A Complete Desktop PCB Etching Station

July 7, 2019 by Brian Benchoff 42 Comments

Right now you can get a custom circuit board delivered to your door in about a week for just a few dollars. There’s little reason to make your own circuit boards at home anymore, but when you need a board now, you want to have that capability. [Tuval Ben Dosa] designed a complete PCB etching station that is the perfect tool for making printed circuit boards at home. It’s got everything you need for the perfect etch, and with this setup you can make a board in hours instead of waiting for days.

The chemistry for any etching setup is important, and in recent years the entire community has moved from ferric chloride to copper chloride for a very good reason: you can recharge copper chloride etchant by bubbling oxygen (or air) through it, whereas ferric chloride is a one-use etchant.

The mechanical part of this build consists of an airtight glass food container sitting on top of a PCB heating element not unlike the heated bed of a 3D printer. Along with that is an I2C temperature sensor encased in a silicone tube, a stir bar, diaphram pump, and a few pumps to blow air into the etchant and pump out the chlorine gas generated. This is controlled by a small microcontroller with a UI consisting of just an encoder and OLED display.

If you’re looking for builds that will etch copper and brass at home, this has been something that has been done before. The Etchinator is a fantastic build capable of making everything from printmaking plates to printed circuit boards. That’s a build that requires a lot of work, and this small, compact etching station does everything you need without taking up too much space in the shop. Check out the video below.

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How To Turn A Chainsaw Into A Chopsaw

July 5, 2019 by Lewin Day 13 Comments

If you’re doing a lot of metal working, a chop saw is a great tool to have. It’s an easy and quick way to do a lot of neat, clean accurate cuts. [Making Stuff] wanted to do just that, but didn’t have a chop saw lying around. Instead, an old Stihl chainsaw was placed on the bench, and hacking ensued (Youtube link, embedded below).

To achieve this, it was necessary to source some parts and make some modifications to the chainsaw. The clutch bell was removed, and modified to mount a roller chain sprocket. An arm was then built, which mounted a pair of journal bearings at the far end. Another sprocket was installed at this end, along with a shaft which mounts the cutting wheel. Finally, a guard was fitted over the cutting wheel to give the build a semblance of safety.

[Making Stuff] notes that the chainsaw can readily be converted back to its standard purpose, needing only to refit the original parts and replace the modified clutch bell with a stock one. It’s a great way to get two tools out of one, and we’re sure it will prove useful in future projects.

If you’ve got a taste for wacky chop saws, check out this hard drive build. Video after the break.

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Sprucing Up A Bell & Howell Model 34 Oscilloscope

July 4, 2019 by Tom Nardi 20 Comments

We’ll admit it, in an era when you can get a four channel digital storage oscilloscope with protocol decoding for a few hundred bucks, it can be hard not to see the appeal of analog CRT scopes from decades past. Sure they’re heavy, harder to use, and less capable, but they just look so cool. Who could say no to having one of these classic pieces of gear on their bench?

[Cody Nybo] certainly couldn’t. Despite the fact that he already has a digital scope, he couldn’t pass up the chance to add a Bell & Howell Schools Model 34 from circa 1973 to his collection. It needed a bit of TLC before it could be brought back into service, but now it’s all fixed up and ready to put in some work. Not bad for a piece of gear with nearly a half-century on the clock.

The restoration of the Model 34 was aided by the fact that [Cody] got the original manual and schematics for the scope in the deal, which he was kind enough to scan and upload for the rest of the class to enjoy. Those of you who have worked on older electronics can already guess where the scope needed the most love: all the capacitors needed to be swapped out for fresh ones. He also found a few resistors that were out of spec, and the occasional bad solder joint here and there.

Even if you’re not looking to repair your own middle-aged oscilloscope, his pictures of the inside of Model 34 are fascinating. The scope was sold as a kit, so the construction is surprisingly simple and almost entirely point-to-point. Of course, there’s something of a trade-off at work: [Cody] says it won’t display much more than 2.5 MHz before things start getting wonky. But then again, that’s a more than reasonable frequency ceiling for audio work and most hobbyist projects.

