The Fastest Rise Time In The West: Making A Truly Quick Pulse Edge

October 3, 2016 by 62 Comments

When we are taught about oscillators as newbie engineers, we are shown a variety of waveforms on an oscilloscope or in a textbook. This is a sine wave, they say, this is a sawtooth, this is a square wave, and so on. We’re taught to look at the lines on the screen as idealised, a square wave is truly square, and the transition from low to high voltage and back again is instantaneous.

In most cases this assumption is harmless. If we look into the subject a little deeper we learn that what seemed an instantaneous cliff-face is in fact a very steep slope, but when a circuit does its business in milliseconds there is usually no harm in ignoring a transition time measured in nanoseconds. The glue logic for your Arduino project can take its time.

Sometimes though, the rise time of a logic transition is important. The application that prompted this article was the measurement of oscilloscope bandwidth by looking at how quickly the ‘scope catches up with a pulse that exceeds its bandwidth, for example. When the instrument can happily measure the transition times of all your usual  pulse generators, something out of the ordinary is called for. So it’s worth taking a look at the rise times you’d expect from everyday circuitry, examining a few techniques for generating rise times that are much faster.
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Maker Faire Multicolor And Multi Material 3D Printing

October 3, 2016 by 25 Comments

The next frontier of desktop 3D printing is multi-material and multi-color prints. Right now, you can buy a dual toolhead for a Lulzbot, and dual toolheads from other companies exist, although they are a bit rare. In the next few years, we’re going to see a lot of printers able to print dissolvable supports and full-color 3D printers.

Printing in more than one color is almost here, but that doesn’t mean we’re on the cusp of a complete revolution. Multi-material printing is lagging a little bit behind; you’ll be able to print two colors of PLA next year, but printing an object in PLA and ABS is going to be a bit tricky. Printing something in PLA and nylon will be very hard. Color mixing, likewise, will be tricky. We can do it, the tools are getting there, but think of this year as a preview of what we’ll be doing in five years.

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Scanning Parts Into KiCad

October 3, 2016 by 37 Comments

You do not know how to make a PCB unless you can make your own parts. [Jan] knows this, but like everyone else he checked out the usual online sources for a footprint for an SD card socket before making his own. It turns out, this SD card socket bought from an online marketplace was completely undocumented. Not only was an Eagle or KiCad footprint unavailable, but CAD files showing the dimensions of the part were non-existent. A solution had to be devised.

Instead of taking calipers and finely measuring all the pads on this SD card socket – a process that would surely fail – [Jan] decided to use a flatbed scanner to trace out the part. The part was placed on the glass and scanned at 300 dpi with a convenient reference object (a public transport card) in the same picture. This picture was imported into a CAD package, scaled to the correct ratio, and exported as a DXF. Since KiCad readily accepts importing DXFs, the CAD file was easily accessed, traced over, and a new part created.

From start to finish, making the footprint for this no-name, off-brand SD card socket took fifteen minutes. That’s nothing compared to the time it would take to manually measure each of the pads, draw a footprint, and print out the footprint at 1:1 scale to see if it matched up several times. It’s awesome work, and a great reminder that the best tools are usually right in front of you.

Hackaday Prize Entry: FPGAs For The Raspberry Pi Zero

October 2, 2016 by 14 Comments

The Raspberry Pi is the Arduino of 2016, and that means shields, hats, add-ons, and other fun toys that can be plugged right into the GPIO pins of a Pi. For this year’s Hackaday Prize, [Valentin] is combining the Pi with the next age of homebrew computation. He’s developed the Flea Ohm, an FPGA backpack or hat for the Pi Zero.

The Flea Ohm is based on Lattice’s ECP5 FPGA featuring 24k LUTs and 112kB BRAM. That’s enough for some relatively interesting applications, but the real fun comes from the added 32MB or 128MB of SDRAM, a micro SD card slot, USB + PS/2 host port and an LVDS output.

The combination of Raspberry Pis and FPGAs are extremely interesting and seem to be one of the best FPGA learning platforms anyone can imagine. Another Hackaday Prize entry, the ZinqBerry does a similar trick, but instead of a Pi hat, the ZinqBerry drops a Xilinx Zynq with an FPGA and ARM Cortex A9 core onto a board with Ethernet, HDMI, and USB.

If it’s a Flea or a Zinq, the age of FPGA’d Raspberry Pis is quickly approaching, and hopefully we’ll see them as finalists in the Hackaday Prize. You can check out a video of the Flea Ohm below.

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A Desk Lamp Solder Fume Extractor

October 2, 2016 by 18 Comments

Those of us who have spent a lifetime building electronic projects have probably breathed more solder smoke than we should. This is not an ideal situation as we’ve probably increased our risk of asthma and other medical conditions as a result.

