Test Pattern Generator For SCART And RGB TVs

September 19, 2025 by Tyler August 3 Comments

CRTs don’t last forever, and neither do the electronics that drive them. When you have a screen starting to go wonky, then you need a way to troubleshoot which is at fault. A great tool for that is a pattern generator, but they’re not the easiest to come by these days. [baritonomarchetto] needed a pattern generator to help repair his favourite arcade machine, and decided to make his own DIY Portable RGB CRT Test Pattern Generator.

One of the test patterns available from the device. This TV appears to be in good working order.

While he does cite [Nicholas Murray]’s RP2040 test pattern generator as a starting point (which itself builds on the PicoVGA library once featured here), he couldn’t just build one. That worthy project only outputs VGA and because [baritonomarchetto] is in Europe, he needed a SCART connector. Since he’s working on arcade machines, he needed non-SCART RGB signals, too. The arcade signals need to be at higher voltages (TLL level) than the RGB signal you’d find in SCART and VGA.

The upshot is while he’s using [Nicholas]’s code for the RP2040, he’s rolled his own PCB, including a different resistor ladders to provide the correct voltages depending on if he’s dealing with a home TV or arcade CRT. To make life easier, the whole thing runs off a 9V battery.

If you’re wondering what the point of these test patterns is, check out this 1981-vintage pattern generator for some context from the era. If a digital replica doesn’t float your boat, it is possible to recreate the original analog circuitry that generated these patterns back when the CRT was king.

Dirty Pots, Meet Power Tools!

September 19, 2025 by Tyler August 26 Comments

Let’s face it, nobody likes scrubbing, but what option do you have? You can’t exactly break out the grinder to clean off the remains of last nights dinner… right? Well, maybe not a grinder, but thanks to this hack by [Markus Opitz], you can use an oscillating tool.

It’s a simple enough hack: [Markus] modeled the attachment for his Bosch oscillating tool in Tinkercad, and created a bracket to hold a large metal binder clip. The clip attaches with a screw, and can hold whatever scrubbing pad your carpel-tunnel afflicted hands can’t bear to hold on to. He’s using a self-cleaning stainless-steel sponge.

One nice touch is a pair of protective lips on the jaws of the metal clip, to keep it from accidentally scratching the delicate surface under care. Of course if you have a drill or a Dremel handy you can buy attachments for polishing disks of various grits, but what’s the fun in that? Doing the dishes with a hacked-together oscillating tool just somehow seems more fun. Plus this way you can’t accidentally produce an engine-turning pattern.

We don’t seem to have featured many hacks for these fun, buzzing, multi-purpose tools, so if you’ve got one send us a tip. We did feature an oscillating cutter for CNC once, but that was fully DIY.

Reverse-Engineering The Milwaukee M18 Diagnostics Protocol

September 14, 2025 by Maya Posch 19 Comments

As is regrettably typical in the cordless tool world, Milwaukee’s M18 batteries are highly proprietary. Consequently, this makes them a welcome target for reverse-engineering of their interfaces and protocols. Most recently the full diagnostic command set for M18 battery packs were reverse-engineered by [ToolScientist] and others, allowing anyone to check useful things like individual cell voltages and a range of statistics without having to crack open the battery case.

These results follow on our previous coverage back in 2023, when the basic interface and poorly checksummed protocol was being explored. At the time basic battery management system (BMS) information could be obtained this way, but now the range of known commands has been massively expanded. This mostly involved just brute-forcing responses from a gaggle of battery pack BMSes.

Interpreting the responses was the next challenge, with responses like cell voltage being deciphered so far, but serial number and the like being harder to determine. As explained in the video below, there are many gotchas that make analyzing these packs significantly harder, such as some reads only working properly if the battery is on a charger, or after an initial read.

Continue reading “Reverse-Engineering The Milwaukee M18 Diagnostics Protocol” →

A lathe is shown on a tabletop. Instead of a normal lathe workspace, there is an XY positioning platform in front of the chuck, with two toolposts mounted on the platform. Stepper motors are mounted on the platform to drive it. The lathe has no tailpiece.

Turning A Milling Machine Into A Lathe

September 13, 2025 by Aaron Beckendorf 8 Comments

If you’re planning to make a metalworking lathe out of a CNC milling machine, you probably don’t expect getting a position sensor to work to be your biggest challenge. Nevertheless, this was [Anthony Zhang]’s experience. Admittedly, the milling machine’s manufacturer sells a conversion kit, which greatly simplifies the more obviously difficult steps, but getting it to cut threads automatically took a few hacks.

The conversion started with a secondhand Taig MicroMill 2019DSL CNC mill, which was well-priced enough to be purchased specifically for conversion into a lathe. Taig’s conversion kit includes the spindle, tool posts, mounting hardware, and other necessary parts, and the modifications were simple enough to take only a few hours of disassembly and reassembly. The final lathe reuses the motors and control electronics from the CNC, and the milling motor drives the spindle through a set of pulleys. The Y-axis assembly isn’t used, but the X- and Z-axes hold the tool post in front of the spindle.

The biggest difficulty was in getting the spindle indexing sensor working, which was essential for cutting accurate threads. [Anthony] started with Taig’s sensor, but there was no guarantee that it would work with the mill’s motor controller, since it was designed for a lathe controller. Rather than plug it in and hope it worked, he ended up disassembling both the sensor and the controller to reverse-engineer the wiring.

He found that it was an inductive sensor which detected a steel insert in the spindle’s pulley, and that a slight modification to the controller would let the two work together. In the end, however, he decided against using it, since it would have taken up the controller’s entire I/O port. Instead, [Anthony] wired his own I/O connector, which interfaces with a commercial inductive sensor and the end-limit switches. A side benefit was that the new indexing sensor’s mounting didn’t block moving the pulley’s drive belt, as the original had.

