Tool Hacks

3037 Articles

A Magic Eye Tube Does All The Work In This Kit

March 11, 2025 by 16 Comments

We’re used to low cost parts and a diversity of electronic functions to choose from in our projects, to the extent that our antecedents would be green with envy. Back when tubes were king, electronics was a much more expensive pursuit with new parts, so designers had to be much more clever in their work. [Thomas Scherrer OZ2CPU] has just such a design on his bench, it’s a Heathkit Capaci-Tester designed in 1959, and we love it for the clever tricks it uses.

It’s typical of Heathkits of this era, with a sturdy chassis and components mounted on tag strips. As the name suggests, it’s a capacitor tester, and it uses a magic eye tube as its display. It’s looking for short circuits, open circuits, and low equivalent resistance, and it achieves this by looking at the loading the device under test places on a 19 MHz oscillator. But here comes that economy of parts; there’s no rectifier so the circuit runs on an AC HT voltage from a transformer, and that magic eye tube performs the task of oscillator as well as display.

He finds it to be in good condition in the video below the break, though he removes a capacitor placed from one of the mains input lines to chassis. It runs, and confirms his test capacitor is still good. It can’t measure the capacitance, but we’re guessing the resourceful engineer would also have constructed a bridge for that.

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Hacking Digital Calipers For Automated Measurements And Sorta-Micron Accuracy

March 6, 2025 by 14 Comments

We’ll take a guess that most readers have a set of digital calipers somewhere close to hand right now. The cheapest ones tend to be a little unsatisfying in the hand, a bit crusty and crunchy to use. But as [Matthias Wandel] shows us, these budget tools are quite hackable and a lot more precise than they appear to be.

[Matthias] is perhaps best known around these parts for making machine tools using mainly wood. It’s an unconventional material for things like the CNC router he loves to hate, but he makes it work through a combination of clever engineering and a willingness to work within the limits of the machine. To assess those limits, he connected some cheap digital calipers to a Raspberry Pi by hacking the serial interface that seems to be built into all of these tools. His particular calipers output a pair of 24-bit words over a synchronous serial connection a couple of times per second, but at a level too low to be read by the Pi. He solved this with a clever resistor ladder to shift the signals to straddle the 1.8 volt transition on the Pi, and after solving some noise problems with a few strategically placed capacitors and some software debouncing, he was gathering data on his Pi.

Although his setup was fine for the measurements he needed to make, [Matthias] couldn’t help falling down the rabbit hole of trying to milk better resolution from the calipers. On paper, the 24-bit output should provide micron-ish resolution, but sadly, the readings seem to fluctuate rapidly between two levels, making it difficult to obtain an average quickly enough to be useful. Still, it’s a good exercise, and overall, these hacks should prove handy for anyone who wants to dip a toe into automated metrology on a budget.

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Piggyback Board Brings Touch Sensing To USB Soldering Iron

March 5, 2025 by 20 Comments

The current generation of USB-powered soldering irons have a lot going for them, chief among them being portability and automatic start and stop. But an iron that turns off in the middle of soldering a joint is a problem, one that this capacitive-touch replacement control module aims to fix.

The iron in question is an SJ1 from Awgem, which [DoganM95] picked up on Ali Express. It seems well-built, with a sturdy aluminum handle, a nice OLED display, and fast heat-up and cool-down. The problem is that the iron is triggered by motion, so if you leave it still for more than a second or two, such as when you’re soldering a big joint, it turns itself off. To fix that,[DoganM95] designed a piggyback board for the OEM controller with a TTP223 capacitive touch sensor. The board is carefully shaped to allow clearance for the existing PCB components and the heater cartridge terminals, and has castellated connections so it can connect to pads on the main board. You have to remove one MOSFET from the main board, but that’s about it for modifications. A nickel strip makes contact with the inside of the iron’s shell, turning it into the sensor plate for the TTP223.

[DoganM95] says that the BA6 variant of the chip is the one you want, as others have a 10-second timeout, which would defeat the purpose of the mod. It’s a very nice bit of design work, and we especially like how the mod board nests so nicely onto the OEM controller. It reminds us a little of those Quansheng handy-talkie all-band mods.

Inexpensive Powder Coating

March 4, 2025 by 17 Comments

[Pete] had a friend who would powder coat metal parts for him, but when he needed 16 metal parts coated, he decided he needed to develop a way to do it himself. Some research turned up the fluid bed method and he decided to go that route. He 3D printed a holder and you can see how it all turned out in the video below.

