Comparing Those Ten Cent Microcontrollers

June 10, 2024 by Jenny List 64 Comments

If you follow the world of microcontrollers, then you’ll probably be familiar with the most recent crop of ten cent parts. They bring power and features previously the preserve of much more expensive chips into the super-budget arena, and they’re appearing in plenty of projects on these pages.

If you’re not familiar with them it can seem daunting to decide which one to use, so to help you [Zach of All Trades] is comparing two of the more common ones. The CH32V003 with a RISC-V core and the PY32F002 with an ARM Cortex M0+ core are both pretty similar on paper, but which should you use?

The video below gives a run-down of each part along with some demonstrations before making its conclusions. The ARM-based part isn’t as quick as the RISC-V one but has a slight edge on peripherals, while the support is where a potential winner emerges in the shape of the CH32. That should be the last word, but for that the PY32 has the distance advantage over its rival of ready availability.

So this look at two families of cheap microcontrollers reveals the pros and cons of each, but in reality it provides an introduction to two sets of powerful chips for pennies.

As we’ve observed before, there are more chips to be found in this market.

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Can A Toy Printer Be Made Great?

June 9, 2024 by Jenny List 19 Comments

Now that the bottom end of the 3D printer market has been largely cleared of those garbage “Prusa i3 clone” models which used to infest it a few years ago, a new breed of ultra-cheap printer has taken their place. EasyThreed make a range of very small printers pitched as toys, and while they’re no great shakes by the standards of most Hackaday readers, they do at least work out of the box. For their roughly $75 price tag they deliver what you’d expect, but can such a basic machine be improved with a few upgrades? [Made with Layers] has taken a look.

These printers have an all-plastic snap-together construction with a 10 cm by 10 cm bed and a set of small geared stepper motors driving their axes. He concentrates on stiffening the structure, upgrading those motors, and because he’s sponsored by a 3D printer electronics company, upgrading their controller.

The motors were replaced first with some NEMA 11 steppers, and then by some over-sized ones which maybe push the idea a little far. By moving the motors to a bracket he was able to free up their mountings to secure a 3D printed insert to stiffen the arms. Perhaps he’s pushing it a little for the video with the electronics upgrade, but we think there’s a happy medium with the smaller of the two motor upgrades and the stiffening.

So if you have an EasyThreed in your life it’s possible to upgrade it into something a little better, but it’s worth asking whether that $75 might be better spent in saving for a better machine in the first place. We’ve been curious about these tiny printers for a while though, and it’s interesting to have some more of our questions answered.

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A Wireless Monitor Without Breaking The Bank

June 9, 2024 by Jenny List 8 Comments

The quality of available video production equipment has increased hugely as digital video and then high-definition equipment have entered the market. But there are still some components which are expensive, one of which is a decent quality HD wireless monitor. Along comes [FuzzyLogic] with a solution, in the form of an external monitor for a laptop, driven by a wireless HDMI extender.

In one sense this project involves plugging in a series of components and simply using them for their intended purpose, however it’s more than that in that it involves some rather useful 3D printed parts to make a truly portable wireless monitor, as well as saving the rest of us the gamble of buying wireless HDMI extender without knowing whether it would deliver.

He initially tried an HDMI-to-USB dongle and a streaming Raspberry Pi, however the latency was far too high to be useful. The extender does have a small delay, but not so bad as to be unusable. The whole including the monitor can be powered from a large USB power bank, answering one of our questions. All the files can be downloaded from Printables should you wish to follow the same path, and meanwhile there’s a video with the details below the break.

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Gas-Tight FDM 3D Printing Is Within Your Grasp

June 8, 2024 by Jenny List 65 Comments

The widespread availability of inexpensive 3D printers has brought about a revolution in what can be easily made at home. However these creations aren’t perfect, particularly when it comes to the adhesion between their layers. Aside from structural failures along the layer lines there is also the question of those joins being permeable, limiting the possibility for waterproof or gas proof prints. It’s something [German Engineer] has tackled in a new video, in which he’s looking at the design and preparation of small propane tanks.

A blurry image of a red 3d-printed part exploding — This is the frame at which the 3D printed tank explodes

The attraction of propane as a fuel is that it liquefies easily on compression, so a propane cylinder or tank will be an equilibrium of liquid propane with pressurized gas above it, whose pressure depends on the ambient temperature. This means that any tank must be expected to have a working pressure somewhere between 150 and 200 PSI, with of course a design pressure far exceeding that for safety reasons.

Filling a 3D printed tank immediately results in the propane escaping, as he demonstrates by putting one of his prints under water. He solves this with a sealant, Diamant Dichtol, which is intended to polymerize in the gaps between layers and create a gas-tight tank. A range of three tanks of different thicknesses are treated this way, and while the 1 mm thick variety bursts, the thicker ones survive.

