Creepy Halloween Doll Might Make You Betsy Wetsy

If you want to terrify your neighborhood this Halloween, you might go for the old standbys like skeletons or zombies. But you don’t have to go gory to find glory. Consider the talking doll. Those things are creepy enough already, right? Well, [cabuu] says no, the doll should be animated with servos and have remote control. She should still be able to talk, just not when you expect her to.

Forget pushing on her stomach, ’cause Baby’s got a Wemos D1 mini and her own Blynk app now.  A set of sliders in the app control a micro servo that animates her eyes, and another servo that twists her head from side to side. Her head doesn’t go all the way ’round, but that’s probably for the best. There are preset fright modes [cabuu] can set and forget until she springs to life via motion sensor.

We particularly like the bracket [cabuu] designed and printed that joins the eyeballs with the servo, along with his clever use of printed mate brackets to hold the servos in place within the head. If you think you can stomach it, there’s a demo video after the break. Stay tuned for total doll dissection after that as [cabuu] builds and inserts the terrifying tidbits.

We love hacks that combine innocence with insanity. Have you ever seen Thomas the Tank Engine singing Rick Astley?

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Pneumatic Zombie Will Blow Away Trick-or-Treaters

What are you doing for Halloween this year? Just gonna set the candy bowl out on the porch and call it good? That’s a risky one, ’cause if one group of mischievous preteens cleans you out, you might get TP’d by the next one. Best to keep Halloween a tad on the scary side and keep those ghouls in line. Candy is a privilege, not a right.

Halloween is a big deal in [trimbandit]’s little burg, and he builds a new attraction for the front yard every year. This year, it’s the dawn of the dead — a fresh zombie rising jerkily from the grave to say hello, world. He moves left, he moves right, he writhes and wrestles, wedged between worlds.

His life force comes from a pneumatic system designed for props. The cylinders connect to a controller with built-in relays that makes programming frightfully easy. Then it was just a matter of adding a foam head, skinning it with a scary mask, and fitting him for a suit from Goodwill. Drag yourself and your candy bucket past the break for a fun-size demo video and a couple of bonus goodies.

We bet [trimbandit] is already wondering how to step up his game for next year. He seems to have conquered the ground, so why not take to the skies for fright and delight?

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Next Level Spirit Level Is On The Level

Miss your shot and scratch on the eight ball? It’s natural to blame the table for not being level so you can save face, but in all likelihood, you’re probably right. [Huygens Optics]’s father never misses a billiards shot on his home table, until one day he did. [Huygens Optics] rushed to his aid and built an extremely precise spirit level for the table so it will never happen again.

First and foremost, he had to decide how sensitive the spirit level should be. Obviously, the table should be as level as possible, though other factors like the condition of the felt will come into play as well. In doing some calculations, he found that every degree of leveling error in the table translates to several millimeters of ball unevenness and deviation, so he wanted the level to have .01 degrees of accuracy. How he manages this feat of grinding and polishing in a hobbyist workshop is all captured in the fascinating video after the break.

The level is made from two disks cut from leftover 15mm borosilicate glass. Between the disks is a 4mm cavity for the liquid (ethyl alcohol) and the air bubble to move around. To avoid introducing error with uneven adhesive application, [Huygens Optics] tried to join the disks using optical contact bonding, wherein two surfaces stick together through the magic of intermolecular forces, like the one that keeps geckos attached to vertical things. That worked quite well until he added the liquid, which broke the bond. Instead, he used a thin, UV-curable epoxy.

Getting into optics doesn’t have to cost a lot. Instead of buying or grinding lenses for experimentation, you can laser-cut lens profiles out of acrylic.

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Open-Source Arm Puts Robotics Within Reach

In November 2017, we showed you [Chris Annin]’s open-source 6-DOF robot arm. Since then he’s been improving the arm and making it more accessible for anyone who doesn’t get to play with industrial robots all day at work. The biggest improvement is that AR2 had a closed-loop control system, and AR3 is open-loop. If something bumps the arm or it crashes, the bot will recover its previous position automatically. It also auto-calibrates itself using limit switches.

AR3 is designed to be milled from aluminium or entirely 3D printed. The motors and encoders are controlled with a Teensy 3.5, while an Arduino Mega handles I/O, the grippers, and the servos. In the demo video after the break, [Chris] shows off AR3’s impressive control after a brief robotic ballet in which two AR3s move in hypnotizing unison.