A coffee filter holds the powder in place. The powder is “fluidized” by airflow, which, in this case, comes from an aquarium pump. The first few designs didn’t work out well. Eventually, though, he had a successful fluid bed. You preheat the part so the powder will stick and then, as usual, bake the part in an oven to cure the powder. You can expect to spend some time getting everything just right. [Pete] had to divert airflow and adjust the flow rate to get everything to work right.

With conventional powder coating, you usually charge the piece you want to coat, but that’s not necessary here. You could try a few other things as suggested in the video comments: some suggested ditching the coffee filter, while others think agitating the powder would make a difference. Let us know what you find out.

This seems neater than the powder coating guns we’ve seen. Of course, these wheels had a great shape for powder coating, but sometimes it is more challenging.

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A man in black glasses and a black t-shirt has his arms resting on a grey workbench. Between his opened hands are the two halves of a copper ice press. They are fist-sized copper cylinders. The lower half has large spiraling grooves to aid in the release of excess water from the ice being formed as it melts.

Make Ice Spheres In A Copper Press

March 2, 2025 by 12 Comments

Perfectly clear ice spheres are nifty but can be a bit tricky to make without an apparatus. [Seth Robinson] crafted a copper ice press to make his own.

Copper is well-known for its thermal conductivity, making it a perfect material for building a press to melt ice into a given shape. Like many projects, a combination of techniques yields the best result, and in this case we get to see 3d printing, sand casting, lost PLA casting, lathe turning, milling, and even some good old-fashioned sanding.

The most tedious part of the process appears to be dip coating of ceramic for the lost PLA mold, but the finished result is certainly worth it. That’s not to say that any of the process looks easy if you are a metal working novice. Taking over a week to slowly build up the layers feels a bit excruciating, especially compared to 3D printing the original plastic piece. If you’re ever feeling discouraged watching someone else’s awesome projects, you might want to stick around to the end when [Robinson] shows us his first ever casting. We’d say his skill has improved immensely over time.

If you’re looking for something else to do with casting copper alloys, be sure to checkout this bronze river table or [Robinson’s] copper levitation sphere.

Thanks to [DjBiohazard] for the tip!

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The Bus Pirate 5 Sure Can Glitch

March 1, 2025 by 2 Comments

Own a Bus Pirate 5? Now, it can do power glitching, thanks to [Matt Brugman’s] demo and contributions to the stock code. This is also a great demo of Bus Pirate’s capabilities and programmability! All you need is the Bus Pirate and a generic Arduino – load a glitch-vulnerable code example into the Arduino, get yourself a generic FET-based glitching setup, and you too can play.

The Arduino board outputs data over UART, and that’s used as a trigger for the Bus Pirate’s new glitch feature – now mainline, thanks to [Matt]’s pull request. It’s pretty feature-complete, too — all parameters are configurable, it can vary the glitching interval, as one would want, and the code checks for success conditions so that it can retry glitching automatically.

In this demo, it only took six consecutive attempts to successfully glitch the ATMega328P – wouldn’t you know it, the code that got glitched was pulled almost wholesale from an IoT device. Glitching remains an underappreciated vector for reverse-engineering, and there’s really no shortage of hacks it allows you to do – get yourself a FET, a Bus Pirate, or maybe just an ESP8266, and join the glitching-aware hackers club!

Want to know more about the Bus Pirate 5? Check out our hands-on review of the hacker multi-tool from last year.

To Test A (Smart) LED

February 24, 2025 by 14 Comments

Adding LEDs to a project used to be enough to make it cool. But these days, you need arrays of addressable multi-color LEDs, and that typically means WS2812B or something similar. The problem is that while it was pretty easy to test garden-variety LEDs, these devices can be a bit harder to troubleshoot. [Gokux] has the answer, as you can see in the video below.

Testing these was especially important to [Gokux] because they usually swipe the modules from other modules or LED strips. The little fixture sends the correct pulses to push the LED through several colors when you hold it down to the pads.

However, what if the LED is blinking but not totally right? How can you tell? Easy, there’s a reference LED that changes colors in sync with the device under test. So, if the LEDs match, you have a winner. If not… well, it’s time to desolder another donor LED.

This is one of those projects that you probably should have thought of, but also probably didn’t. While the tester here uses a Xiao microcontroller, any processor that can drive the LEDs would be easy to use. We’d be tempted to breadboard the tester, but you’d need a way to make contact with the LED. Maybe some foil tape would do the trick. Or pogo pins.

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