Toy Hacks

1061 Articles

Fixing A 1990s LEGO Electric Train Speed Regulator

September 8, 2026 by 15 Comments

Before LEGO train sets moved to battery-powered locomotives with plastic rails, all of them worked pretty much like any other train set of the era. This meant metal rails that the locomotive’s wheels would use to pick up power from and a central controller that would inject said power and also regulate the train’s speed and direction. The LEGO 2868b Electric Train Speed Regulator is one such example, and [Nonsense Wars] recently had one under the knife to repair it.

The single PCB inside is quite straightforward, with the 9-12 VAC supply input from an external power adapter, and a variable voltage regulator that sees its target voltage switched by a bank of resistors.

It are these resistors that the big yellow control switches between when you operate it, changing the output voltage and also output polarity you cross the midway point. Effectively this means that there is just one non-passive component on the PCB, in the form of the TO-220 package strapped to the big heatsink.

In this particular unit it was found to be a Fairchild KA317, which is for all intents and purposes here the same as an LM317T. One quick swap later and this controller was back in business like it was 1995.

Compared to the engineering crammed into a modern “smart brick”, things really have come quite a ways in the world of LEGO.

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Disassembling A Mini Air Blower To Make RC Airplanes

September 8, 2026 by 22 Comments

As a certified RC airplane fan, the [RCMakerLab] on YouTube found themselves looking at one of those nifty mini air blowers that provide an alternative to a compressor and canned air for dusting and other high-volume, high-pressure air-related tasks.

Inside these quite affordable units is a ducted fan (EDF) that can produce fairly high levels of airflow to get to every last dust bunny hiding on a PCB or inside a keyboard, raising the question of whether you could use these to fly a model airplane with.

As can be seen in the torn down unit, there isn’t a lot to these air blowers, with the ESC bolted onto the EDF and only the speed regulator and on/off switch being external controls. This would make it very easy to integrate into an airplane, but leaves the question of whether it can generate enough thrust to make it worth the effort.

Using a custom rig, it was shown to generate up to 110 grams of thrust with a current of 16.5 A, which would at least go a long way to carrying its own battery pack. In order to create an airplane with it, probably two of these motors are needed. There’s also the potential of reducing weight by changing the ESC and such, making reusing these little EDFs from any discarded or broken mini air blowers at least worth a shot.

At the very least, it seems like it has a better shot of working than a plane powered by an electric leaf blower.

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A small rocket is shown launching into the sky, with a trail of smoke leading into the mount of a black pipe. Four large plastic pieces are falling away from below the rocket.

Tube Launch Boosts Rocket’s Performance

September 3, 2026 by 18 Comments

If you want improve a model rocket’s performance, all the common options come with serious trade-offs: you could increase the motor’s size, which raises safety issues, or you could cut down on weight, which limits the possible payload. [Con Hathy] was therefore intrigued by the design of the Arcas sounding rockets, which with the aid of a gas-fed launch tube could reach an altitude of 100 km. Even in models without a gas generator, a launch tube apparently boosted performance, an effect which [Con] was able to replicate in a much smaller model rocket.

In theory, as the rocket engine fires, it should pressurize the tube behind the rocket, providing an extra boost out of the tube. To test this, [Con] 3D printed a test rocket, launched it both from a standard rail and from a tube, and compared the results. During tube launches, a printed sabot fit around the rocket and formed a seal with the launch tube. The results were surprising: the tube-launched rocket actually performed substantially worse than a rail launch. After building a simulation, [Con] found that, as the rocket moves down the tube, the volume of tube it needs to back-fill with gas increases faster than the engine puts out exhaust; it was pulling a slight vacuum behind it, slowing itself down.

To solve this, [Con] decreased the diameter of the launch tube. To let the rocket fit into the tube, he also modified it to use pop-out stabilizer fins which wrap around the rocket while in the tube. The sabot was also shrunk, and had foam added to improve the seal between it and the rocket. For this second test, [Con] also connected a pressure sensor to the base of the launch tube. The results on the second launch were much better: according to an altimeter, it managed to fly 72% higher. Based on the pressure sensor’s data, a longer tube could have squeezed out still more performance, but this still demonstrated the principle quite well.

We’ve seen a tube-launched rocket before, though not with such a performance focus.

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Radio Shack Toy Returns To Life

August 15, 2026 by 24 Comments

[The Modern Rogue] found an old childhood friend in a closet: a Radio Shack 200-in-1 electronic kit. Along with [Josh Nass], he put it through its paces and made a few repairs along the way. As you might expect, the batteries had long ago leaked out their magic juice.

If you missed these, they were a host of real electronic components with springs connected to the leads. To make a circuit, you bend the spring over, insert a wire, and let go of the spring. By changing the wiring, you could make radios, alarms, computer circuits, and more

There were dozens of these kits, some more capable than others. This was a particularly nice one with a loaded front panel and several exotic components. In the end, they made a code practice oscillator, and it worked.