It’s clear that this technique successfully creates gas-tight prints, and we can see the attraction of a small and lightweight fuel tank. But we can’t help worrying slightly about the safety, for even when the material is a lightweight 3D print, high pressure equipment is not to be trifled with. Tanks do burst, and when that happens anyone unfortunate enough to be close by sustains nasty, even life-threatening injuries. Use the technique, but maybe don’t hit it with high pressures.

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Retrotechtacular: TVO

June 6, 2024 by Jenny List 19 Comments

Hardware hackers come from a variety of backgrounds, but among us there remains a significant number whose taste for making things was forged through growing up in a farm environment. If that’s you then like me it’s probable that you’ll melt a little at the sight of an older tractor, and remember pretending to drive one like it at pre-school age, and then proudly driving it for real a few years later before you were smart enough to realise you’d been given the tedious job of repeatedly traversing a field at a slow speed in the blazing sun. For me those machines were Ford Majors and 5000s, Nuffields, the ubiquitous red Fergusons, and usually relegated to yard duty by the 1970s, the small grey Ferguson TE20s that are in many ways the ancestor of all modern tractors.

The Black Art Of Mixing Your Own Fuel

There was something odd about some of those grey Fergies in the 1970s, they didn’t run on diesel like their newer bretheren, nor did they run on petrol or gasoline like the family Austin. Instead they ran on an unexpected mixture of petrol and heating oil, which as far as a youthful me could figure out, was something of a black art to get right. I’d had my first encounter with Tractor Vapour Oil, or TVO, a curious interlude in the history of agricultural engineering. It brings together an obscure product of the petrochemical industry, a moment when diesel engine technology hadn’t quite caught up with the on-farm requirement, and a governmental lust for a lower-tax tractor fuel that couldn’t be illicitly used in a car.

TVO is a fuel with a low octane rating, where the octane rating is the resistance to ignition through compression alone. In chemical terms octane rating a product of how many volatile aromatic hydrocarbons are in the fuel, and to illustrate it your petrol/gasoline has an octane rating in the high 90s, diesel fuel has one close to zero, and TVO has a figure in the 50s. In practice this was achieved at the refinery by taking paraffin, or kerosene for Americans, a heavier fraction than petrol/gasoline, and adding some of those aromatic hydrocarbons to it. The result was a fuel on which a standard car engine wouldn’t run, but which would run on a specially low-compression engine with a normal spark ignition. This made it the perfect tax exempt fuel for farmers because it could only be used in tractors equipped with these engines, and thus in the years after WW2 a significant proportion of those Fergies and other tractors were equipped to run on it. Continue reading “Retrotechtacular: TVO” →

Tarzan, Lost Since 1983, Swings Back Onto The Atari 2600

June 6, 2024 by Jenny List 12 Comments

Computer gaming history is littered with tales of fabled lost hardware and software. Some of them are very famous such as the E.T. cartridges buried in a desert landfill or the few prototype SNES/CD-ROM hybrid that Nintendo was developing with Sony before the introduction of the PlayStation, but others have faded somewhat into obscurity. Among these is Tarzan for the Atari 2600, a game which was never released due to the 1983 console crash, and which the [Video Game History Foundation] have a report on its rediscovery and preservation.

The game was to be published by Coleco for their ColecoVision console as well as the 2600. The ColecoVision version was released and was apparently even fairly well reviewed, but the Atari port was canceled and its very existence eventually faded into obscurity.

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The Pi Pico, An SDR Receiver Front End

June 5, 2024 by Jenny List 22 Comments

Making a software defined radio (SDR) receiver is a relatively straightforward process, given the right radio front end electronics and analogue-to-digital converters. Two separate data streams are generated using clocks at a 90 degree phase shift, and these are passed to the software signal processing for demodulation. But what happens if you lack a pair of radio front ends and a suitable clock generator? Along comes [Mordae] with an SDR using only the hardware on a Raspberry Pi Pico. The result is a fascinating piece of lateral thinking, extracting something from the hardware that it was never designed to do.

The onboard RP2040 ADC is of course far too slow for the task, so instead an input is used, with a negative feedback arrangement from another GPIO to form a crude 1-bit ADC. A PIO peripheral is then used to perform the quadrature mixing, resulting in the requisite pair of data streams. At this point these are sent over USB to GNU Radio for demodulating, mainly for convenience rather than necessarily because the microcontroller lacks the power.

The result is a working SDR front end, demonstrated pulling in an FM broadcast station. The Pico has to be overclocked to reach that frequency and it’s more than a little noisy, but we’re extremely impressed with how much has been done with so little. Oddly it isn’t the first Pico SDR we’ve seen, but the previous one was a much more conventional and lower-frequency affair for the European Long Wave band.