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Archive for the ‘servo’ Category

We’ve all been there. A big bag of resistors all mixed up. Maybe you bought them cheap. Maybe your neatly organized drawers spilled. Of course, you can excruciatingly read the color codes one by one. Or use a meter. But either way, it is a tedious job. [Ishann’s] solution was to build an automatic sorter that directly measures the value using a voltage divider, rather than rely on machine vision as is often the case in these projects. That means it could be modified to do matching for precise circuits (e.g., sort out resistors all marked 1K that are more than a half-percent away from one nominal value).

There is a funnel that admits one resistor at a time into a test area where it is measured. A plate at the bottom rotates depending on the measured value. In the current implementation, the resistor either falls to the left or the right. It wouldn’t be hard to make a rotating tray with compartments for different values of resistance. It looks like you have to feed the machine one resistor at a time, and automating that sounds like a trick considering how jumbled loose axial components can be. Still, its a fun project that you probably have all the parts to make.

An Arduino powers the thing. An LCD screen and display control the action. If you want some practice handling material robotically, this is a great use of servos and gravity and it does serve a practical purpose.

We have seen many variations on this, including ones that read the color code. If you ever wanted to know where the color code for resistors came from, we took a trip to the past to find out earlier this year.

We all have our new and interesting challenges in lockdown life. If you’ve had to relocate to ride it out, the chances are good that even your challenges have challenges. Lockdown left [Kanoah]’s sister in the lurch when it came to feeding her recently-adopted pet rat, so he came up with a temporary solution to ensure that the rat never misses a meal.

Most of the automated pet feeders we see around here use an auger to move the food. That’s all fine and good, but if you just need to move a singular mass, the screw seems like overkill. [Kanoah]’s feeder is more akin to a pellet-pushing piston. It runs on a Metro Mini, but an Arduino Nano or anything with enough I/O pins would work just fine. The microcontroller starts counting the hours as soon as it has power, and delivers pellets four times a day with a servo-driven piston arm. [Kanoah] has all the files up on Thingiverse if you need a similar solution.

There many ways of solving the problem of dry pet food delivery. Wet food is a completely different animal, but as it turns out, not impossible to automate.

[Harrison] has been busy finding the sweeter side of quarantine by building a voice-controlled, face-tracking M&M launcher. Not only does this carefully-designed candy launcher have control over the angle, direction, and velocity of its ammunition, it also locates and locks on to targets by itself.

Here comes the science: [Harrison] tricked Alexa into thinking the Raspberry Pi inside the machine is a smart TV named [Chocolate]. He just tells an Echo to increase the volume by however many candy-colored projectiles he wants launched at his face. Simply knowing the secret language isn’t enough, though. Thanks to a little face-based security, you pretty much have to be [Harrison] or his doppelgänger to get any candy.

The Pi takes a picture, looks for faces, and rotates the turret base in that direction using three servos driven by Arduino Nanos. Then the Pi does facial landmark detection to find the target’s mouth hole before calculating the perfect parabola and firing. As [Harrison] notes in the excellent build video below, this machine uses a flywheel driven by a DC motor instead of being spring-loaded. M&Ms travel a short distance from the chute and hit a flexible, spinning disc that flings them like a pitching machine.

We would understand if you didn’t want your face involved in a build with Alexa. It’s okay — you can still have a voice-controlled candy cannon.

After this pandemic thing is all said and done, historians will look back on this period from many different perspectives. The one we’re most interested in of course will concern the creativity that flourished in the petri dish of anxiety, stress, and boredom that have come as unwanted side dishes to stay-at-home orders.

[Hunter Irving] and his brother were really missing their friends, so they held a very exclusive hackathon and built a terrifying telepresence robot that looks like a mash-up of Wilson from Castaway and that swirly-cheeked tricycle-riding thing from the Saw movies. Oh, and to make things even worse, it’s made of glow-in-the-dark PLA.

Now when they video chat with friends, TELEBOT is there to make it feel as though that person is in the room with them. The Arduino Uno behind its servo-manipulated vintage doll eyes uses the friend’s voice input to control the wind-up teeth based on their volume levels. As you might imagine, their friends had some uncanny valley issues with TELEBOT, so they printed a set of tiny hats that actually do kind of make it all better. Check out the build/demo video after the break if you think you can handle it.

Not creepy enough for you? Try building your own eyes from the ground up.

 

[a-RN-au-D] was looking for something fun to do with his son and dreamed up a laser blaster game that ought to put him in the running for father of the year. It was originally just going to be made of cardboard, but you know how these things go. We’re happy the design went this far, because that blaster looks fantastic.

Both the blaster and the target run on Arduino Nanos. There’s a 5mW laser module in the blaster, and a speaker for playing the pew pew-related sounds of your choice. Fire away on the blaster button, and the laser hits a light-dependent resistor mounted in the middle of the target. When the target registers a hit, it swings backward on a 9g servo and then returns quickly to vertical for the next shot.

There are some less obvious features that really make this game a hit. The blaster can run in 10-shooter mode (or 6, or whatever you change it to in the code) with a built-in reload delay, or it can be set to fully automatic. If you’re short on space or just get sick of moving the target to different flat surfaces, it can be mounted on the wall instead — the target moves forward when hit and then resets back to flat. Check out the demo video we loaded up after the break.

