Switch Tester Servo-Slaps Them ’til They Fail

June 23, 2020 by Kristina Panos 33 Comments

[James] is designing an open-source 3D printed keyboard switch, with the end goal of building a keyboard with as many printed parts as possible. Since keyswitches are meant to be pressed quite often, the DIY switches ought to be tested just as rigorously as their commercial counterparts are at the factory. Maybe even more so.

The broken spring after 13,000+ automated boings.

Rather than wear out his fingers with millions of actuations, [James] built a robot to test switches until they fail. All he has to do is plug a switch in, and the servo-driven finger slowly presses the slider down until the contacts close, which lights the LED.

The system waits 100ms for the contacts to stop any tiny vibrations before releasing the slider. That Arduino on the side tracks the contact and release points and sends them to the PC to be graphed. If the switch fails to actuate or release, the tester stops altogether.

We love that this auto-tester works just fine for commercial switches, too — the bit that holds the switch is separate and attaches with screws, so you could have one for every footprint variant. [James] recently did his first test of a printed switch and it survived an astonishing 13,907 presses before the printed coil spring snapped.

One could argue that this doubles as a servo tester. If you want a dedicated device for that, this one can test up to sixteen at a time.

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Resistors Sorter Measures Values

May 23, 2020 by Al Williams 22 Comments

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.

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Animatronics Hack Chat

May 18, 2020 by Dan Maloney 4 Comments

Join us on Wednesday, May 20 at noon Pacific for the Animatronics Hack Chat with Will Cogley!

While robots have only a made a comparatively recent appearance on the technology timeline, people have been building mechanical simulations of living organisms for a long time indeed. For proof, one needs only to look back at the automatons built by clever craftsmen to amuse and delight their kings and queens. The clockwork mechanisms that powered fanciful birds and animals gave way to the sophisticated dolls and mannequins that could perform complex tasks like writing and performing music, all with the goal of creating something that looked and acted like it was alive.

Once the age of electronics came around, the springs that drove the early automatons and the cams that programmed their actions were replaced by motors and control circuits. New materials made once-clunky mechanisms finer and more precise, sensors and servos made movements more lifelike, and the age of animatronics was born.

Animatronics have since become a huge business, mostly in the entertainment industry. From robotic presidents to anachronistic dinosaurs to singing rodents designed to sell pizza, animatronics have been alternately entertaining and terrifying us for decades. The fact that they’re not “real” robots doesn’t make the melding of mechanical, electrical, and computer systems into a convincing representation of a real being any less challenging. Will Cogley has more than a few amazing animatronic designs under his belt, some of which we’ve featured on Hackaday. From hearts to hands to slightly terrifying mouths, Will puts a ton of work into his mechanisms, and he’ll stop by the Hack Chat to tell us all about designing and building animatronics.

Our Hack Chats are live community events in the Hackaday.io Hack Chat group messaging. This week we’ll be sitting down on Wednesday, May 20 at 12:00 PM Pacific time. If time zones have got you down, we have a handy time zone converter.

Click that speech bubble to the right, and you’ll be taken directly to the Hack Chat group on Hackaday.io. You don’t have to wait until Wednesday; join whenever you want and you can see what the community is talking about.

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Piston-Powered Pellet Pusher For Peckish Pets

May 14, 2020 by Kristina Panos 2 Comments

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.

Alexa, Shoot Me Some Chocolate

May 11, 2020 by Kristina Panos 10 Comments

[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.

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Nightmare Fuel Telepresence ‘Bot May Become Your Last Friend

May 9, 2020 by Kristina Panos 15 Comments

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.

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Open Laser Blaster Shells Out More Bang For The Buck

May 8, 2020 by Kristina Panos 5 Comments

[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.

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