Simple Hardware Store Hack Keeps Your PCBs Right Where You Want Them

January 16, 2025 by Dan Maloney 27 Comments

Sometimes it’s the simplest hacks that make the biggest impact.

Take these DIY magnetic PCB vises for example. Sure, you can go out and buy purpose-built tools, but [Dylan Radcliffe] just made a trip to the hardware store for some nuts and bolts. He chose 3/8″-16 bolts, which would probably be around M10 for the rest of the world. The head of each bolt is ground flat so a ceramic disc magnet can be attached to it with CA glue, while the head of the bolt gets a plastic washer glued to it. Another plastic washer gets glued to a nut, which when threaded onto the bolt provides the light clamping force needed to hold a PCB. Make four of those and stick them to a steel plate with the magnets, and you can stop chasing your boards around the bench with a soldering iron.

As much as we like this idea — and we do; we’re heading to Home Depot to buy the needed parts this very evening — we can think of a few useful modifications. With a long bolt and two nuts rather than one, you could make a set of vises that are easily adjustable along the Z-axis. This could prove useful to those of us working under a microscope. Also, rather than making the bolts the magnetic part we bet you could lay down a flexible magnetic sheet, the kind you can feed into a printer to roll your own fridge magnets. We suspect that would hold the bolts firmly enough for most work while still allowing easy repositioning. We’d also favor flange nuts over plain hex nuts, to give a larger clamping area. We’d still include the plastic washers, though, or possibly switch to rubber ones.

There’s more than one way to skin this cat, of course, especially if you’ve got a Harbor Freight nearby and a well-stocked Lego bin.

Game boy with custom cartridge mounted on car dashboard

A Game Boy Speedometer, Just Because You Can

January 15, 2025 by Heidi Ulrich 10 Comments

From a practical standpoint, [John] may be correct that his recent creation is the “world’s worst digital dash”, but we’re still oddly enamored with the idea of using a Nintendo Game Boy as a digital speedometer. Pulling it off meant interfacing the handheld with the vehicle’s CAN bus system, so whether you’re into retro gaming or car hacking, this project has something to offer.

Showing real-time vehicle speed on the Game Boy sounds like it should be relatively easy, but the iconic game system wasn’t exactly built for such a task. Its 2 MHz CPU and 160×144 pixel dot-matrix screen were every kid’s dream in 1989, but using it as a car dashboard is pushing it. To bridge that gap, [John] designed two custom circuit boards. One interfaces with the Game Boy, intercepting its memory requests and feeding it data from a microcontroller. The other processes the CAN bus signals, translating speed information into a form the Game Boy can display. [John] used inexpensive tools and software to read the CAN bus data, and used GBDK-2020 to write the software in C. His video goes in great detail on how to do this.

Months of work have gone into decoding the Game Boy’s data bus and creating a schematic for the interface board. Tricking the Game Boy into thinking it was loading a game, while actually displaying incoming speed data. The screen’s low resolution and slow refresh rate rendered it barely readable in a moving vehicle. But [John]’s goal wasn’t practicality — it was just proving it could be done.

Want to dive deep into the Game Boy? Have you seen the Ultimate Game Boy talk?

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Bit-Banging The USB-PD Protocol

January 10, 2025 by Bryan Cockfield 13 Comments

For one-off projects, adding a few integrated circuits to a PCB is not too big of a deal. The price of transistors is extremely low thanks to Moore and his laws, so we’re fairly free to throw chips around like peanuts. But for extremely space-constrained projects, huge production runs, or for engineering challenges, every bit of PCB real estate counts. [g3gg0] falls into the latter group, and this project aims to remove the dedicated USB-PD module from a lighting project and instead bit-bang the protocol with the ESP32 already on the board.

The modern USB power delivery (PD) protocol isn’t quite as simple as older USB ports that simply present a 5V source to whatever plugs itself into the port. But with the added complexity we get a lot more capability including different voltages and greater power handling capabilities. The first step with the PD protocol is to communicate with a power source, which requires a 1.2V 600kHz signal. Just generating the signal is challenging enough, but the data encoding for USB requires level changes to encode bits rather than voltage levels directly. With that handled, the program can then move on to encoding packets and sending them out over the bus.

After everything is said and done, [g3gg0] has a piece of software that lets the ESP32 request voltages from a power supply, sniff and log PD communication, and inject commands with vendor defined messages (VDM), all without needing to use something like a CH224K chip which would normally offload the USB-PD tasks. For anyone looking to save PCB space for whatever reason, this could be a valuable starting point. To see some more capabilities of the protocol, check out this USB-PD power supply that can deliver 2 kW.

Retrotechtacular: Soldering The Tek Way

January 9, 2025 by Dan Maloney 40 Comments

For a lot of us, soldering just seems to come naturally. But if we’re being honest, none of us was born with a soldering iron in our hand — ouch! — and if we’re good at soldering now, it’s only thanks to good habits and long practice. But what if you’re a company that lives and dies by the quality of the solder joints your employees produce? How do you get them to embrace the dark art of soldering?

