Author: Dan Maloney

3293 Articles

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.

Big Chemistry: Glass

March 5, 2025 by 12 Comments

Humans have been chemically modifying their world for far longer than you might think. Long before they had the slightest idea of what was happening chemically, they were turning clay into bricks, making cement from limestone, and figuring out how to mix metals in just the right proportions to make useful new alloys like bronze. The chemical principles behind all this could wait; there was a world to build, after all.

Among these early feats of chemical happenstance was the discovery that glass could be made from simple sand. The earliest glass, likely accidentally created by a big fire on a sandy surface, probably wasn’t good for much besides decorations. It wouldn’t have taken long to realize that this stuff was fantastically useful, both as a building material and a tool, and that a pinch of this and a little of that could greatly affect its properties. The chemistry of glass has been finely tuned since those early experiments, and the process has been scaled up to incredible proportions, enough to make glass production one of the largest chemical industries in the world today.

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CNC Router And Fiber Laser Bring The Best Of Both Worlds To PCB Prototyping

March 4, 2025 by 22 Comments

Jack of all trades, master of none, as the saying goes, and that’s especially true for PCB prototyping tools. Sure, it’s possible to use a CNC router to mill out a PCB, and ditto for a fiber laser. But neither tool is perfect; the router creates a lot of dust and the fiberglass eats a lot of tools, while a laser is great for burning away copper but takes a long time to burn through all the substrate. So, why not put both tools to work?

Of course, this assumes you’re lucky enough to have both tools available, as [Mikey Sklar] does. He doesn’t call out which specific CNC router he has, but any desktop machine should probably do since all it’s doing is drilling any needed through-holes and hogging out the outline of the board, leaving bridges to keep the blanks connected, of course.

Once the milling operations are done, [Mikey] switches to his xTool F1 20W fiber laser. The blanks are placed on the laser’s bed, the CNC-drilled through holes are used as fiducials to align everything, and the laser gets busy. For the smallish boards [Mikey] used to demonstrate his method, it only took 90 seconds to cut the traces. He also used the laser to cut a solder paste stencil from thin brass shim stock in only a few minutes. The brief video below shows the whole process and the excellent results.

In a world where professionally made PCBs are just a few mouse clicks (and a week’s shipping) away, rolling your own boards seems to make little sense. But for the truly impatient, adding the machines to quickly and easily make your own PCBs just might be worth the cost. One thing’s for sure, though — the more we see what the current generation of desktop fiber lasers can accomplish, the more we feel like skipping a couple of mortgage payments to afford one.

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Deep Space DX Hack Chat

March 3, 2025 by 6 Comments

Join us on Wednesday, March 5 at noon Pacific for the Deep Space DX Hack Chat with David Prutchi!

In the past 70-odd years, the world’s space-faring nations have flung a considerable amount of hardware out into the Void. Most of it has fallen back into Earth’s gravity well, and a lot of what remains is long past its best-by date, systems silenced by time and the harsh conditions that rendered these jewels of engineering into little more than space flotsam.

Luckily, though, there are still a few spacecraft plying the lonely spaces between the planets and even beyond that still have active radios, and while their signals may be faint, we can still hear them. True, many of them are reachable only using immense dish antennas.

join-hack-chatNot every deep-space probe needs the resources of a nation-state to be snooped on, though. David Prutchi has been listening to them for years using a relatively modest backyard antenna farm and a lot of hard-won experience. He’s been able to bag some serious DX, everything from rovers on Mars to probes orbiting Jupiter. If you’ve ever wanted to give deep space DX a try, here’s your chance to get off on the right foot.

Our Hack Chats are live community events in the Hackaday.io Hack Chat group messaging. This week we’ll be sitting down on Wednesday, March 5 at 12:00 PM Pacific time. If time zones have you tied up, we have a handy time zone converter.

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Hackaday Links: March 2, 2025

March 2, 2025 by 4 Comments

It’s been quite a week for asteroid 2024 YR4, which looked like it was going to live up to its “city killer” moniker only to be demoted to a fraction of a percent risk of hitting us when it swings by our neighborhood in 2032. After being discovered at the end of 2024, the 55-meter space rock first popped up on the (figurative) radar a few weeks back as a potential risk to our home planet, with estimates of a direct strike steadily increasing as more data was gathered by professional and amateur astronomers alike. The James Webb Space Telescope even got in on the action, with four precious hours of “director’s discretionary” observation time dedicated to characterizing the size and shape of the asteroid before it gets too far from Earth. The result of all this stargazing is that 2024 YR4 is now at a Level 1 on the Torino Scale of NEO collision risk, with a likely downgrade to 0 by the time the asteroid next swings through again in 2028. So, if like us you were into the whole “Fiery Space Rock 2032” thing, you’ll just have to find something else to look forward to.

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Custom Frame Grabber Gets Vintage Kodak Digital Camera Back In The Game

February 25, 2025 by 6 Comments

What do you do with a four-megapixel monochrome digital camera from the 90s that needed a dedicated PC with a frame grabber card to do anything useful? Easy — you turn it into a point-and-shoot by building your own frame grabber.

At least that’s what [Frost Sheridan] did with a vintage Kodak MegaPlus 4.2i, a camera that was aimed at the industrial and scientific market at a time when everyone was still using film for snapshots. Making this workhorse ride again meant diving into the manual, luckily still available after all these years, and figuring out what pins on the 68 pin connector would be useful. [Frost] worked out the pins for serial commands plus the 10-bit parallel interface, although he settled for the eight most significant bits to make things simpler. A Teensy with some extra RAM and a serial interface chip takes care of sending commands to the camera and pulling pixels off the parallel interface, and a 128×160 LCD provides a much-needed viewfinder.

With a battery pack mounted the whole thing is reasonably portable, if a bit of a chore to use. It’s worth the effort, though; the picture quality is fantastic, with a wide dynamic range and plenty of contrast. Hats off to [Frost] for bringing this beauty back to life without making any permanent modifications to it.

PCB Dielectric Constant Measurements, Three Ways

February 25, 2025 by 6 Comments

FR4 is FR4, right? For a lot of PCB designs, the answer is yes — the particular characteristics of the substrate material don’t impact your design in any major way. But things get a little weird up in the microwave range, and having one of these easy methods to measure the dielectric properties of your PCB substrate can be pretty handy.

The RF reverse-engineering methods [Gregory F. Gusberti] are deceptively simple, even if they require some fancy test equipment. But if you’re designing circuits with features like microstrip filters where the permittivity of the substrate would matter, chances are pretty good you already have access to such gear. The first method uses a ring resonator, which is just a PCB with a circular microstrip of known circumference. Microstrip feedlines approach but don’t quite attach to the ring, leaving a tiny coupling gap. SMA connectors on the feedline connect the resonator to a microwave vector network analyzer in S21 mode. The resonant frequencies show up as peaks on the VNA, and can be used to calculate the effective permittivity of the substrate.

Method two is similar in that it measures in the frequency domain, but uses a pair of microstrip stubs of different lengths. The delta between the lengths is used to cancel out the effect of the SMA connectors, and the phase delay difference is used to calculate the effective permittivity. The last method is a time domain measurement using a single microstrip with a couple of wider areas. A fast pulse sent into this circuit will partially reflect off these impedance discontinuities; the time delay between the reflections is directly related to the propagation speed of the wave in the substrate, which allows you to calculate its effective permittivity.

One key takeaway for us is the concept of effective permittivity, which considers the whole environment of the stripline, including the air above the traces. We’d imagine that if there had been any resist or silkscreen near the traces it would change the permittivity, too, making measurements like these all the more important.

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