The Secrets Of The Pop Pop Boat

June 13, 2022 by Adam Fabio 28 Comments

Many kids get an early introduction to mechanics with tin pop-pop boats. If you haven’t played with one – you’re missing out! Pop Pop boats are fun toys – but how they work is often misunderstood. To clear this up, [Steve Mould] takes a deep dive into the theory of operation of the pop pop boat.

Most people think these toys operate like a simple steam engine, with water being flashed into steam inside a tiny tin boiler. Turns out that’s not the case. To explain the physics, [Steve] commissioned a glass version of the boat.

The glass boat shows that during normal operation, there isn’t any water at all in the “boiler” at all. The water is only in the boat’s small exhaust tubes. The air inside the tank is heated by a candle. The air expands and pushes the water out of the tubes. This allows the air to cool, and return to the tank. The water then rushes back up the tubes, and the process repeats.

One of the more interesting facts of the video is that the glass boat doesn’t pop. The popping sound associated with the boat is actually made by the tin diaphragm on top of the “boiler”.

[Steve] has gotten pretty good at explaining complex topics using clear cutaway models. If this tickles your fancy, check out his water computer.

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Autogyro Models Are Hard — Even For [Peter Sripol]

May 9, 2022 by Adam Fabio 12 Comments

Aviation consists of two major groups. Airplane enthusiasts, and helicopter enthusiasts. The two groups rarely get along, each extolling the virtues of their chosen craft. Somewhere in between are autogyro folks. People who like vehicles that blend the best (or worst) of both airplanes and helicopters. Aviation master [Peter Sripol] has dipped his toes into the autogyro world, but not without some trouble.

Autogyros are propelled by a propeller, like a plane. They also have a tail section that works similar to a fixed-wing aircraft. That’s where the similarities end though. Lift for autogyros comes in the form of a rotating set of blades, much like a helicopter. Autogyro rotors aren’t powered during flight. They utilize autorotation. The blades freewheel, spun by the air as the craft moves forward.

[Peter] recently got his hands on a full-scale autogyro. So it made sense to build a model to help learn to fly. This isn’t [Peter’s] first attempt with autogyro models. He’s built a few in the past, with limited success. This time he started from scratch and ran into even more problems!

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Verbot Goes To The Dark Side

May 9, 2022 by Adam Fabio 14 Comments

What happens to old, neglected 1980s toy robots? According to the [Randi Rain], they turn to the dark side! Way back in the ’80s, Tomy had an entire line of robots — from keychain wind-up toys to rolling, talking machines almost 2 feet tall. Tucked into the middle of this line was Verbot. Verbot’s claim to fame is that it is a voice-controlled robot. More than that, it was speaker-dependent. Train the robot with commands like “go forward” and then watch as it responds to your every command.

As you might guess, the speech recognition wasn’t great by today’s standards. Recognition was handled by a Microcontroller — a Mitsubishi product that was possibly a mask programmed 8051 variant. Pretty novel for an 80s toy — in fact, there’s a patent for it.

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Engineering On A Deadline For Squid Game

April 14, 2022 by Adam Fabio 35 Comments

If you asked us for an epic tale of designing and building under a deadline, one of the last places we would think to look is a MrBeast video. Yet here we are, thanks in no small part to the epic skills of one [William Osman].

What do you do when a major YouTube celebrity asks you to handle a project with an impossible deadline? If you’re [William], you say “heck yeah” and figure out the details later. In this case, it was famed YouTuber [Jimmy Donaldson], aka MrBeast, who was planning his own version of Squid Game. In this version, no one dies, but a few players do walk away with a lot of cash.

The premise is simple — “kill” people with a motion-sensing gun turret, just like the one in the show. The problem is that the show had all the tools of movie magic – multiple takes, video editing, you name it. [William] was tasked with handling a live event, with 456 real people, and no do-overs. Oh, and the whole thing had to be ready in 3 weeks.

The kills had to be pretty obvious too – we’re talking simulated blood squirting everywhere. So [William] decided to build his own version of a blood squib – the device Hollywood has used for decades to simulate bullet wounds. Initial work with pneumatic systems proved to be impractical. That’s when he put on his manager hat — and hired people to solve the problem for him. You might recognize a few of them — [Allen Pan] makes an appearance, as well as chemical genius [NileRed]. Even [TheBackYardScientist] shows up.

The video documents [William]’s journey, getting 500 copies of a board built and delivered on deadline. As such, there isn’t a ton of detail about the internal workings of the system. A pair of AA batteries feed into a boost converter, which powers an ESP8266 inside an ESP-WROOM-02 module. The ESP drives a few LEDs and a MOSFET. The MOSFET is connected to the star of the show – an MGJ firewire initiator – think of it as a model rocket igniter on steroids. The initiator hides behind a bag of YouTube-friendly yellow “blood”. When the system is commanded to kill, the initiator pops the bag, spraying blood everywhere.

