Why spend time etching circuit boards and applying solder masks when all you really need is a rollerball pen and some paper? That’s what University of Illinois professors [Jennifer Lewis and Jennifer Bernhard] were asking when they set off to research the possibility of putting conductive ink into a standard rollerball pen.

The product of their research is a silver nanoparticle-based ink that remains liquid while inside a pen, but dries on contact once it is applied to a porous surface such as paper. Once dry, the ink can be used to conduct electricity just like a copper trace on a circuit board, making on the fly circuit building a breeze.

Previous ink-based circuit construction was typically done using inkjet printers or airbrushing, so removing the extra hardware from the process is a huge step forward. The team even has some news for those people that think the writable ink won’t hold up in the long run. The ink is surprisingly quite resilient to physical manipulation, and they found that it took folding the paper substrate several thousand times before their ink pathways started to fail.

While we know this is no substitute for a nicely etched board, it would be pretty cool to prototype a simple circuit just by drawing out the connections on a piece of paper – we can’t wait to see this come to market.

Here’s a step-by-step guide for printing etch resist directly to copper clad boards. Two methods of making printed circuit boards at home have long dominated as the favorites; using photo-resist, and the toner-transfer method. The latter involves printing board artwork on a laser printer and then ironing it onto the copper clad. We’ve seen some efforts to print toner directly to the copper, or to use ink to adhere toner and then heat fuse it, but this hack is the first one we remember seeing that uses an inkjet printer directly.

The best reason inkjet printing isn’t often used is do to the ink’s iability to protect copper from the etchant. This method uses MISPRO ink that is pigment based and will resist the acid. An Epson Stylus Photo R260 printer was chosen because you can get refillable printer cartridges which work with the ink, and they’re fairly easy to modify. In order to feed substrate through the device it needs some physical alteration to make room for the thickness of the material, and an ATtiny13 has been added to trick one of the sensors.

Unfortunately we didn’t find photos of the printed resist. But there is source code available for the tiny13 if you do give this a try.

[Thanks Pavlejo]

This is an inkjet print head made using a RepRap. The manufacturing process is both simple and ingenious. It uses a vibrating piezo buzzer to pump printing liquid through a tiny nozzle. The red disc seen above is exactly the same diameter as the piezo that resides behind it. There is a hole offset from the center to feed ink in between the two discs. Take a look at the test footage after the break.

To make the nozzle a hole was cut in the plastic disc, then a pin inserted and the whole thing was covered with hot glue. The next step was to remove the pin and shave down the glue until the narrow aperture is open. [Adrian Bowyer] is still in the testing phase for this assembly, but once he gets the bugs worked out he plans to test it with a heating element so that it can print using wax and other materials that are liquid when hot.

[Vik] tipped us off about this one after seeing the printable transistors from the other day.

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[Jeri Ellsworth] continues her experiments with electroluminescence, this time she’s making EL ink. The ink she’s looking for is Zinc Sulfate in a solution. The process she chose is to re-dope some glow powder so that it can be excited by the field around an AC current. In her video (embedded after the break) she talks about the chemical properties she’s after by detailing a cubic lattice of zinc and sulfur atoms with an added copper atom (adding that atom is a process called doping).

The quick and dirty synopsis of the experiment starts by washing the glow powder with dish soap to acquire zinc sulfide crystals. Then she combined copper sulfate and zinc shavings from the inside of a modern penny to yield copper metal and zinc sulfate suspended in solution. That was mixed with the zinc sulfide from the glow powder washing and doped with a little more copper sulfate. The excess liquid is poured off, the test tube is capped with glass frit, and the whole thing hits the kiln to start the reaction. The result glows when excited by alternating current, but could have been improved by adding chlorine atoms into the mix.

We’re excited every time we see one of [Jeri's] new chemistry hacks. We’d love to see more so if you’ve come across interesting chemistry experiments during your Internet travels, please let us know about them. Just make sure you have some idea of what you’re doing when working with chemicals… safety first.

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The txtBomber is a high-tech graffiti printer developed by [Felix Vorreiter]. Details are a bit scarce but the video clip after the break proves that this works quite well. [Felix] admits this is Arduino powered but we’re going to have to guess at the rest of the setup from the pictures. He says there are built-in-pens so we’d bet there’s a felt-tip type of thing going on and those look like seven solenoids that actuate them. He posted a picture of the handle side of the device and we can make out two wheels that are connected to LEGO gears. This tracks movement of the txtBomber across a surface in order to synchronize the printing process. There’s no sign of an LCD so it looks like you have to pre-program the messages before you go out into the field.

This is akin to the Chalkbot, but the messages that leaves wash away with the rain. This one seems like it might get you into some trouble if you get caught leaving permanent tags around the neighborhood.

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The number one and number two things asked after presentation of our DIYDTG were…
“How does it hold up in the wash?”
and…
“How did you change out the inks?”
While we’ve explained the first several times (regular ink washes out, DTG ink gets a little lighter but survives) we can hopefully answer the second with a tutorial.

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We’ll ask it again, why aren’t we building our own printers? We’re building 3d printers, CNC mills, and hacking the ink cartridges on commercial printers. What does it really take to build say a 300 dpi black and white printer? Something that lets you clean and service the print head rather than throwing it out when the ink reservoir is empty?

Someone has set out to answer these question with the Openprinter project. If this interests you, join up and start the revolution. RepRap had simple beginnings and maybe it’s time to take the army of self-replicating 3D printers and use them to print parts for 2D printers that don’t drive us crazy.

[Photo credit]

[via LostScrews]

Xerox has announced a breakthrough in printable circuits. They’ve developed a conductive ink called “silver bullet” that can be printed on many different types of substrate to create circuits. The key part of the new ink is its lower melting point. Plastic film substrate melts at 150 degrees Celsius but the ink is liquid when ten degrees cooler to avoid damaging the film. This begs the question: how do you then solder components to the circuit?

The benefits of printable circuitry are obvious. Aside from cheaper and easier RFID, disposable circuits like greeting cards, and fabric-based electronics, we’re hoping this will facilitate more environmentally friendly PCB fabrication. That really depends on the ink’s production process and the resilience of the resulting circuitry.

[via Gizmodo]