While you can’t find kits exactly like these anymore, you can make your own. Or try Snap Circuits and print your own modules. You take solderless breadboards for granted today, but they haven’t always been around or affordable.

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Turning A Toy Game Boy Into A Real Game Boy

August 11, 2026 by 4 Comments

In the world of children’s toys there are many offerings which are meant to look like devices used by older kids or even adults, with the Fisher Price Laugh & Learn Lil’ Gamer toy bearing quite the resemblance to Nintendo’s iconic Game Boy. Although this factoid could be filed away as amusing trivia before passing said toy to a child for its requisite physical abuse by said child, a purported adult can still have a lot of fun with this toy by modding it into a real Game Boy, as [KOUZEX] recently did.

Part of the challenge here is to not just treat it as an unconventional replacement shell for a genuine Game Boy, but to retain as much of the child toy’s look and feel as possible. This includes things like buttons and even the weird sliding blocks on the side.

For the functional components a Game Boy Color with a busted screen was chosen as a donor, with the GBC mainboard fitting almost perfectly inside its new shell. Wires were then soldered to bridge Nintendo’s PCB with the toy’s PCB to make the original buttons and speaker work. After blowing a fuse on the GBC mainboard due to likely some power back feeding, the toy’s PCB had its non-essential parts stripped, but fortunately without further damage to the grafted in electronics.

Most of this mod is quite straightforward, just with some creativity required to add a Select and Start button as these were notably absent from the original. The new, rather large replacement OLED screen is a nice upgrade too and actually fits pretty well with the chunky look of the child’s toy. Even as mostly a joke mod, it seems surprisingly functional.

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RC Telemetry Board Lets Virtual Crewmember Help You Race Better

July 30, 2026 by 3 Comments

Logging and telemetry in remote controlled racing is a great thing, and not only does [jwachlin]’s Open RC Spotter do a fantastic job of that, it has quite a few clever tricks up its sleeve that make it extra special.

Open RC Spotter is an ESP32-based hardware platform for high performance RC car racing that reads from various sensors (including IMU, GPS, temperature, battery, and IR receiver for IR lap beacons) to create a filtered stream of readings that include position, velocity, lap time, battery voltage, and more.

Got RC car telemetry? Feed it to a virtual race engineer for real-time feedback.

This data gets logged to an SD card, but can also be broadcast wirelessly via ESP-NOW to a receiver that can in turn send it over serial USB, or do whatever else one wishes. There’s also a neat feature that fires up a temporary WiFi access point on demand so log files can be downloaded with a web browser, no need to hook up a cable.

So far, so cool. But there’s still another nifty feature. [Update: originally the project had a link to the sim racing companion application Crew Chief. The developer clarified that at this writing, Open RC Spotter only supports its own Open RC Crew Chief application and not the similarly-named Windows sim racing assistant.] Open RC Spotter supports the Crew Chief telemetry protocol. Crew Chief is a piece of free Windows software that serves as a companion application for sim racing. It acts as a virtual race crew member, providing spoken information based on live telemetry read from supported racing sims.

Since Open RC Spotter supports the same telemetry format, one can use the virtual race engineer with RC car racing by simply feeding Open RC Spotter‘s serial data to the Crew Chief application. The RC telemetry data isn’t as rich as what comes from the racing sim APIs, but it’s more than enough to be useful.

People come up with all kinds of neat ideas when it comes to RC racing, and most of them depend on having access to good data. For example, a load cell in the steering mechanism can provides the data for force-feedback steering. We’ve even seen LiDAR and a depth camera used to automatically compute optimal racing lines.

A man standing next to an RC model of an Airbus A380 aircraft. The fuselage is at elbow height and the tailfin appears to be over his head.

World’s Biggest RC A380 Is A Big Deal

June 27, 2026 by 4 Comments

RC planes are a lot of fun, and the bigger the better! [Ramy RC] has built the world’s biggest RC A380.

At 29 ft (8.83 m) long, with a 32 foot (9.75 m) wingspan, and weighing 800 lb (362 kg), this 1/8 scale jumbo jet is not your typical model. The fuselage is built from CNC cut EPS foam layed up with fiberglass on the outside and carbon fiber inside. The wings have a combination of carbon, aluminum, foam, and wood components to handle the aerodynamic loads.

The attention to detail is wild. Instead of painting the windows, each one is an actual hole in the plane with a 3D printed window frame and acrylic window. You can actually see one falling out of the plane in the video below. An Airbus mechanic in the comments even notes the landing gear door order of operations are identical to the real thing.

If [Ramy] looks familiar, perhaps you remember his previous A380 build? Much like the 747, the full size A380 is no longer in production, but they can run on cooking oil while they’re still flying.

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