Doing this for one device isn’t so bad, but we’re following Squid Game rules – which means 456 competitors. Further, there were 100 iPhones loaded with a custom kill app for the workers. Add a central server into the mix, and you’ve got 557 devices in close quarters basting on 2.4 GHz and 5.8 GHz. Did we mention that [William] had never done a test with more than a handful of devices?

Want to find out what happens? Check out the video below!

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Curious Marc Takes On Sewing Machine Repair

November 4, 2021 by Adam Fabio 29 Comments

Even the most talented engineers can be stymied by simple repair projects. In this case, repairing a broken sewing machine has [CuriousMarc] all tangled up. [Marc] is probably best known as a part of the team who managed to restore and boot up an apollo guidance computer, but he’s worked with plenty of other vintage machines.

This problem hit much closer to home. [Marc’s] daughter wanted to sew a Halloween costume. The machine would boot up fine, but when attempting to sew, it would make a bit of noise, then beep and display “The safety device has been activated”. Not very helpful.

The sewing machine in question is called “Baby Lock Decorator’s Choice” and is manufactured by Brother for Juken. [Marc] of course dug in, and quickly found himself stymied by a clamshell case that just didn’t want to come apart. This is the point where many of us would apply just a little too much force when prying and be rewarded with a broken case.

[CuriuosMarc] is thankfully the more patient sort. Rather than become [FuriousMarc], he carefully persevered to find a hidden screw holding things together. The screw could only be accessed by inserting a screwdriver through a tiny access hole on the front chassis of the machine.
With the screw out, a couple of molded clips were all that held the case sides together. After popping them, [Marc] was finally able to fix the real problem: A toothed belt that had slipped off its cog. That’s it — just a loose belt. The cryptic error code most likely was due to the machine realizing it the motor was on, but the machine wasn’t moving – which would generally indicate something stuck or tangled in the thread path.

This type of repair would be much easier if service manuals were readily available. We did a quick search for this model but didn’t find anything freely available.

Have you gotten stuck by a simple repair? Tell us about it down in the comments.

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Janksy Robot Paints Murals One Dot At A Time

November 2, 2021 by Adam Fabio 22 Comments

[Stuff Made Here] has a new shop, with a huge blank wall. A blank white wall just wouldn’t do, so rather than paint the wall himself, he designed a robot to do it for him. (Video, embedded below.)

The result is Janksy. A huge machine made of metal, wood, and 3D printed parts. Janksy is an ingenious design in that it has two sets of X and Y axis. A large, slow-moving system of rails and cables positions the robot roughly in the right area of the wall. From there a much smaller, but faster and more precise motion system makes the final moves.

The “business end” of Janksy is of course a paint sprayer; in this case a Harbor Freight model. The medium of choice is acrylic paint, as Janksy will be painting for several days, and didn’t want to gas himself with the volatile solvents of more traditional paints.

Janksy mainly sprays dots of paint. Up close you’ll only see the dots, but step back a bit and a full image takes shape. It’s a technique called Pointillism, which puts Janksy in the company of artists like Georges Seurat and
Vincent van Gogh.

While human artists mix colors to produce the hue they want, robots can’t easily do that. [Stuff Made Here] spends quite a bit of time explaining basic color theory, and how dots of cyan, magenta, and yellow will combine in the eye to produce colors – much the way a monitor uses pixels of red, green, and blue light.

After all this work, you might be wondering what [Stuff Made Here] would want on his wall. Well, let’s just say that he loves his wife, even though his pranks on here often elicit an exasperated glare. Watch the video after the break for the full story.

You don’t have to build a huge drawing robot though – we’ve seen some great plotters on a much smaller scale, including one that will play tic-tac-toe.

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Fail Of The Week: Alternator Powered Electric Go-Kart Doesn’t Go

October 25, 2021 by Adam Fabio 21 Comments

What do you give a six-year-old who loves going fast but doesn’t like loud noises? Convert a gas go-kart to electric of course! (Video, embedded below.) That goal started [Robert Dunn] of Aging Wheels down a long path toward a go-kart that almost, but doesn’t quite… work.

If you’ve watched any of [Robert’s] videos, you know he doesn’t take the easy path. The man owns a Trabant and Reliant Robin after all. Rather than buy a battery pack, he built his own 5S24P pack from individual LiFePO4 cells. Those cells generally are spot welded, so [Robert] built an Arduino-controlled heirloom-quality spot welder. Now while the welder could handle thin nickel strips, it wasn’t up the task of welding high current nickel-plated copper. When attempts at a solution failed, [Robert] built a system of clamped copper bus bars to handle the high current connections for the batteries.

If batteries weren’t hard enough, [Robert] also decided he wasn’t going to use an off-the-shelf motor for this project. He converted a car alternator to operate as a brushless motor. We’ve covered projects using this sort of conversion before. Our own [Jenny List] even wrote a tutorial on it. [Robert] unfortunately has had no end of trouble with his build.

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