Well, you already know how things like this go. It started with adding the motor, which ended up being relatively straightforward once [Ben] used some community LEGO CAD tools to figure out which kits had the specific parts he needed to redesign the train in such a way that he’d have enough space inside for the motor without ruining the way it looked. But then the feature creep kicked in, and he found himself falling down that familiar rabbit hole.
The first problem was how to reliably power the train. It turns out the rear car was more or less empty already, so that became home for two 18650 batteries (the project details say “16850” but we believe that is merely a typo). [Ben] didn’t want to have to take the thing apart every time it ran down, so he wondered if it would be possible to add wireless charging.
A Qi coil in the bottom of the train car and one in a specially designed section of track got the power flowing, but getting them lined up proved a bit finicky. So he added a Hall effect sensor to the car and a strong magnet to the track, so the train would know when the coils were lined up and automatically pump the brakes.
So now he had a motorized train that could recharge itself, but how should he turn it on and off? Well, with an ESP8266 along for the ride, he figured it would be easy to add WiFi control. With a bit of code and the Homebridge project, he was able to get the train to appear as a smart switch to Apple’s HomeKit. That allows him to start and stop the train from his smartphone, complete with a routine that returns the train to the charging station once it’s finished making the rounds. [Ben] says the next steps are to put some sanity checks in, such as shutting the motors down if the train hasn’t passed the charging station in a few minutes; a sure sign that it’s not actually moving.
Electric bikes may be taking the world by storm, but the world itself doesn’t have a single way of regulating ebikes’ use on public roads. Whether or not your ebike is legal to ride on the street or sidewalk where you live depends mostly on… where you live. If you’re lucky enough to live in a place where a bicycle is legally defined as having fewer than four wheels and capable of being powered by a human, though, this interesting bike from Russia might be the best homemade ebike we’ve ever seen. (Video embedded below the break.)
While some of the details of this build might be lost on those of us who do not know any Slavic languages, the video itself shows off the features of this electric vehicle build quite well. It has a custom built frame with two wheels up front, each with its own independent suspension, allowing it to traverse extremely rough terrain with ease even a mountain bike might not be able to achieve. It seems to be powered by a relatively simple rear hub in the single rear wheel, and can probably achieve speeds in the 20 km/h range while holding one passenger and possibly some cargo.
The impressive part of this build isn’t so much the electrification, but rather the suspension components. Anyone looking for an offroad vehicle may be able to take a bit of inspiration from this build. If you’re more interested in the drivetrain, there are plenty of other vehicles that use unique electric drivetrains to check out like this electric boat. And, if you happen to know Russian and see some other interesting details in this build that the native English speakers around here may have missed, leave them in the comments for us.
We’ve been told that standing at a desk is good for you, but unless you’re some kind of highly advanced automaton you’re going to have to sit down eventually no matter what all those lifestyle magazines say. That’s where desks like the IKEA SKARSTA come in; they use a crank on the front to raise and lower the desk to whatever height your rapidly aging corporeal form is still capable of maintaining. All the health benefits of a standing desk, without that stinging sense of defeat when you later discover you hate it.
But who wants to turn a crank with their hand in 2019? Certainly not [iLLiac4], who’s spent the last few months working in conjunction with [Martin Mihálek] to add some very impressive features to IKEA’s adjustable table. Replacing the hand crank with a motorized system which can do the raising and lifting was only part of it, the project also includes a slick control panel with a digital display that shows the current table height and even allows the user to set and recall specific positions. The project is still in active development and has a few kinks to work out, but it looks exceptionally promising if you’re looking to get a very capable adjustable desk without breaking the bank.
The heart of the project is a 3D printable device which uses a low-RPM DC gear motor to turn the hex shaft where the crank would normally go. A rotary encoder is linked to the shaft of the motor by way of printed GT2 pulleys and a short length of belt, which gives the system positional information and avoids the complexity of adding limit switches to the table itself.