The end result was a small, versatile CNC lathe with enough accuracy to cut useful threads with some care. If you aren’t lucky enough to get a Taig to convert, there are quite a few people who’ve built their own CNC lathes, ranging from relatively simple to the extremely advanced.

Looking in the back of the Tektronix 577

Repairing A Tektronix 577 Curve Tracer

September 4, 2025 by John Elliot V 5 Comments

Over on his YouTube channel our hacker [Jerry Walker] repairs a Tektronix 577 curve tracer.

A curve tracer is a piece of equipment which plots I-V (current vs voltage) curves, among other things. This old bit of Tektronix kit is rocking a CRT, which dates it. According to TekWiki the Tektronix 577 was introduced in 1972.

In this repair video [Jerry] goes to use his Tektronix 577 only to discover that it is nonfunctional. He begins his investigation by popping off the back cover and checking out the voltages across the voltage rails. His investigations suggest a short circuit. He pushes on that which means he has to remove the side panel to follow a lead into the guts of the machine.

Continue reading “Repairing A Tektronix 577 Curve Tracer” →

A camera-based microscope is on a stand, looking down towards a slide which is held on a plastic stage. The stage is held in place by three pairs of brass rods, which run to red plastic cranks mounted to three stepper motors. On the opposite side of each crank from the connecting rod is a semicircular array of magnets.

Designing An Open Source Micro-Manipulator

September 4, 2025 by Aaron Beckendorf 21 Comments

When you think about highly-precise actuators, stepper motors probably aren’t the first device that comes to mind. However, as [Diffraction Limited]’s sub-micron capable micro-manipulator shows, they can reach extremely fine precision when paired with external feedback.

The micro-manipulator is made of a mobile platform supported by three pairs of parallel linkages, each linkage actuated by a crank mounted on a stepper motor. Rather than attaching to the structure with the more common flexures, these linkages swivel on ball joints. To minimize the effects of friction, the linkage bars are very long compared to the balls, and the wide range of allowed angles lets the manipulator’s stage move 23 mm in each direction.

To have precision as well as range, the stepper motors needed closed-loop control, which a magnetic rotary encoder provides. The encoder can divide a single rotation of a magnet into 100,000 steps, but this wasn’t enough for [Diffraction Limited]; to increase its resolution, he attached an array of alternating-polarity magnets to the rotor and positioned the magnetic encoder near these. As the rotor turns, the encoder’s local magnetic field rotates rapidly, creating a kind of magnetic gear.

A Raspberry Pi Pico 2 and three motor drivers control this creation; even here, the attention to detail is impressive. The motor drivers couldn’t have internal charge pumps or clocked logic units, since these introduce tiny timing errors and motion jitter. The carrier circuit board is double-sided and uses through-hole components for ease of replication; in a nice touch, the lower silkscreen displays pin numbers.

To test the manipulator’s capabilities, [Diffraction Limited] used it to position a chip die under a microscope. To test its accuracy and repeatability, he traced the path a slicer generated for the first layer of a Benchy, vastly scaled-down, with the manipulator. When run slowly to reduce thermal drift, it could trace a Benchy within a 20-micrometer square, and had a resolution of about 50 nanometers.

He’s already used the micro-manipulator to couple an optical fiber with a laser, but [Diffraction Limited] has some other uses in mind, including maskless lithography (perhaps putting the stepper in “wafer stepper”), electrochemical 3D printing, focus stacking, and micromachining. For another promising take on small-scale manufacturing, check out the RepRapMicron.

Continue reading “Designing An Open Source Micro-Manipulator” →

Applying Thermal Lining To Rocket Tubes Requires A Monstrous DIY Spin-caster

September 2, 2025 by Donald Papp 18 Comments

[BPS.space] takes model rocketry seriously, and their rockets tend to get bigger and bigger. If there’s one thing that comes with the territory in DIY rocketry, it’s the constant need to solve new problems.

Coating the inside of a tube evenly with a thick, goopy layer before it cures isn’t easy.

One such problem is how to coat the inside of a rocket motor tube with a thermal liner, and their solution is a machine they made and called the Limb Remover 6000 on account of its ability to spin an 18 kg metal tube at up to 1,000 rpm which is certainly enough to, well, you know.

One problem is that the mixture for the thermal liner is extremely thick and goopy, and doesn’t pour very well. To get an even layer inside a tube requires spin-casting, which is a process of putting the goop inside, then spinning the tube at high speed to evenly distribute the goop before it cures. While conceptually straightforward, this particular spin-casting job has a few troublesome difficulties.

For one thing, the uncured thermal liner is so thick and flows so poorly that it can’t simply be poured in to let the spinning do all the work of spreading it out. It needs to be distributed as evenly as possible up front, and [BPS.space] achieves that with what is essentially a giant syringe that is moved the length of the tube while extruding the uncured liner while the clock is ticking. If that sounds like a cumbersome job, that’s because it is.

The first attempt ended up scrapped but helped identify a number of shortcomings. After making various improvements the second went much better and was successfully tested with a 12 second burn that left the tube not only un-melted, but cool enough to briefly touch after a few minutes. There are still improvements to be made, but overall it’s one less problem to solve.

We’re always happy to see progress from [BPS.space], especially milestones like successfully (and propulsively) landing a model rocket, and we look forward to many more.

Continue reading “Applying Thermal Lining To Rocket Tubes Requires A Monstrous DIY Spin-caster” →