STM32 Oscilloscope Uses All The Features

August 8, 2023 by Bryan Cockfield 29 Comments

[jgpeiro] is no slouch when it comes to building small, affordable oscilloscopes out of common microcontrollers. His most recent, based on an RP2040 with two channels that ran at 100 MSps, put it on the order of plenty of commercially-available oscilloscopes at this sample rate but at a fraction of the price. He wanted to improve on the design though, making a smaller unit with a greatly reduced bill-of-materials and with a more streamlined design, so he came up with this STM32-based oscilloscope.

The goal of this project was to base as many of the functions around the built-in capabilities of the STM32 as possible, so in addition to the four input channels and two output channels running at 1 MHz, the microcontroller also drives a TFT display which has been limited to 20 frames per second to save processor power for other tasks. The microcontroller also has a number of built-in operational amplifiers which are used as programmable gain amplifiers, further reducing the amount of support circuitry needed on the PCB while at the same time greatly improving the scope’s capabilities.

In fact, the only parts of consequence outside of the STM32, the power supply, and the screen are the inclusion of two operational amplifiers included to protect the input channels from overvoltage events. It’s an impressive build in a small form factor, and we’d say the design goal of keeping the parts count low has been met as well. If you do need something a little faster though, his RP2040-based oscilloscope is definitely worth checking out.

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No Need To Buy A Woodchipper – Build One!

August 8, 2023 by Dave Rowntree 32 Comments

Polish YouTuber WorkshopFromScratch finally got fed up with tripping over piles of garden detritus and decided to have a go at building a woodchipper (Video, embedded below). Since they had a ‘small’ 1.5kW gearmotor just lying idle (as you do) it was an obvious fit for a machine that needs torque rather than supersonic speed. The video is a fabulous 20-minute journey through the workshop showing just about every conceivable metalworking tool being used at some point.

Checkout out the thickness of my blades!

One interesting point is the bottom roller, which sits between a pair of removable guides, which should help the thing self-feed without jamming. Whether that was necessary is not for us to judge, but it can’t hurt. The frame looks like it was constructed from at least 1/4″ thick steel, which is expensive if you don’t happen to have a supply to hand. There’s lots to see, everything from thin sheet metalworking, which was plasma cut, constructing the feed and exhaust guides, to box sections being skilfully welded at some interesting angles to make a cart to move the thing. They tell us the blades were constructed from some seriously thick slabs of C45 grade steel, but currently are not hardened. This is planned for the future, but we suspect not something that is easily achieved in the home workshop!

If this channel is familiar, then you might remember the earlier stump grinder they built. If you are drowning in sawdust, but have a log burner, then you’ll appreciate this sawdust briquette machine.

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Hackaday Prize 2023: Machining Metals With Sparks

August 8, 2023 by Bryan Cockfield 3 Comments

Working with metals can present a lot of unique challenges even for those with a fairly well-equipped shop. Metals like aluminum and some types of steel can be cut readily with grinders and saws, but for thick materials or some hardened steels, or when more complex cuts need to be made, mechanical cutting needs to be reconsidered in favor of something electric like electrical discharge machining (EDM) or a plasma cutter. [Norbert] has been on the path of building his own EDM machine and walks us through the process of generating a spark and its effects on some test materials.

Armed with a microscope, a homemade high-voltage generator, drill bit, and a razor blade to act as the workpiece, [Norbert] begins by experimenting with electrical discharges by bringing the energized drill bit close to the razor to determine the distance needed for effective electrical machining. Eventually the voltage is turned up a bit to dive into the effects of higher voltage discharges on the workpiece. He also develops a flushing system using de-ionized water, and then finally a system to automate the discharges and the movement of the tool.

While not a complete system yet, the videos [Norbert] has created so far show a thorough investigation of this metalworking method as well as some of the tricks for getting a setup like this working. EDM can be a challenging method for cutting metal as we’ve seen before with this similar machine which uses wire as the cutting tool, but some other builds we’ve seen with more robust electrodes have shown some more promise.

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Prepare To Brake: Quick Intro To Metal Bending

August 5, 2023 by Al Williams 9 Comments

If you want to bend metal to make shapes, you might use equipment like a brake. But if you don’t have one, no worries. You can still do a lot with common tools like a vise and torches. [Bwrussell] shows you how. He welds together a die to use as a bending jig and makes a set of table legs.

You might think that putting metal in a vise and bending it isn’t exactly brain surgery. It isn’t, but there is more to it than that. Starting with a bending plan and the creation of the jigs, clamping and bending is only part of it. You can see a little bit of the action in the video below.