No printer? No problem — here’s a Node-RED shooting gallery that uses simple wooden targets.

Sundials, one of humanity’s oldest ways of telling time, are typically permanent installations. The very good reason for this is that telling time by the sun with any degree of accuracy requires two-dimensional calibration — once for cardinal direction, and the other for local latitude.

[poblocki1982] is an amateur astronomer and semi-professional sundial enthusiast who took the time to make a self-calibrating equatorial ‘dial that can be used anywhere the sun shines. All this solar beauty needs is a level surface and a few seconds to find its bearings.

Switch it on, set it down, and the sundial spins around on a continuous-rotation servo until the HMC5883L compass module finds the north-south orientation. Then the GPS module determines the latitude, and a 180° servo pans the plate until it finds the ideal position. Everything is controlled with an Arduino Nano and runs on a 9V battery, although we’d love to see it run on solar power someday. Or would that be flying too close to the sun? Check out how fast this thing calibrates itself in the short demo after the break.

Not quite portable enough for you? Here’s a reverse sundial you wear on your wrist.

When [Taste the Code] saw that his YouTube channel was approaching 1,000 subscribers, it was time to do something special. But celebration is no reason to be wasteful. This flag-waving celebratory hat has endless possibilities for the future.

The build is simple, which is just right for these strange times of scarcity. An Arduino Uno hot-glued to the back of the hat is directly driving a pair of 9g servos on the front. [Taste the Code] made the flags by sticking two stickers back to back with a bamboo skewer in between. The code is flavored such that the flags will wave in one of three randomly-chosen patterns — swing around, swing in reverse, and wild gesticulations.

After the novelty of the whole 1k subs thing wears off, [Taste the Code] can change the flags over to Jolly Rogers to help with social distancing. And someday in the future when things are really looking up, they can be changed over to SARS-CoV-2 victory flags, or fly the colors of a local sports team. We think it would be way cool to program some kind of real semaphore message into the flags, though the mobility might be too limited for that. Check out the build video after the break, which happens picture-in-picture as [Taste the Code] dishes out a channel retrospective and lays out a course for the future.

Even though YouTube messed with subscriber counts, we think it’s still worth making a cool counter. Here’s one with a Tetris twist.

Good clocks are generally those that keep time well. But we think the mark of a great clock is one that can lure the observer into watching time pass. It doesn’t really matter how technical a timepiece is — watching sand shimmy through an hourglass has its merits, too. But just when we were sure that there was nothing new to be done in the realm of 7-segment clocks, [thediylife] said ‘hold my beer’ and produced this beauty.

A total of 28 servos are used to independently control four displays’ worth of 3D-printed segments. The servos pivot each segment back and forth 90° between two points: upward and flat-faced to display the time when called upon, and then down on its side to rest while its not needed.

Circuit-wise, the clock’s not all that complicated, though it certainly looks like a time-consuming build. The servos are controlled by an Arduino through a pair of 16-channel servo drivers, divided up by HH and MM segments. The Arduino fetches the time from a DS1302 RTC module and splits the result up into four-digit time. Code-wise, each digit gets its own array, which stores the active and inactive positions for each servo. Demo and full explanation of the build and code are waiting after the break.

When it comes to 7-segment displays, we say the more the merrier. Here’s a clock that uses pretty much all of them.

Some projects are all-around simple, such as the lemon battery or the potato clock. Other projects are rooted in simple ideas, but their design and execution elevates them to another level. [Sharathnaik]’s heart visualizer may not be all that electronically complex, but the execution is pulse-pounding.

The closest that most of us will get to seeing our own heartbeat is watching the skin twitch in our neck or wrist. You know that your heart doing the work of keeping you alive, but it’s hard to appreciate how it exerts itself. With just a few components and printed parts, the heart’s pumping action comes to life as your pulse drives single-x scissor mechanisms to push and pull the plastic plates.

This heart visualizer isn’t nearly as complex as the organ it models, and it’s an easy build for anyone just starting out in electronics. Put your finger on the heart rate sensor in the base, and an Arduino Nano actuates a single servo to your own personal beat. We’d love to see it work overtime while someone gets worked up. For now, there’s an even-tempered demo after the break, followed by an assembly video.

Heartbeat sensing can be romantic, too. Here’s a lovely circuit sculpture that runs at the rate of the receiver.

How much easier would life be if you could just grab hold of whatever mechanism you wanted to manipulate, move it like you want, and then have it imitate your movements exactly? What if you could give a servo MIDI-like commands that tell it to move to a certain location for a specific duration? Wonder no more, because [peterbiglab] has big-brained the idea into fruition.

With just one wire, an Arduino, and some really neat code, [peter] can get this servo to do whatever he wants. First he tells the Arduino the desired duration in frames per second. Then he grabs the horn and moves it around however he wants — it can even handle different speeds. The servo records and then mimics the movements just as they were made.

The whole operation is way simpler than you might think. As [peterbiglab] demonstrates in the video after the break, the servo knows its position thanks to an internal potentiometer on the motor’s rotor. If you locate the pot output pin on the control board and run a wire from there into an Arduino, you can use that information to calibrate and control the servo’s position pretty easily. There are a ton of possibilities for this kind of control. What would you do with it? Let us know in the comments.

If you want to try this with a bunch of servos at once, might as well build yourself a little testing console.

Via r/duino



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