For controlling the motor the user is given the option between using relays or an H-Bridge PWM driver board, but in either event an Arduino Nano will be running the show. In addition to controlling the motor and reading the output of the rotary encoder, the Arduino also handles the front panel controls. This consists of a TM1637 four digit LED display originally intended for clocks, as well as six momentary contact tactile switches complete with 3D printed caps. The front panel’s simple user interface not only allows for setting and recalling three preset desk heights, but can even be used to perform the calibration routine without having to go in and hack the source code to change minimum and maximum positions.
Electric bikes are getting a lot of attention lately. Pretty much anyone can buy a kit online and get a perfectly street legal ride with plenty of range. But if you don’t want to take the kit route, and you’d rather take a tack that will get you noticed more around these parts, take some notes from [Jule553648]’s recent build that definitely isn’t using any parts from a kit.
The motor from the build is an electric power steering pump from a junkyard car. This gets mounted on a one-off rear bike rack and drives the rear tire with help from some gears from a pocket bike gearbox from eBay. A lot of the parts in this build were designed and built using CAD and a machine shop, and the parts for the battery and the power controller were sourced via China to save on cost.
The whole build has a homemade vibe that we find irresistible. The bike can go 35 km/h on level ground without breaking a sweat and has about 40 km of range which is nothing to scoff at. It might even be street legal depending on the wattage of the motor and whether or not you live in Europe (where throttles are generally not allowed on electric bikes). If you’re lacking a machine shop, though, we featured a very well-built kit ebike a while back that you could use as a model to get your feet wet.
No microcontroller, no display, and not even an LED in sight. That’s how [Made in Poland] decided to roll with this motorized linear plasma cutter, and despite the simplicity it really gets the job done when there’s metal to be cut.
Plasma cutting makes slicing and dicing heavy stock a quick job, but it’s easy to go off course with the torch or to vary the speed and end up with a poor edge. This tool takes the shakes out of the equation with a completely homebrew linear slide fabricated from square tubing. A carriage to hold the plasma cutter torch moves on a length of threaded rod chucked into the remains of an old cordless drill. The original clutch of the drill removes the need for limit switches when the carriage hits either end of the slide, which we thought was a great touch. Simple speed and direction controls are provided, as is a connection in parallel with the torch’s trigger. One nice feature of the carriage is the ability to swivel the torch at an angle, making V-groove welds in thick stock a snap. No need for a complicated bed with sacrificial supports and a water bath, either — just hang the stock over the edge of a table and let the sparks fall where they may.
Simple is better sometimes, but a CNC plasma table may still be your heart’s desire. We understand.
Artist Pe Lang uses linear polarization filters to create an unusual effect in his piece polarization | nº 1. The piece consists of a large number of discs made from polarizing film that partially overlap each other at the edges. Motors turn these discs slowly, and in the process the overlapping portions go from clear to opaque black and back again.
The disc rotation speed may be low but the individual transitions occur quite abruptly. Seeing a large number of the individual discs transitioning in a chaotic pattern — but at a steady rate — is a strange visual effect. About 30 seconds into the video there is a close up, and you can see for yourself that the motors and discs are all moving at a constant rate. Even so, it’s hard to shake the feeling of that one is watching a time-lapse. See for yourself in the video, embedded below.
[Tim] needed very small, motorized joints for a robot. Unable to find anything to fit the bill, he designed his own tiny, robotic joints. Not only are these articulated and motorized, they are designed to be independent – each containing their own driver and microcontroller.
None of the photos or video really give a good sense of just how small [Tim]’s design is. The motor (purple in the 3D render above, and pictured to the left) is a sub-micro planetary geared motor with a D shaped shaft. It is 6mm in diameter and 19mm long. One of these motors is almost entirely encapsulated within the screw it drives (green), forming a type of worm gear. As the motor turns the screw, a threaded ring moves up or down – which in turn moves the articulated shaft attached to the joint. A video is embedded below that shows the joint in action.
[Tim] originally tried 3D printing the pieces on his Lulzbot but it wasn’t up to the task. He’s currently using a Form 2 with white resin, which is able to make the tiny pieces just the way he needs them.