Speaking of planning, the design was in Fusion 360’s sheet metal workflow. To facilitate the bends, the build uses two torches. A MAPP torch gets very hot, and a propane torch makes sure that a larger area stays hot. There are quite a few tips you can pick up in this post, even if you aren’t making table legs.

Fusion 360 does a lot of the design work, but if you want a quick lesson on what happens when you bend metal, we can help. Want to make your own metal brake?

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Repairing A Home Injection Molding Machine

August 5, 2023 by Maya Posch 10 Comments

When [Michael] over at the Teaching Tech YouTube channel bought a hobby injection molding machine a long time ago, one of the plans he had with it was to use it for grinding up waste bits of PLA filament for injection molding. Since the machine was bought from a US shop and [Michael] is based in Australia it required some modifications to adapt it to the local 220+ VAC mains, followed by adding a PID temperature controller and a small compressor to provide the compressed air rather than from a large shop compressor.

Although [Michael] had discussed using the machine for PLA with the seller to confirm that this would work, a user error meant that the now defective unit had been sitting idly for many years, until recently.

Since the machine had been gathering dust and rust in the garage, fixing the machine up took a complete teardown to remove corrosion and resolve other issues. After this the original fault was identified, which turned out to be a shorted wire near the heater which had been turned up to a too high temperature, leading to the release of magic smoke and banishment of the machine to the Pit of Despair, AKA the shadowy depths of one’s garage.

In this first installment, [Michael] cleaned up the machine and restored it to a working state. In the next part injection molding will be attempted again, which should give some idea of the feasibility of turning scraps of PLA and failed 3D prints into smooth injection molded parts, assuming you have the CNC machine or patience to carve out the requisite molds, of course.

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The Simplest Curve Tracer Ever

August 2, 2023 by Dan Maloney 15 Comments

To a lot of us, curve tracing seems to be one of those black magic things that only the true wizards understand. But as [DiodeGoneWild] explains, curve tracing really isn’t all that complicated, and it doesn’t even require specialized test instruments — just a transformer, a couple of resistors, and pretty much whatever oscilloscope you can lay your hands on.

True to his handle, [DiodeGoneWild] concentrates on the current-voltage curves of Zener diodes in the video below, mainly as a follow-up to his recent simple linear power supply project, where he took a careful look at thermal drift to select the best Zener for the job. His curve tracer is super simple — just the device under test in series with a bunch of 10-ohm resistors and the secondary winding of a 12-volt transformer. The probes of his oscilloscope — a no-frills analog model — go across the DUT and the resistor, and with the scope in X-Y mode, the familiar current-voltage curve appears. Sure, the trace is reversed, but it still provides a good visualization of what’s going on. The technique also works on digital scopes; just be ready for a lot of twiddling to get into X-Y mode and to get the trace aligned.

Of course it’s not just diodes that can be tested with a curve tracer, and [DiodeGoneWild] showed a bunch of other two-lead components on his setup. But for our money, the neatest trick here was using a shorted bridge rectifier to generate a bright spot on the curve to mark the zero crossing point. Clever indeed, and pretty useful on a scope with no graticule.

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Open-Source Firmware For Soldering Irons

August 2, 2023 by Bryan Cockfield 23 Comments

For most of us, the first soldering iron we pick up to start working on electronics has essentially no features at all. Being little more than resistive heaters plugged straight into the wall with perhaps a changeable tip, there’s not really even a need for a power switch. But doing anything more specialized than through-hole PCB construction often requires a soldering iron with a little more finesse, though. Plenty of “smart” soldering irons are available for specialized soldering needs now, and some are supported by the open-source IronOS as well.

The project, formerly known as TS100, is a versatile soldering iron control firmware that started as an alternative firmware for only the TS100 soldering iron. It has since expanded to have compatibility with several other soldering irons and hosts a rich set of features, including temperature control, motion activation, and the ability to temporarily increase the temperature when using the iron. The firmware is also capable of working with irons that use batteries as well as irons that use USB power delivery.

For anyone with a modern smart soldering iron, like the Pinecil or various Miniware iron offerings, this firmware is a great way of being able to gain fine control over the behavior of one’s own soldering iron, potentially above and beyond what the OEM firmware can do. If you’re still using nothing more than a 30W soldering iron that just has a wall plug, take a look at a review we did for the TS100 iron a few years ago to see what you’re missing out on.

Photo via Wikimedia Commons