Mysterious Files PH

At first glance, wireless brakes seem like a recipe for disaster. For something as critical as braking, many bicyclists might prefer a physical connection to their method of safely controlling speed. But there are a number of surprising benefits of electronic or wireless braking systems. For one, they can enable systems like anti-lock braking systems and for another they can eliminate cabling or hydraulics on a bicycle. For these reasons, and just for the thrill of it, [Berm Peak] built a set of wireless brakes for his fat tire bicycle to test out the possibilities.

The system uses a set of ESP32 microcontrollers to handle inputs from the braking lever and outputs to the front and rear brakes, as well as a central control unit and display. The brakes themselves are controlled by actuators from car door locks, which when combined with the springs from the stock calipers work to apply a wide range of braking force to the wheels. These did take a bit of prototyping to get working right, by changing to higher quality calipers, increasing the angle of the actuator, and adding longer levers, but eventually a working braking system started to appear.

But replacing a hydraulic system with an electronic one isn’t where something like this shines. [Berm Peak] was able to add in a number of features impossible in traditional braking systems. Not only does this have an ABS system and the possibility to remotely slow down his children’s bikes when they’re riding, but there’s also a braking equalizer that allows the rider to control how much braking there is at certain positions of the brake lever, and another setting called “derp” which doesn’t engage the brakes at all until a certain threshold has passed. This might end up being the next big trend in mountain biking, unlike airless tires.

Needing less than 70 grams of filament, [Chefkoch]’s 3D printed PCB vise solder station might be a good way to use up some filament spool leftovers and get yourself a handy tool in return.

What we like about this design is that it is multi-functional, and cleverly uses the solder spool as a counterweight to add stability that might otherwise be lacking in such a compact design.

The assembly can be reconfigured so that the jaws are either horizontal or vertical; the solder spool is held conveniently either way. The whole thing is 3D printed, so there’s no other hardware or fasteners involved. It’s probably best suited to small boards, but it’s also compact, entirely 3D printed, and doesn’t need much filament.

Still have some filament left over and want a nifty solder feeder to go with it? Check out the solder scroll, a pen-like DIY tool that makes handheld solder feeding a little less of a hassle.

The Cheap Yellow Display (CYD) is a board carrying a slightly older ESP32 variant, a display with a resistive touchscreen, an SD card, and not much else. It’s often used for straightforward microcontroller applications that need a user interface, but that’s not the limit of its possibilities. [Alun Morris] has a CYD on which you can brows an entire offline Wikipedia.

The trick is to take the offline Wikipedia builds from the Kiwix project, and process them further into a custom format suited for a browser firmware on the ESP32. A modern SD card can hold so much data that a full Wikipedia is well within its abilities even with images included.

We like this idea, because it takes the knowledge away from the center of the network to its edge. We expect to see it gaining a following among enthusiasts for offline living, because all that knowledge without a network can only be useful. If you recognize [Alun]’s work, it might be because of his ESP32 web browser.

Having access to a planer opens up a lot of options for woodworking. It enables a craftsman to work with much rougher lumber and the finished results generally have tighter tolerances. But as [DendroLabsDev] found out, the height adjustment wheel on a planer needs a lot of turns to go from its lowest to highest position, and this gets tiresome when greasing parts during maintenance. So what started as a quick hack to quickly perform this single maintenance task eventually resulted in this programmable height adjustment that’s in use on the planer full-time now.

The motor attached to the height adjustment for the planer is a stepper motor, capable of around 1000 steps per inch. Since revolutions on this tool with the stock wheel adjust only a small amount per revolution, this can in theory enable very small tolerances to be dialed in consistently. Not only that, but [DendroLabsDev] has programmed it with a few different modes, the first of which allows a board to be planed to a certain thickness by making several passes, mimicking the workflow of a human-controlled machine. Then a device to zero the position was added, and then the ability to save the height adjustments to make replication across different boards was added, and then a mode to step through set amounts per pass.