[Chris] set up a site with the code, his control software, and all the STL files. He also has tutorial videos for programming and calibrating, and wrote an extremely detailed assembly manual. Between the site and the community already in place from AR2, anyone with enough time, money and determination could probably build one. Check out [Chris]’ playlist of AR2 builds — people are using them for photography, welding, and serving ice cream. Did you build an AR2? The good news is that AR3 is completely backward-compatible.

The AR3’s grippers work well, as you’ll see in the video. If you need a softer touch, try emulating an octopus tentacle.

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Fortified Feeder For Feral Felines

Most of the commercially-available pet feeders littering the internet are cheaply-made, with wimpy motors and infuriating interfaces. Want to use it outdoors? Good luck. If you need a heavy-duty, outdoor cat feeder, you gotta heat up your soldering iron and do it yourself.

[jplanaux] is under contract to feed a bunch of feral cats that hang around, but he’s often gone for weeks at a time. His two-feeder fail-over system has one weak link, and it’s these commercial feeders — they’re under-powered and just plain unreliable, even after modding them for Raspi control. What he needed was an industrial strength automatic feeder that’s completely customized for his situation.

A simple web interface lets him set up automatic feeding times, or push kibble on demand if customers show up and there’s no food. The system takes pictures of the bowl to verify that food came out and was subsequently eaten. It’s supposed to be racoon-proof, so [jplanaux] can see who or what is chowing down. Aside from that, the feeder is pretty standard, with a large hopper on top of a screw drive that’s driven by a NEMA17. The stepper is relay-driven, so it only uses power when it’s driving the screw.

[jplanaux] has the STL files and code available, and even designed a bowl and base extension for people who want to build one and use it indoors. Nibble at the kibble-sized demo video after the break.

The lion’s share of the auto-feeder builds we chew on around here are designed for dry food. Serving wet food is a much harder problem, but is definitely possible to pull off.

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Dip Your Toes In The Open Water Of Raspipool

If you’re lucky enough to have a swimming pool, well, you may not feel all that lucky. Pools are great to have on a hot summer day, but keeping them crystal clear and pH-balanced is a deep dive into tedium. Sure, there are existing systems out there. They cost a kiddie pool of cash and are usually limited to particular pool parts. Existing DIY solutions are almost as bad, and so [segalion] is making waves with a dumb, brand-agnostic pool automation system called Raspipool.

Sensors for pH, ORP, and temperature are immersed in pool water flowing through a bypass pipe that runs between the filter and the pump. The basic plan is to control the pumps and sensors with a web-enabled Raspberry Pi, and have the Pi send action and threshold notifications straight to [segalion]’s poolside lounge chair. Each piece is dedicated to a single task, which allows for easy customization and future expansion.

[segalion] is trying to get more people involved so that Raspipool can keep really make a splash. Be sure to check out the project wiki and let him know if you can help or have suggestions.

We’re glad [segalion] is building from the ground up, and doesn’t have to dive into some pre-existing mess of an automation system.

Captivating Clock Tells Time With Tall Tubes

Time is probably our most important social construct. Our perception of passing time changes with everything we do, and when it comes down to it, time is all we really have. You can choose to use it wisely, or sit back and watch it go by. If you want to do both, build a clock like this one, and spectate in sleek, sophisticated style.

[ChristineNZ]’s mid-century-meets-steampunk clock uses eight ILC1-1/8Ls, which are quite possibly the largest VFD tubes ever produced (and still available as new-old stock). In addition to the time, it displays the date, relative humidity, and temperature in both Celsius and Fahrenheit. A delightful chime sounds every fifteen minutes to remind you that time’s a-wastin’.

The seconds slip by in HH/MM/SS format, each division separated by a tube dedicated to dancing the time away. The mesmerizing display is driven by an Arduino Mega and a MAX6921 VFD driver, and built into a mahogany frame. There isn’t a single PCB in sight except for the Mega — all the VFDs are mounted on wood and everything is wired point-to-point. Sweep past the break to see the progressive slideshow build video that ends with a demo of all the functions.

Those glowing blue-green displays aren’t limited to clocking time. They can replace LCDs, or be scrolling marquees.

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