] designed an axle to transfer motion to the face mechanism, but it broke almost immediately. We applaud his Plan B, though, which consists of a mounting block for the servo, and a cable tie armature connected with screws. Once that was sorted, [Hunter] designed a bulbous body for it in Blender.

This terrifying train-faced toy uses an Arduino Leonardo to read MIDI note-on and -off messages, and opens his mouth when appropriate to sing hit favorites in a smooth, speech-synthesized contralto. Pour yourself a strong beverage and enjoy the build/demo video after the break.

Interested in making your own? [Hunter] has all the files up on his Patreon page. For just $1, you can access the code, synth files, and STL files. While you’re there, you can also get the scoop on his Nintendo LABO waveform cards.

 

These days, photochromic lenses are old-hat. Sure, it’s useful to have a pair of glasses that automatically tints due to UV light, but what if you want something a little more complex and flashy? Enter [Ashraf Minhaj]’s SunGlass-Bot.

The build is simple, beginning with an Arduino Pro Mini for reasons of size. Connected to the analog input is a light-dependent resistor for sensing the ambient light level. This reading is then used to decide whether or not to move the servo which controls the position of the lenses. In low light, the lenses are flipped up to allow clear vision; in brighter light, the lenses flip down to protect the eyes. Power is supplied by a homebrew powerbank that it appears [Ashraf] built from an old phone battery and a small boost converter board. All the files to recreate the project are available on Github, too.

It’s a fun build that [Ashraf] shows off in style. While this may not be as effortless as a set of Transition lenses or as quick as a welding mask filter, it has a certain mechanical charm that wouldn’t be out-of-place in a certain sci-fi aesthetic.

Hungry for more? Check out these self-blending sunglasses we featured a while back. Video after the break.

[NathanKing] has a cute, rambunctious pupper who eats way too fast for her own good. He’s tried various distribution methods intended to get her to slow down, but she’s just too excited to eat. [Nathan]’s latest solution is to launch the food piece by piece using a catapult. The dog loves the gamified feeding method, which is sort of like one-way fetch. She gets a bit of exercise, and everyone is amused for the half hour it takes to fling 1.5 cups of food one piece at a time.

Electronics-wise, this food flinger doesn’t use much more than three servos and an Arduino Uno. Servo #1 pulls the arm back until it hits a limit switch. Servo #2 holds the arm down , and servo #3 rotates the food tube until it drops a unit of kibble into the spoon. Then servo #2 lets the arm go, and the tasty morsel flies about 30 feet (10 meters).

[Nathan] doesn’t offer step-by-step instructions, but there is more than enough detail to replicate this project. He used what he had on hand, such as scrap aluminium from another project for the frame. Future plans include swapping out the 6V lantern battery for rechargeable AAs, and downsizing to a Nano. We’ve fetched a couple of videos for you and thrown them in after the break. Go get ’em, reader!

Pets need plenty of water, especially during the summer. Here’s a no-sweat automatic watering solution we saw a few years ago.



  • Newsletter

    Sign up for the PlanetArduino Newsletter, which delivers the most popular articles via e-mail to your inbox every week. Just fill in the information below and submit.

  • Like Us on Facebook