LED Fabrication from Wafer to Light

Building a circuit to blink an LED is the hardware world’s version of the venerable “Hello, world!” program — it teaches you the basics in a friendly, approachable way. And the blinky light project remains a valuable teaching tool right up through the hardware wizard level, provided you build your own LEDs first.

For [emach1ne], the DIY LED was part of a Master’s degree course and began with a slice of epitaxial wafer that goes through cleaning, annealing, and acid etching steps in preparation for photolithography. While gingerly handling some expensive masks, [emach1ne] got to use some really cool tools and processes — mask aligners, plasma etchers, and electron beam vapor deposition. [emach1ne] details every step that led to a nursery of baby LEDs on the wafer, each of which was tested. Working arrays were cut from the wafer and mounted in a lead frame, bonded with gold wires, and fiat lux.

The whole thing must have been a great experience in modern fab methods, and [emach1ne] should feel lucky to have access to tools like these. But if you think you can’t build your own semiconductor fab, we beg to differ.

[via r/engineering]

Graphene Grown on Semiconductors Big Step Toward Manufacturability

No modern technology has been met with more hype than graphene. These single-layer sheets of carbon promise everything from incredibly efficient power grids to more advanced electronics to literal elevators to space. Until now, though, researchers have yet to produce graphene sheets or ribbons in a reliable way. Researchers at the University of Wisconsin at Madison and the US Department of Energy Argonne National Laboratory have done just that, growing graphene nanoribbons on the surface of a germanium crystal.

By using a germanium crystal as a substrate, the researchers have found a directionality to the way these graphene nanoribbons form. This has been a problem for researchers experimenting with graphene microelectronics in the past; labs experimenting with making transistors out of carbon nanotubes found growth is highly unpredictable. The controlled growth of graphene nanoribbons opens the door to more precise fabrication, something that is necessary for microelectronics fabrication.

Synthesis of nanoribbons this small have not been possible before. Because germanium itself is a semiconductor – and was used for the first transistor – this discovery may pave the way for the creation of graphene-based circuits grown using the same semiconductor fabrication processes used today.

Fail of the Week: Oil Expeller and Hasty PCB Layout


This Fail of the Week is a twofer. On the left we have an attempt to heat the output of an oil expeller. After a bountiful crop of sunflower seeds [Mark] picked up the oil expeller to make is own cooking oil. He tried to use the soldering gun as a heat source but after just a couple of minutes of on-time it melted the soldering iron’s plastic case. He’s looking for an alternate heat source but we wonder why he can’t just ditch the plastic and bolt this to a heat sink?

To the right is the product of hasty PCB layout. [Andrew] needed a USB to GPIO converter to use with his Android stick. He had built several of these before, etching the PCBs himself. But now he didn’t have the time to do his own etching and figured he could lay out a revision of the board and have it fabbed. Turns out this isn’t the time saver he had hoped. Problems with the location of silk screen labels aren’t a huge deal, but the ‘V’ in the board where his USB connector is located blocked any cable he tried to plug in. A bit of cutting solved that but he also had to deal with spring terminals whose leads wouldn’t fit the diameter of holes drilled in the board. We always print out the Gerbers and compare the footprints to our parts before submitting to the fab house. But we’re not sure we would have caught the USB cable clearance issue doing it that way. What checklists do you use before submitting your own boards?

2013-09-05-Hackaday-Fail-tips-tileFail of the Week is a Hackaday column which runs every Wednesday. Help keep the fun rolling by writing about your past failures and sending us a link to the story — or sending in links to fail write ups you find in your Internet travels.

[Ladyada’s] thoughts on quick-turn and small-run PCB houses

So you’ve mastered your PCB layout software, and it’s time to make the board. But if you don’t want to etch your own you’ve got to decided where to have it fabricated. There’s a slew of services out there, most of which you cannot afford, but the short list of those you can is still pretty long. We think this set of PCB fabrication house reviews will help you make your choice.

[Ladyada] — aka [Limor Fried] — knows what she’s talking about. She owns Adafruit Industries and has done the lion’s share of designing the many kits and items they sell. If you’re going to charge money for something it better work right, and that involves lots of prototypes. But even if you don’t need a quick turn-around or numerous testing boards the post is helpful as she also covers some of the batch producers we’re already familiar with. These include DorkBot PDX and BatchPCB to name a couple.

[via Reddit]

3d printing saves the day for time-lapse photography

Several of us here at Hackaday have discussed how much we’d like to have some tools, like a 3d printer, but just can’t justify the cost. What would we make? Why do we really need one? Why don’t we just bother [Brian Benchoff] who already has one to make us parts instead. That’s usually how the conversation goes.

[Alexander Weber] gave us another little reason to drop in our “list of reasons we need a 3d printer” list with this little hack. He wanted to play with CHDK but found the camera’s battery unable to stay alive for longer than 2 hours. There is a commercially available adapter to allow you to plug into the wall, but the cost was outrageous. At least it is outrageous to someone who already owns a 3d printer. We just need a few hundred more dollars worth of reasons to justify that sweet 3d printer we’ve been pining over.

[via Adafruit]

Minimalist AVR programmer is just fab!

Whether you’re burning a new bootloader to an Arduino board, or doing away with a bootloader to flash Atmel chips directly, an in-system programmer (ISP) is an indispensable tool for working with AVR microcontrollers. If cost has held you back, it’s no longer an excuse: FabISP is a barebones USB-based AVR programmer that can be pieced together for about ten bucks.

FabISP was created by [David Mellis] as a product of MIT’s Fab Lab program, which provides schools with access to design and manufacturing tools based around a core set of fabrication capabilities, so labs around the world can share results. But the FabISP design is simple enough that you don’t need a whole fab lab. It’s a small, single-sided board with no drilling required; the parts are all surface-mounted, but not so fine-pitched as to require reflow soldering. Easy!

There’s still the bootstrap problem, of course: you need an AVR programmer to get the firmware onto the FabISP. This would be an excellent group project for a hackerspace, club or school: if one person can provide the initial programmer to flash several boards, each member could etch and assemble their own, have it programmed, then take these out into the world to help create more. We must repeat!

[Thanks Juan]

A new contender in home fabbing


Purple Crayon is a new entry into the home fabricating arena.  Shown above, with it’s makers [Konrad] and [Aaron], it’s set to compete with RepRap and Cupcake. It looks to be bigger than Cupcake, but smaller than the reprap. There aren’t many details available on their site, but we’re sure there will be soon. They do state that it should retail for less than $1,000.