Testing The Efficiency Of PCB Etchants

May 8, 2014 by Brian Benchoff 73 Comments

etch In the interest of the scientific method [Feynmaniac] (great name, btw) over on Instructables has posted a little experiment on something we all, no doubt, care about: putting PCB traces in copper clad boards with the most common etchants out there.

The experiment used the ‘ol standard, ferric chloride, and the safe, inexpensive newcomer, vinegar, hydrogen peroxide, and table salt. Finding the most efficient mixture of ferric chloride is easy: just use what’s in the bottle. The vinegar and H2O2 requires some stoichiometry, though, and [Feynmaniac] calculated that with an 8% acetic acid solution and the most commonly available 3% peroxide solution, a 2:3 ratio of peroxide to vinegar is the best. Salt to taste, or until everything turns green.

Four copper clad boards were used for the test, masked off in a ‘barcode’ pattern. Two methods of applying the etchant were used: either rubbing the etchant on with a sponge, or immersing the boards in a bath of the etchant being tested.

In terms of speed, ferric chloride was by far the fastest, with 3 minutes until the board was etched using the rubbing method, or 10 minutes when simply immersed. Vinegar/peroxide took longer with 11 minutes rubbed, and 20 minutes immersed. No differences in the quality of the etch were noticed.

While ferric chloride was by far the fastest etchant, it does have the downside of being environmentally unfriendly and fairly expensive. The vinegar and peroxide etchant is safe, cheap, and can be found in any grocery store on the planet.

This experiment didn’t test other common etchants like HCl and H202, or cupric chloride (which is is the byproduct of HCl and H202). Still, it’s a good confirmation that the vinegar and peroxide method actually works, in case you were wondering.

Building EL Displays On A PCB

April 24, 2014 by Brian Benchoff 26 Comments

Elecrolumiscent displays have seen a huge swing in popularity recently, but only in limited forms like EL wire or flat EL panels. You can, of course, cut and bend these wires and panels to suit any purpose, but custom shaped EL displays are just the bee’s knees. They’re not hard to fabricate, either: with cheap custom PCBs, all it takes to make custom EL panels is just a few chemicals.

[Nick]’s method of fabricating custom EL displays uses an exposed copper layer on a PCB you’d pick up from OSHpark or any of the random board houses in China. The process consists of designing a display – be it a few letters, pixels, or a seven-segment arrangement. The display ‘stack’ is a layer of painted-on dialectric, a phospor, and finally a translucent conductive ink that connects the display segments to ground. It looks like an extremely easy process, and from the pictures it looks like [Nick] is making some EL displays of reasonable quality.

[Nick]’s work was inspired by the grand poobah of homebrew electrolumiscent displays, [Jeri Ellsworth], who managed to make a similar EL pixel on a PCB. [Nick]’s display looks great, though, and with a little work some custom segment displays should be very possible.

Copper Oxide Thermoelectric Generator Can Light An LED

March 26, 2014 by Mathieu Stephan 54 Comments

On Hackaday, we usually end up featuring projects using building blocks (components, platforms…) that can be bought on the market. We however don’t show many hacks that rely on basic physics principles like the one shown in the picture above.

In the video embedded below, [nylesteiner] explains that copper oxide can be formed when heating a copper wire using a propane flame. When two oxidized wires are placed in contact with each other, an electrical current is produced when one wire is heated much hotter than the other. The trade-off is that the created thermocouple generates a small voltage but a ‘high’ current. However, when you cascade 16 junctions in series you can generate enough voltage to light up an LED. Even though the complete system isn’t particularly efficient at converting heat into electricity, the overall result is still quite impressive in our opinion. We advise our readers to give a look at [nylesteiner]’s article and blog to discover his interesting adventures.

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Authentic Blue Blueprints

March 21, 2014 by Brian Benchoff 31 Comments

blue

At one point in history, blueprints were actually blue. Now, if you even see a dead tree version of plans or assemblages, they’re probably printed off with a plotter or large format printer. You can, however, make your own blueprints at home, as [Tyler] shows us in his Hackaday Project.

