Fixing Tools With 3D Printers

March 24, 2013 by Brian Benchoff No comments

saw

Over at the Manchester Hackerspace, [Bob] has been busy getting a 30-year-old bandsaw up and running. The saw worked great, but it was missing a fence, making straight cuts difficult to say the least. The solution, of course, was to build a new fence, and [Bob] decided to capitalize on his hackerspace’s workshop by making a new fence with a 3d printer.

[Bob] began by taking careful measurements of the saw’s table and the channel running down the length of it. These measurements were plugged into OpenSCAD, and after a few iterations, [Bob] had an extremely well-fitting profile a fence could be attached to.

With the profile down, [Bob] created a new part in OpenSCAD that would hold an aluminum angle piece. This was attached to the plastic parts with screws, and the entire assembly clamps down to the saw with the help of a few 5mm bolts. For a machine that is usually dedicated to making 3D printer parts and Yoda heads, [Bob] did a great job making good use of his 3D printer.

Printed Vacuum Pump Muffler Quiets The Lab

March 21, 2013 by Mike Szczys 46 Comments

printed-vacuum-pump-muffler

[Joel] made a brilliant improvement to his shop. If you think about it, most folks would hear a loud vacuum pump and either tolerate it or put in some ear plugs. But [Joel] heard a loud vacuum pump and thought: hey, I can fix that! His solution was to design and print his own muffler.

He did a bit of research on the topic and found that design complexity runs the gamut based on the application. For instance, you don’t want to affect the airflow of a vehicle’s exhaust too much or you will take a horsepower (and efficiency) hit for it. In this case the vacuum pump making all the noise has a relatively low airflow so that is not a concern. What he ended up doing is designing a baffle that will help cushion the vibrations in the airy by piping it through a maze of channels. The end result drops from about 92 dB to 82 dB. That might not seem like much, but decibel measurements aren’t linear so it ends up having a great effect. Hear for yourself in the video after the break.

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Testing Caps With A DIY ESR Meter

March 16, 2013 by Brian Benchoff 21 Comments

There’s a problem with collecting old tube amps and vintage electronics – eventually the capacitors in these machines will die. It’s not an issue of a capacitor plague that causes new electronics to die after a few years; with time, just about every capacitor will dry out, rendering antique electronics defective. The solution to getting old gear up and running is replacing the capacitors, but how do you know which ones are good and which are bad? With [Paulo]’s DIY ESR meter, of course.

An ideal capacitor has a zero equivalent series resistance, and failure of a capacitor can be seen as an increase in its ESR. Commercial ESR meters are relatively cheap, but [Paulo] was able to build one out of a 555 chip, a small transformer, and a few other miscellaneous components.

The entire circuit is built on stripboard, and if you’re lucky enough to find the right parts in your random parts bin, you should be able to build this ESR meter with components just laying around.

EEPROM Hack Unlocks Crippled Features In Agilent Multimeter And LCR Meter

March 14, 2013 by Mike Szczys 31 Comments

u1241a-agilent-hack

[Gnif] was doing what any good hacker does… poking around the insides of one of his tools to see how it works. While in there, he discovered that an EEPROM hack could make the Agilent U1241A function like the U1242A.

If you’re into this kind of thing the Rigol 1052e hack should have already popped to mind. That was a firmware crippled device that, when unlocked, made the cheaper model behave the same ways as it’s $400 more expensive sibling. This doesn’t have quite the same impact, as the price difference is somewhere between $20-$100. Still, this stuff is just cool, right?

A few posts down in the thread linked above [Gnif] shares the story of how he found the hack. After shorting the i2c lines of the EEPROM while powering up the meter he was able to see that the device initializes a lot of its values to 0xFF when it can’t find the stored data. The next step was to use an STM32 board to dump the EEPROM contents. With the backup file stored safely he started changing values and reflashing the chip. Through this process he discovered that switching one byte from 0x01 to 0x02 enabled the higher model’s features. It also works for upgrading the U1732C to the U1733C feature set.

Camera Adapter For A Microscope

March 12, 2013 by Mike Szczys 21 Comments

camera-adapter-for-stereo-microscope

[Steve] really has a nice microscope setup in his lab now that he built a video camera adapter for his stereo microscope. The image above shows the magnified view of the circuit board on the LCD screen behind it. This lets him work without needing to be in position to look through the eye pieces. The hack is a perfect complement to the custom stand he fabricated for the scope.

The camera attachment can be seen attached to the right lens of the scope. It’s an old security camera which he already had on hand. The stock lens wasn’t going to bring the picture into focus, but he had some different optics on hand and one of them fit the bill perfectly. The rest of the project involves fabricating the adapter ring on his lathe. It slips perfectly over the eyepiece and even allows him a bit of adjustment to get the focal length right. The best view of this is shown off in the video after the break.

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PCB Stencils For $200

March 11, 2013 by Brian Benchoff 26 Comments

stencil

There’s some really cool stuff to find if you wander around a Michaels craft shop or Hobby Lobby long enough. Recently, [Ben] picked up a craft cutter – a small vinyl cutter-like device meant for scrapbooking and other crafty endevours. He’s using this machine to create solder paste stencils that are better than any laser cut stencil he’s used before.

Like a build we’ve seen before, [Ben] is using a desktop-sized vinyl cutter, the Sihouette Portrait, with 4 mil Mylar. After converting the relevent layers of a Gerber file into .SVG files, [Ben] loaded up Robocut to cut very, very small holes in his solder stencil. The results are great; much better than a laser would cut Mylar, and good enough to apply paste to a few hundred boards at least.

While [Ben] is using his stencils to apply solder paste, we’re wondering if a similar process could be used to apply a UV-curing solder mask to home-fabbed boards. That would allow for some very professional-looking boards to be produced with a turnaround time of just a few hours.

Hard Drive Centrifuge For Sensitizing Copper Clad Boards

March 9, 2013 by Mike Szczys 26 Comments

hdd-to-apply-light-sensitive-ink

We would wager that most of the home etched PCB projects we see around here use the toner transfer method. But the next most popular technique is to use photosensitive ink which resists the etching acid once it has been exposed to light. Most people buy what are called pre-sensitized boards, but you can also get ink to make your own. [Jardirx] does this, and uses an old hard drive to apply an even layer of the light-sensitive ink.

The narration and subtitles of the video found after the break are both in Portuguese, but it’s not hard to figure out what’s going on here. He begins by using double-sided foam tape to secure the piece of copper clad board to the hard drive platters. You’ll want to center it as best as you can to keep the vibrations to a minimum. From there [Jardirx] applies a coating of the ink using a brush. The image above is what results. So as not to get ink everywhere, he then lowers a soda bottle with the bottom cut off to catch the excess. Power up the drive for a few seconds and the board will have a nice even layer ready for a trip through a UV exposure box.

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