Oscilloscopes have come a long way since the days when they had to draw out their readings on a piece of paper. While newer devices have all but buried the classic analog scope, a beauty like this would still have a place of honor in our lab.

Hacked Calipers Make Automated Measurements A Breeze

July 4, 2019 by Dan Maloney 22 Comments

Now, digital calipers with wired interfaces to capture the current reading are nothing new. But the good ones are expensive, and really, where’s the fun in plugging a $75 cable into a computer? So when [Max Holliday] was asked to trick out some calipers for automating data capture, he had to get creative.

[Max] found that cheap Harbor Freight digital calipers have the telltale door that covers a serial connector, making them a perfect target for hacking. A little Internet sleuthing revealed the pinout for the connector as well as some details on the serial protocol used by most digital calipers: 24-bit packets is six four-bit words. [Max] used his SAM32, a neat open-source board with both a SAMD51 and an ESP32 that can run CircuitPython. An inverting buffer interfaces the serial lines to the board, which is just the right size to mount on the back of the caliper head. It’s hard to tell how [Max] is triggering readings, but the SAM32 is mounted as a USB device and sends keystrokes directly to a spreadsheet – yes, with the ESP32 it could have been wireless, but his client specifically requested a wired setup. Taking multiple readings is easy now that the user never has to swap calipers for a pen.

Cheap calipers like these are pretty hackable – you can add Bluetooth, turn them into DROs for a milling machine, or even make them talk.

Spice With A Sound Card

July 3, 2019 by Al Williams 11 Comments

In years gone by, trying out a new circuit probably would have meant heating up a soldering iron. Solderless breadboards have made that even easier and computer simulation is easier still, but there’s something not quite as satisfying about building a circuit virtually. [Thedeuluiz] has a way to get some of the best of both worlds with the RTSpice project.

The idea is simple in concept, although not as simple in execution. The program does a Spice-like simulation of a circuit and can accept input and produce output from a PC’s sound card. Obviously, that means you can’t simulate RF circuits — at least not at the input and the output. It also means the simulation has to run lightning fast to keep up with the sound card sample rate. According to the author, it works best with modest circuits but exactly how big you can go will depend on your hardware.

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Hands-On: GreatFET Is An Embedded Tool That Does It All

July 2, 2019 by Mike Szczys 43 Comments

There’s a new embedded hacking tool on the scene that gives you an interactive Python interface for a speedy chip on a board with oodles of GPIO, the ability to masquerade as different USB devices, and a legacy of tricks up its sleeve. This is the GreatFET, the successor to the much loved GoodFET.

I first heard this board was close to launch almost a year ago and asked for an early look. When shipping began at the end of April, they sent me one. Let’s dig in for a hands-on review of the GreatFET from Great Scott Gadgets.

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Automatic Cut-Off Saw Takes The Tedium Out Of A Twenty-Minute Job

June 29, 2019 by Dan Maloney 26 Comments

For [Turbo Conquering Mega Eagle], the question was simple: Do I spend 20 minutes slaving away in front of a bandsaw to cut a bunch of short brass rods into even shorter pieces of brass rod? Or do I spend days designing and building an automatic cutoff saw to do the same job? The answer is obvious.

It’s only at the end of the video below that [TCME] reveals the need for these brass bits: they’re for riveting together the handles of knives he makes and sells. That makes the effort that went into his “Auto Mega Cut-O-Matic” a little easier to swallow, although we still think he ran afoul of this relevant XKCD. The saw is built out of scraps and odd bits using angle iron as a base and an electric die grinder to spin a cut-off wheel. A small gear motor feeds the brass rod down a guide tube until it hits a microswitch stop, which starts the cut cycle. Another motor swivels the saw to make the cut then moves it out of the way so the stock can advance. The impressive thing is that the only control mechanism is a series of microswitches, cams, levers, and springs – no Arduino needed. Heck, there’s not even a 555, which we find a refreshing change.

Yes, it’s overkill, but he had fun and made something pretty ingenious. [Turbo Conquering Mega Eagle] always has something interesting going on in the shop, and we couldn’t help but notice him using his aluminum-melting tea kettle to make some parts for this build.

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