It has become more common over the years to see fume extraction systems and filters as part of the professional soldering environment, and this trend has also started to appear in the world of the home solderer. As always, where commercial products go the hardware hacker will never be far behind. We’ve seen people producing their own soldering fume filters using computer fans.

A particularly neat example comes via [Engineer of None], who has posted an Instructable and the YouTube video shown below the break for a filter mounted on a desk lamp. A toaster is used to heat a piece of acrylic. The softened plastic is then shaped to fit the contours of the lamp. The lamp’s articulated arm is perfect for placing light and fume extraction exactly where it is needed. It’s not the most complex of hacks, but we’d have one like it on our bench without a second thought. We would probably add an activated carbon filter to ours though.

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Hackaday Links: October 2, 2016

October 2, 2016 by 32 Comments

Hey Elon, three weeks ago I was in Burning Man in the Nevada desert and after I dug myself a nice K-hole I notice that Mars is a lot like the Nevada desert which got me thinking that if we can live here we can live on Mars but then I realized that Mars really isn’t a lot like the Nevada desert because there are toilets here but if we could build toilets on Mars it would be a lot like the Nevada desert? This week Elon Musk unveiled the Interplanetary Transport System at the International Astronautical Congress in Guadalajara. Instead of filling the room with industry experts the highlights of the Q&A session consisted of a woman who wanted to give Elon a kiss onstage and some guy who was super, super high. Discussion of the technical feasibility of a big, heavy window on the Heart of Gold has not appeared anywhere. Zero thought has been given to the consequences of building a civilization consisting entirely of the wealthiest 1% of Earth’s population. I fully support the Interplanetary Transport System; I’m going because this planet sucks.

[FoamieNinja] over on /r/radiocontrol is experimenting with single bladed propellers. Single bladed propellers are the most efficient way of pushing air behind an engine but haven’t really seen widespread use because they’re really weird, and I don’t know if you can do a variable pitch prop like this. You can find these types of props rarely on big-sized aircraft such as vintage J-3 Cubs sporting a 40HP engine. I haven’t seen them on anything bigger.

Next weekend is the Open Hardware Summit in Portland, Oregon. Hackaday is going to be there, and there’s a BringAHack at OSH Park on Thursday. Last year at the summit, the Open Source Hardware Certification was announced. This year, OSHWA is ready to launch their certification program. The takeaway from last year is that Open Hardware Certification will be free, self-certifying, with penalties based on fines for non-compliance.

The ESP32 is here, but most of them are still in a shipping container somewhere in the Pacific. Here’s a breakout board for the Espressif ESP-WROOM-02.

The J-Core is a clean room, open source CPU and SOC. Currently, it’s only implemented in VHDL until someone has a ton of money to burn on an ASIC. Now, the J-Core is supported by Linux. That makes an ASIC just a bit more likely. Thanks [Stefano] for the tip.

MakerBot is not at the New York Maker Faire this year. This is the greatest proof of the imminent failure of MakerBot, but it does deserve some context. In 2009, MakerBot demoed their first printer, the Cupcake, at the New York Maker Faire in Queens, NY. This was, by any reasonable historical reckoning, the introduction of a simple, easy to use, consumer 3D printer to the masses. The current trend of cheap desktop printers began seven years ago this weekend. MakerBot was so successful that it can be argued that Make:, the magazine and the faire, has tried to take credit for the consumer 3D printer ecosystem, simply because they hosted the launch of the Cupcake. Over the years, everyone has tried to ride MakerBot’s coattails. Since then, a few things happened. Last month, MakerBot introduced a new line of (China-manufactured) 3D printers, and they don’t have a booth. The reasons for this could be that Maker Faire is horrifically expensive for any vendor, and MakerBot is going to be at CES next year anyway, but this is it. The MakerBot obituary was not premature. We won.

Multimeter Probe Goes Full Circle

October 2, 2016 by 7 Comments

You’ve probably seen tweezers act as test probes for a multimeter or other instrument. Some electronics testing tweezers even have the multimeter built right in. Tools like these are especially handy for working with surface mount components. [Bweed2] found a probe made by E-Z hook that kept a fixed distance you can set with a thumbwheel. It looked good, but the $70-$80 price tag seemed too much.

Employing hacker ingenuity, he turned to a drafting compass. You know, the tool you use to draw circles. He picked up one for about $10 and then got some cheaper compasses to scavenge their needles (the compass usually only has one needle since the other side holds a pencil). The result was a useful set of adjustable probes.

Once you have the idea, it is a pretty simple project. Immobilize the knee of the compass with glue, connect some wires and–for extra points–add some red and black heat shrink to make it pretty.

Want to make a more classic SMD tweezer? Here’s one we’ve covered before. If you’d rather use your feet and your ears with your probes, you might be interested in these.