I’ve Been Printing On The Dragon Railroad…

January 25, 2023 by Al Williams 28 Comments

We know many people who put much effort into building model train setups. But [Rambros] has an entire set 3D printed, and the files are open source, so you can print your own or modify it to suit you. When we first read “complete open source ecosystem,” we thought it might have been a bit of hyperbole, but it isn’t. The S-scale set includes two locomotives, a tanker, a box car, a hopper car, and a gondola car. There are different sections of track, customizable with Fusion 360. The “Dragon Railway” takes a few mechanical parts and electronics, of course. You can see one of several videos about the system below.

You can control the whole system using Bluetooth and a smartphone. The electronics are pretty simple, consisting of an ESP32 board, some motor drivers, N20 motors, and a few miscellaneous parts. We expect it would be compatible with other off-the-shelf S scale tracks and cars, but we don’t know that for sure.

Although you’ll need Fusion 360 to customize, there are plenty of ready-made STL files if you want to get started quickly. Some of the track items, like the crossing and turnout are not customizable, anyway. One particularly impressive item is a printed auto-coupler; while a small item, getting that to work reliably with printed parts seems like it may be the most difficult part of the whole thing.

Maybe an OLED display would be the next thing? We’ve seen other printed trains, but this seems like a real labor of love.

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RC Car Gets F1-Style DRS Rear Wing

January 21, 2023 by Lewin Day 1 Comment

DRS, or the Drag Reduction System, has become a key part of Formula 1 in the past decade. [Engineering After Hours] decided to implement the same system on an RC car instead.

The DRS system was implemented in Formula 1 to increase passing in the series. By moving a flap in the rear wing of the race cars, drag could be reduced, allowing a car to attain a higher top speed on the straights. The racing series limited the activation of the DRS wing to only cars following closely behind another. This artificially enabled them to gain a speed boost over the car in front to aid passing.

[Engineering After Hours] wanted to see if a tiny wing on a small RC car could work the same way. It would fundamentally come down to whether moving a tiny wing element would appreciably change the car’s drag or not. Naturally, on such a small scale, attaining high speeds would be necessary to detect much difference. At lower speeds, the difference in drag would likely be too negligible to notice.

The RC-scale DRS system fundamentally does work. With DRS engaged, flattening out the rear wing elements noticably reduced downforce at the rear. With the DRS not engaged, though, the rear wing on the car was creating so much downforce that the car was squatting at the rear and occasionally flipping end over end. [Engineering After Hours] didn’t get any top speed measurements, but estimated that the wing could potentially increase top speed by up to 7 mph with the DRS enabled.

We’ve seen [Engineering After Hours] bring other fun motorsport tech to RC cars before, too, like this amazing fan car build.

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CUTTING CABLES CURES TANGLED CORD CHAOS

January 10, 2023 by Anool Mahidharia 11 Comments

The Toniebox is a toy that plays stories and songs for kids to listen to. Audio content can be changed by placing different NFC enabled characters that magnetically attach to the top of the toy. It can play audio via its built-in speaker or through a wired headphone connected to the 3.5 mm stereo jack. Using the built in speaker could sometimes be quite an irritant, especially if the parents are in “work from home” mode. And wired headphones are not a robust alternative, specially if the kid likes to wander around or dance while listening to the toy. We guess the manufacturers didn’t get the memo that toddlers and cables don’t mix well together. Surprisingly, the toy does not support Bluetooth output, so [g3gg0] hacked his kids Toniebox to add Bluetooth audio output.

[g3gg0] first played with the idea of transmitting audio via an ESP32 connected to the I²S interface, running a readily available A2DP library. While elegant, it is a slightly complex and time consuming solution. Using the ESP32 would also have affected the battery life, given the ESP32’s power hungry nature. Continue reading “CUTTING CABLES CURES TANGLED CORD CHAOS” →

A Christmas-themed LEGO train engine and coal car

ESPHome Powers Festive Lego Train Set

December 27, 2022 by Robin Kearey 5 Comments

While the basic concept of LEGO bricks might have changed little since the mid-20th century, some components such as motors and sensors are still affected by technological progress and end up obsolete and unsupported. [Travis] ran into this problem when he was building a festive train setup and realized he didn’t have the speed controller to match his train engine. Without that part, the engine would only run at full speed and derail as soon as it hit a curve. The official speed controller had been discontinued and was hard to find, so [Travis] had to resort to building his own.

