Author: Jenny List

3247 Articles

500cc Of 4-Wheel Off-Road Fun

August 9, 2024 by 8 Comments

Who among us hasn’t at some point thought of building a little vehicle, and better still, a little off-road vehicle for a few high-octane rough-terrain adventures. [Made in Poland] has, and there he is in a new video with a little off-road buggy.

The video which we’ve paced below the break is quite long, and it’s one of those restful metalworking films in which we see the finished project take shape bit by bit. In this case the buggy has a tubular spaceframe, with front suspension taken from a scrap quad and a home-made solid rear axle. For power there’s a 500cc Suzuki two-cylinder motorcycle engine, with a very short chain drive from its gearbox to that axle. The controls are conventional up to a point, though we’d have probably gone for motorcycle style handlebars with a foot shift rather than the hand-grip shift.

The final machine is a pocket drift monster, and one we’d certainly like to have a play with. We’d prefer some roll-over protection and we wonder whether the handling might be improved were the engine sprung rather than being part of a huge swing-arm, but it doesn’t appear to interfere with the fun. If you fancy a go yourself it’s surprisingly affordable to make a small vehicle, just build a Hacky Racer.

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An ESP Makes A Bicycle Odometer

August 7, 2024 by 4 Comments

If you’d like to measure the speed of your cycling then it’s easy enough to buy a cycle computer, but as [Clovis Fritzen] has done it’s also an option to build one. The result of his work is a smart PCB on which the speed is indicated with a row of LEDs.

The sensor is a straightforward affair, a reed switch with a magnet on a wheel, which is sensed by an ESP8266. The six LEDs are charlieplexeed over three lines. To keep the supply voltage correct for the ESP from the uncertain state of a lithium battery, a small buck-boost module is used. Sadly the code doesn’t seem to make the speed available via the wireless part of the processor, but we’re guessing that a bit of extra software work could fix that.

The result when put in a box on the handlebars, is a smart but simple instrument that would aid any bike. It’s by no means the first one we’ve brought you and we doubt it will be the last.

The 555 As A MOSFET Driver

August 5, 2024 by 26 Comments

To drive a MOSFET requires more than merely a logic level output, there’s a requirement to charge the device’s gate which necessitates a suitable buffer amplifier. A variety of different approaches can be taken, from a bunch of logic buffers in parallel to a specialised MOSFET driver, but [Mr. T’s Design Graveyard] is here with a surprising alternative. As it turns out, the ever-useful 555 timer chip does the job admirably.

It’s a simple enough circuit, the threshold pin is pulled high so the output goes high, and the PWM drive from an Arduino is hooked up to the reset pin. A bipolar 555 can dump a surprising amount of current, so it’s perfectly happy with a MOSFET. We’re warned that the CMOS variants don’t have this current feature, and he admits that the 555 takes a bit of current itself, but if you have the need and a 555 is in your parts bin, why not!

This will of course come as little surprise to anyone who played with robots back in the day, as a 555 or particularly the 556 dual version made a pretty good and very cheap driver for small motors. If you’ve ever wondered how these classic hips work, we recently featured an in-depth look.

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Your ESP32 As A USB Bluetooth Dongle

August 4, 2024 by 9 Comments

Using Bluetooth on a desktop computer is now such a seamless process; it’s something built-in and just works. Behind that ubiquity is a protocol layer called HCI, or Host Controller Interface, a set of commands allowing a host computer to talk to a Bluetooth interface.  That interface doesn’t have to be special, and [Dakhnod] is here to show us that it can be done with an ESP32 microcontroller through its USB interface.

The linked repository doesn’t tell us which of the ESP32 variants it works with, but since not all of them have a USB peripheral we’re guessing one of the newer variety. It works with Linux computers, and we’re told it should work with Windows too if a HCI driver is present. We might ask ourselves why such a project is necessary given the ubiquity of Bluetooth interfaces, but for us it’s provided the impetus to read up on how it all works.