Back in the olden days, master drawings were traced onto large sheets of transparent film. These master prints were then laid over paper prepared with Potassium Ferricyanide and Ferric Ammonium Citrate to create an insoluble Prussian Blue background for the prints. Developing is easy – just expose the transparent positive and undeveloped paper to UV light, in the form of fluorescent bulbs or the sun.

[Tyler] began his blueprint creation process by getting a few design sketches of the RSI Aurora and Nautilus, editing them on a computer, and printing them out on transparency sheets. A solution of equal parts Potassium Ferricyanide and Ferric Ammonium Citrate were painted onto a piece of paper and allowed to dry. Exposing was a simple matter of laying the transparency over the undeveloped paper and setting it out in the sun for 20 minutes or so. After that, it’s a simple matter of washing off the unexposed chemicals and letting the newly created blueprint dry.

It’s a simple technique, but also very, very cool. Not exactly practical, given a plotter can spit out an architectural or assembly drawing of any building, vehicle, or device in a few minutes, but just the ticket for art pieces or extremely odd engineers.

Thanks [Sarah] for sending this in.

Billboard Advertises Engineering School, Manufactures Potable Water

March 13, 2014 by Kristina Panos 24 Comments

It’s a remarkable thing when ad agencies manage to help people in the course of advertising. The University of Technology and Engineering Peru (UTEC) was looking for ways to increase enrollment. They went to the Peruvian offices of agency DraftFCB and came away with the idea to install a billboard that converts Lima’s water-saturated coastal desert air into potable water.

Perhaps the only downside is that it requires electricity, and not just for those cool neon water drops. There are five generators that capture the humidity and use reverse osmosis to purify the water. Each of these units has a tank that holds 20L. From there, the clean water is aggregated in a main tank and can be collected from a faucet at the base of the billboard. In just three months, the billboard produced over 9,000L (2500 gallons) of potable water for people who would otherwise draw polluted water from wells.

We love to see hacks that help. Use your powers for good, like re-purposing humid air and pollution. Make the jump to see a short video and an artist’s conception of the billboard’s innards.

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Fetching Etchings For Stainless Steel

March 9, 2014 by Kristina Panos 25 Comments

What do you do when you have a 10-gallon brew kettle (or any other stainless steel or aluminium thing) with no volume markings (or Hack a Day logos)? If you’re [Itsgus], you use science to etch some markings with a few household items and a 9V and you call it a day.

[Itsgus] used 1/4c vinegar and 1/4tsp of salt to form an electro-etchant and applied it with a Q-tip connected to the negative terminal of a 9V. He used tape to connect a wire between the positive terminal and the kettle. The vinegar dissolves the salt, creating negatively charged ions. Connected correctly to a 9V, the process removes metal where the current flows. If you were to connect it in reverse, you would add a small amount of metal.

The process only takes a few seconds. When the etchant starts to sizzle and bubble, Bob’s your uncle. Even though the stainless steel’s natural coat re-oxidizes over the etches, you should probably wash that thing before you brew. If you prefer adding metal to removing it, try electroplating copper on the cheap.

Here’s The Dirt On Printing With Pollution

March 5, 2014 by Kristina Panos 34 Comments

[Anirudh] and his friends were sitting around reminiscing about India. In particular, they recalled riding around in auto-rickshaws in stifling heat, watching their skin turn black from the exhaust. They started thinking about all of the soot and pollution in crowded cities the world over and wondered whether the stuff could be re-purposed for something like printer ink. That’s how they came up with their soot/pollution printer.

They created a soot-catching pump which they demonstrate with a burning candle. The pump mixes the soot particles with rubbing alcohol and an oil substrate and sends the ink to an HP C6602 inkjet cartridge. They used [Nicolas C Lewis]’s print head driver shield for Arduino to interface with the cartridge, turning it into a 96dpi printing head that uses only five pins.

[Anirudh] and his friends plan to design a carbon separator using charged plates to capture the soot particles from pollution sources and filter out dust. Be sure to check out their demonstration video after the jump.

Update: In response to [Hirudinea]’s comment about mining the carbon from cars, [Anirudh] is now looking for collaborators (tinkerers, filmmakers, DIY enthusiasts) to move forward with the idea of re-purposing carbon. Email him at anirudhs@mit.edu.

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