The basic components needed were an H-bridge driver to operate the motor and an ESP8266 to generate PWM signals. In order to keep the bricky appearance of the train engine intact, [Travis] hollowed out a few cheap imitation LEGO bricks to house the electronics. He also cut out slots for JST connectors, which are far more convenient to work with than LEGO’s brick-style connectors.

The ESP8266 runs ESPHome, which enables [Travis] to control the entire setup using Home Assistant. The train is programmed to run a few laps at the top of the hour and play choo-choo sounds from a mini MP3 player hidden in the coal car. That car also holds a standard AA battery holder to power the system, which makes it easy to swap the batteries without having to partially disassemble the train.

There are various ways to control LEGO creations using standard computer platforms: we’ve seen the ESP32 powering a LEGO tank, for instance. If you need a bit more computing power, there’s even an official LEGO Raspberry Pi HAT.

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A Concealed Model Railway Rises To The Occasion

December 13, 2022 by Jenny List 5 Comments

Occasional pieces of furniture serve little purpose other than to fill a space and maybe display a prized ornament or two. Who hasn’t got a relative with one two many small tables or display stands overfilling the available space!

If you visit [Peter Waldraff]’s house though, those pieces of furniture may not be what they seem. His display pedestal for example hides an N gauge railway layout that rises from the depths on a system of pulleys, with the action triggered by moving the vase displayed on its top. The vase conceals a magnet, which operates a reed switch that in turn controls the winch motor.

The layout is a loosely Batman themed train chase, with concentric spirals of track forming a continuous loop on which two trains run. There’s an ingenious arrangement with a reed switch and a piece of dead track to ensure that the chasing train is always held to ensure a gap between them. The landscaping is of a set of cliffs with a model of Wayne manor at the top, and there’s even a LED-lit Batmobile. One of the locomotives is recognisably based on a character from the Thomas the Tank Engine books.

All in all we like the ingenuity of this layout, but if you like it too then we’ve got a treat for you. Sharp-eyed readers will remember that this isn’t the first such project from Peter.

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A Simon toy with a robot that slaps little hands against it

Silicone-Slapping Servos Solve Simon Says

December 6, 2022 by Robin Kearey 7 Comments

Most modern computer games have a clearly-defined end, but many classics like Pac-man and Duck Hunt can go on indefinitely, limited only by technical constraints such as memory size. One would think that the classic electronic memory game Simon should fall into that category too, but with most humans struggling even to reach level 20 it’s hard to be sure. [Michael Schubart] was determined to find out if there was in fact an end to the latest incarnation of Simon and built a robot to help him in his quest.

The Simon Air, as the newest version is known, uses motion sensors to detect hand movements, enabling no-touch gameplay. [Michael] therefore made a system with servo-actuated silicone hands that slap the motion sensors. The tone sequence generated by the game is detected by light-dependent resistors that sense which of the segments lights up; a Raspberry Pi keeps track of the sequence and replays it by driving the servos.

We won’t spoil the ending, but [Michael] did find an answer to his question. An earlier version of the game was already examined with the help of an Arduino, although it apparently wasn’t fast enough to drive the game to its limits. If you think Simon can be improved you can always roll your own, whether from scratch or by hacking an existing toy.

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3d printed escalator, from side, showing mechanism

Tiny 3D Printed HO Scale Escalator That Works

November 29, 2022 by Anne Ogborn 25 Comments

[Luke Towan] has a cool HO scale Escalator mostly made of 3D printed parts, with some laser cut acrylic, for a station on his HO model railroad.

Escalators are mesmerizing to watch – there’s something magical about the stairs unfolding at the bottom and folding up at the top. But they’re very hard to model.

[Luke Towan] has done it – his 3D printed version closely resembles the real thing mechanically. Pins are carried around, cantilevered out from a 3D printed chain. A stair swivels on each pin – at the bottom each stair’s free end rests on a ‘bottom’ far enough down for the stairs to be level, while on the incline the ‘bottom’ is just below the pins. It’s a tricky build.

If you like pushing the envelope of what 3D printing can do this is an interesting project, even if you’re not planning to build an escalator. There are lots of tips for making small mechanisms with 3D printing, and for making small mechanisms that work reliably without stuttering.

He’s not the first to build an escalator. Back in 2015 we covered this wooden escalator for slinkies, and just recently this 3D printed version from [AlexY].