What [DendroLabsDev] has essentially made is a high-dollar planer control that is actually available in the most expensive planers, but adapted for a DeWalt planer easily available and semi-affordable at many local hardware stores. It is also theoretically adaptable for any planer with an adjustment wheel, and [DendroLabsDev] has some plans to improve the control system and package it with a PCB and enclosure that would allow it to be a more accessible product for other woodworkers. Adding electronics to woodworking tools other than routers is a popular pastime, take this CNC-controlled scroll saw for example.

It’s technically true that any piece of software can be reproduced in hardware, although modern software’s size and complexity generally makes this a non-starter. But if we go far enough back in time, older software becomes easier and easier to implement in hardware. The original DOOM from 1993 might one day be recreated in full this way, but that day is not today. Instead, [Nick] has recreated the original music from that game, playing the opening track in nothing but 555 timers.

The circuit starts with a 555 timer that acts as a system clock with a rate of just over 7 Hz. These pulses feed a binary counter which in turn feeds a decoder, giving the circuit 15 positions. Each output of the decoder feeds to a diode matrix which stores information about what pitch the circuit should play. The circuit only needs to play six pitches so the diodes effectively connect each moment in time to one of these six notes. From there the circuit feeds into a set of switches which select different resistor networks of another 555 which is actually responsible for producing sound. The resistor networks have different values to adjust the timing of the 555 to produce different pitches.

Of course this entire exercise is largely academic as almost any microcontroller would be able to be programmed to play this chiptune quite easily, but it’s not a bad idea to get down into the weeds of digital logic from time to time in order to refine one’s skills and knowledge about what’s really going on in the inner workings of circuits. Or, go even deeper than that and build the logic gates themselves from first principles.

After building a couple of internal combustion engines by milling billet aluminium stock and cringing at the absolute waste of material this created, [Camden Bowen] figured he’d give casting metal parts a shot. Of course, the key here is to create the molds for said casting, which is where you got a few options available.

Since DIY is really his thing, he also made his own kiln using cement and perlite, plus a propane burner. For the aluminium material to melt, he bought a stack of aluminium alloy wheels, as these are made of an alloy that’s actually suitable for casting. These were turned into ingots as a first step towards casting the engine parts, which among other things helps to purify the metal.

For the actual casting method he picked lost PLA, meaning the intended shape is 3D printed in PLA, then put into plaster before it’s melted out of the newly minted mold in an oven and subsequently burned out in the kiln. For the plaster [Camden] used regular Plaster of Paris, mixed with sand to give it suitable heat-resistant properties.

After some trial and error, as well as a lot of trouble burning out all the PLA, he got a usable mold and managed to eventually cast an engine cylinder with only a few imperfections. Considering just how convoluted it would have been to mill that part out of billet aluminium, it’s easy to see why commercial manufacturers are casting such parts as well.

[Artificial-Age] has built a rather unique way to play old Game Boy games. It’s an emulator, but it doesn’t work in quite the way you might think!

Since the Game Boy is a relatively simple 8-bit machine that runs at a leisurely 4 MHz or so, it is well within the capabilities of an ESP32 microcontroller to emulate. [Artificial-Age] got an ESP32-S3 and programmed it to do just that. However, there’s a twist—there is no screen hooked up to the microcontroller, nor any buttons. Instead, the board is accessed over a WiFi access point that it hosts itself.

One then opens a web browser, which streams the emulated video and audio from the console, while accepting button inputs from your keyboard or touchscreen, depending on the platform you’re viewing the web interface on. ROMs are stored on the ESP32’s flash storage, and can be uploaded via the web interface.

It’s an interesting setup, and one that perhaps doesn’t make obvious sense at first. After all, any modern smartphone can easily emulate a Game Boy, too. However, this setup makes it easy to share the emulator with other people, who can simply check out the WiFi AP and web interface without having to download or or install anything on their own device. We’ve featured some other fun emulation projects lately, too.