We can’t find anyone else in our archive who’s made a Bluetooth dongle in this way, but we’ve certainly seen sniffing of HCI commands to reverse engineer a speaker’s communications.

All The Air Ducting Parts You Could Ever Need

August 4, 2024 by 49 Comments

If you have ever planned an air duct or dust extraction system for your shop, you’ll know just how difficult it can be to accommodate all but the simplest of arrangements. Off the shelf systems are intended for use in home heating or other domestic systems, and offer little flexibility of choice. Of course you could 3D print an adapter or two, but [Fabian] has taken it to the next level with a comprehensive library of 3D-printable pipe system adapters and accessories. We’re not sure we’ve seen such a complete collection.

The pipes are mostly at 125 mm diameter, with the full array of elbows and joints, alongside adapters for fans and smaller pipes, and different splitter options. It becomes particularly interesting in the accessories department though, because he’s also made a set of smart addons, packing ESP32s for sensors, and even valves.

It sometimes shocks us to go into hackerspaces and see nothing in the way of extraction around tools that really need it. Airborne smoke and particulates are a proven hazard, and thus we like this project a lot. If you don’t have adequate ventilation or extraction on your bench, consider printing yourself a solution. Take a look at how one hackerspace did it.

The Atomic Gardener Of Eastbourne

August 1, 2024 by 7 Comments

Pity the video team at a large hacker camp, because they have a huge pile of interesting talks in the can but only the limited resources of volunteers to put them online. Thus we often see talks appearing from past camps, and such it is with one from Electromagnetic Field 2022. It’s from [Sarah Angliss], and as its subject it takes the extraordinary work of [Muriel Howorth], a mid-20th-century British proponent of irradiated seeds as a means to solve world hunger.

Today we are used to genetic modification in the context of plants, and while it remains a controversial subject, the science behind it is well known. In the period following the Second World War there was a different approach to improving crops by modifying their genetics: irradiating seeds in a scattergun approach to genetic modification, in the hope that among thousands of duds there might be a mutant with special properties.

To this came Muriel Howorth, at first charged with telling the story of atomic research for the general public. She took irradiated seeds from Oak Ridge in the USA, and turned them into a citizen science program, with an atomic gardening society who would test these seeds and hopefully, find the supercrops within. It’s a wonderfully eccentric tale that might otherwise be the plot of a Wallace and Gromit movie, and but for a few interested historians of popular science it might otherwise have slipped into obscurity. We’re sorry we didn’t catch this one live back when we attended the event.

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Spin Your Own Passive Cooling Fibres

July 31, 2024 by 4 Comments

When the temperature climbs, it’s an eternal problem: how to stay cool. An exciting field of materials science lies in radiative cooling materials, things which reflect so much incoming heat that they can cool down from their own radiation rather than heating up in the sun. It’s something [NightHawkInLight] has been working on over a series, and he’s dropped a very long video we’ve placed below. It’s ostensibly about spinning radiative cooling fibers, but in fact provides a huge quantity of background as well as a bonus explanation of cotton candy machines.

These materials achieve their reflectivity by creating a surface full of microscopic bubbles. It’s the same process that makes snow so white and reflective, and in this case it’s achieved by dissolving a polymer in a mixture of two solvents. The lower boiling point solvent evaporates first leaving the polymer full of microscopic bubbles of the higher boiling point solvent, and once these evaporate they leave behind the tiny voids. In the video he’s using PLA, and we see him experimenting with different solvents and lubricants to achieve the desired result. The cotton candy machine comes in trying to create fibers by melting solid samples, something which doesn’t work as well as it could so instead he draws them by hand with a small rake.

When he tests his mat of fibers in bright sunlight the effect is almost magical if we didn’t already know the mechanism, they cool down by a few degrees compared to ambient temperature and the surrounding control materials. This is a fascinating material, and we hope we’ll see more experimenters working with it. You won’t be surprised to hear we’ve featured his work before.

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