If you’re Tektronix in the late 1970s and early 1980s, the answer is simple: make in-depth training videos that teach people to solder the Tek way. The first video below, from 1977, is aimed at workers on the assembly line and as such concentrates mainly on the practical aspects of making solid solder joints on PCBs and mainly with through-hole components. The video does have a bit of theory on soldering chemistry and the difference between eutectic alloys and other tin-lead mixes, as well as a little about the proper use of silver-bearing solders. But most of the time is spent discussing the primary tool of the trade: the iron. Even though the film is dated and looks like a multi-generation dupe from VHS, it still has a lot of valuable tips; we’ve been soldering for decades and somehow never realized that cleaning a tip on a wet sponge is so effective because the sudden temperature change helps release oxides and burned flux. The more you know.

The second video below is aimed more at the Tek repair and rework technicians. It reiterates a lot of the material from the first video, but then veers off into repair-specific topics, like effective desoldering. Pro tip: Don’t use the “Heat and Shake” method of desoldering, and wear those safety glasses. There’s also a lot of detail on how to avoid damaging the PCB during repairs, and how to fix them if you do manage to lift a trace. They put a fair amount of emphasis on the importance of making repairs look good, especially with bodge wires, which should be placed on the back of the board so they’re not so obvious. It makes sense; Tek boards from the era are works of art, and you don’t want to mess with that.

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Perfecting 20 Minute PCBs With Laser

January 5, 2025 by Al Williams 40 Comments

Normally, you have a choice with PCB prototypes: fast or cheap. [Stephen Hawes] has been trying fiber lasers to create PCBs. He’s learned a lot which he shares in the video below. Very good-looking singled-sided boards take just a few minutes. Fiber lasers are not cheap but they are within range for well-off hackers and certainly possible for a well-funded hackerspace.

One thing that’s important is to use FR1 phenolic substrate instead of the more common FR4. FR4 uses epoxy which will probably produce some toxic fumes under the laser.

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Blast Away The Flux — With Brake Cleaner?

December 26, 2024 by Dan Maloney 74 Comments

Can you use brake cleaner for flux removal on PCBs? According to [Half Burnt Toast], yes you can. But should you? Well, that’s another matter.

In our experience, flux removal seems to be far more difficult than it should be. We’ve seen plenty of examples of a tiny drop of isopropyl alcohol and a bit of light agitation with a cotton swab being more than enough to loosen up even the nastiest baked-on flux. If we do the same thing, all we get is a gummy mess embedded with cotton fibers smeared all over the board. We might be doing something wrong, or perhaps using the wrong flux, but every time we get those results, we have to admit toying with the idea of more extreme measures.

The LED bar graphs were not a fan of the brake cleaner.

[Toast] went there, busting out a fresh can of brake cleaner and hosing down some of the crustier examples in his collection. The heady dry-cleaner aroma of perchloroethylene was soon in the air, and the powerful solvent along with the high-pressure aerosol blast seemed to work wonders on flux. The board substrate, the resist layer, and the silkscreen all seemed unaffected by the solvent, and the components were left mostly intact; one LED bar graph display did a little melty, though.

So it works, but you might want to think twice about it. The chlorinated formula he used for these tests is pretty strong stuff, and isn’t even available in a lot of places. Ironically, the more environmentally friendly stuff seems like it would be even worse, loaded as it is with acetone and toluene. Whichever formula you choose, proceed with caution and use the appropriate PPE.

What even is flux, and what makes it so hard to clean? Making your own might provide some answers.

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Rudolph’s Sleigh On A North Pole PCB

December 20, 2024 by Heidi Ulrich 18 Comments

Each Christmas, [Adam Anderson], [Daniel Quach], [Johan Wheeler], and [Gustav Abrahamsson] (going by ‘the Janky Jingle Crew’)—set themselves the challenge of outdoing their previous creations. Last year’s CH32 Fireplace brought an animated LED fire to life with CH32V003 microcontrollers.

This year, they’ve gone a step further with the North Pole Circuit, a holiday project that combines magnetic propulsion, festive decorations, and a bit of engineering flair. Inspired by a miniature speedway based on Friedrich Gauss’ findings, the North Pole Circuit includes sleighs and reindeer that glide along a custom PCB track, a glowing village with flickering lights, and a buzzer to play Christmas tunes.

The propulsion system works using the Lorentz force, where vertical magnets interact with PCB traces to produce motion. A two-phase design, similar to a stepper motor, ensures smooth operation, while guard rails maintain stability on curves. A separate CH32V003 handles lighting and synchronized jingles, creating a cohesive festive display. As we mentioned in the article on their last year’s creation, going from a one-off to a full batch will make one rethink the joy of repetitive production. Consider the recipients of these tiny Christmas cards quite the lucky ones. We deem this little gift a keeper to put on display when Christmas rolls around again.

This annual tradition highlights the Crew’s knack for combining fun and engineering. Curious about the details or feeling inspired to create your own? Explore the full details and files on their GitHub.