Quickie USB Keyboard Device

June 12, 2016 by Elliot Williams 32 Comments

There are a ton of applications that we use that can benefit from keyboard shortcuts, and we use ’em religiously. Indeed, there are some tasks that we do so often that they warrant their own physical button. And the only thing cooler than custom keyboards are custom keyboards that you’ve made yourself.

Which brings us to [Dan]’s four-button Cherry MX USB keypad. It’s not really all that much more than four keyswitch footprints and an AVR ATmega32u4, but that plus some software is all you really need. He programs the Arduino bootloader into the chip, and then he’s using the Arduino Leonardo keyboard libraries. Bam! Check out the video below.

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Tiny Tiny RGB LED Displays

June 12, 2016 by Elliot Williams 17 Comments

Hackaday.io contributor extraordinaire [al1] has been playing around with small LEDs a lot lately, which inevitably leads to playing around with large groups of small LEDs. Matrixes of tiny RGB LEDs, to be precise.

First, he took 128 0404 SMD RGB LEDs (yes, 40 thousandths of an inch on each side) and crammed them onto a board that’s just under 37 mm x 24 mm. He calls the project 384:LED (after all, each of those 128 packages has three diodes inside). A microcontroller and the driver chips are located on a separate driver board, which piggy-backs via pin headers to the LED board. Of course, he had to use 0.05 inch headers, because this thing is really small.

Of course, no project is without its hitches. [al1] bought LEDs with the wrong footprint by mistake, so he had a bunch of (subtly different) 0404 LEDs left over. Time for an 8×8 matrix! 192:LED isn’t just the first project cut in half, though. It’s a complete re-design with a four-layer board and the microcontroller on the back-side. And as befits a scrounge project with lots of extreme soldering, he even pulled the microcontroller off of a cheap digital FM radio. Kudos!

We’re in awe of [al1]’s tiny, tiny hacking skills. Now it’s time to get some equally cool graphics up on those little displays.

Using WS2811 Chip To Drive Incandescent Lamps

June 12, 2016 by Elliot Williams 6 Comments

What makes the WS2812-style individually addressable pixel LEDs so inviting? Their rich colors? Nope, you can get RGB LEDs anywhere. Their form factor? Nope. Even surface-mount RGBs are plentiful and cheap. The answer: it’s the integrated controller. It’s just so handy to speak an SPI-like protocol to your LEDs — it separates the power supply from the data, and you can chain them to your heart’s desire. Combine this controller and the LEDs together in a single package and you’ve got a runaway product success.

But before the WS2812, there was the WS2811 — a standalone RGB controller IC. With the WS2812s on the market, nobody wants the lowly WS2811’s anymore. Nobody except [Michael Krumpus], that is. You see, he likes the old-school glow of incandescent, but likes the way the WS2812 strings are easy to drive and extend. So he bought a bag of WS2811s and put the two together.

The controller IC can’t handle the current that an incandescent bulb requires, so he added a MOSFET to do the heavy lifting. After linking a few of these units together, he discovered (as one does with the LED-based WS2812s eventually) that the switching transients can pull down the power lines, so there is a beefy capacitor accompanying each bulb.

He wanted each bulb to be independently addressable, so he only used the blue line of the RGB controller, which leaves two outputs empty. I’m sure you can figure out something to do with them.

Needless to say, we’ve seen a lot of WS2812 hacks here. It’s hard to pick a favorite. [Mike] of “mike’s electric stuff” fame built what may be the largest installation we’ve seen, and this hack that effectively projection-maps onto a randomly placed string of WS2812s is pretty cool. But honestly, no project that blinks or glows can go far wrong, right?

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Barb Makes Mechanical Pokey Finger With Filament Rivets

June 11, 2016 by Elliot Williams 11 Comments

We were trolling around Hackaday.io, and we stumbled on [Barb]’s video series called (naturally enough) “Barb Makes Things“. The plot of her videos is simple — Barb points a time-lapse camera at her desk and makes stuff. Neat stuff.

Two particularly neat projects caught our attention: a mechanical pointy-finger thing and the useful 3D-printing-filament rivets that she used to make it. (Both of which are embedded below.) The finger is neat because the scissor-like extension mechanism is straight out of Wile E. Coyote’s lab.

But the real winners are the rivets that hold it together. [Barb] takes a strand of filament, and using something hot like the side of a hot-glue gun, melts and squashes the end into a mushroom rivet-head. Run the filament through your pieces, mushroom the other end, and you’re set. It’s so obvious after seeing the video that we just had to share. (Indeed, a lot of cheap plastic toys are assembled using this technique.) It’s quick, removable, and seems to make a very low-friction pivot, which is something that printed pins-into-holes tends not to. Great idea!

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Zero Parts-Count Temperature Sensor

June 10, 2016 by Elliot Williams 24 Comments

Quick: What’s the forward voltage drop on a conducting diode? If you answered something like 0.6 to 0.7 V, you get a passing grade, but you’re going to have to read on. If you answered $V_F = \frac{T-T_0}{k}$ where T₀ and k are device-specific constants to be determined experimentally, you get a gold Jolly Wrencher.

[Jakub] earned his Wrencher, and then some. Because not only did he use the above equation to make a temperature sensor, he did so with a diode that you might have even forgotten that you have on hand — the one inside the silicon of a MOSFET — the intrinsic body diode.

[Jakub]’s main project is an Arduino-controlled electronic load that he calls the MightWatt, and a beefy power MOSFET is used as the variable resistance element. When it’s pulling 20 or 30 A, it gets hot. How hot exactly is hard to measure without a temperature sensor, and the best possible temperature sensor would be one that was built into the MOSFET’s die itself.

There’s a bunch of detail in his write-up about how he switches the load in and out to measure the forward drop, and how he calibrates the whole thing. It’s technical, but give it a read, it’s good stuff. This is a great trick to have up your sleeve.

And if you’re in the mood for more stupid diode tricks, we recommend using them as solar cells or just stringing a bunch of them together to make a thermal camera.

Hackaday Prize Entry: Waterspace, A Floating Hackerspace Lab

June 9, 2016 by Elliot Williams 7 Comments

It’s a boat! It’s a hackerspace! It’s a DIY research platform and an art gallery! It’s Boat Lab!

[Andrew Quitmeyer] lead a project in the Philippines that was nominally charged with making an art and technology space. After a few days brainstorming, four groups formed and came up with projects as wide-ranging as a water-jet video screen and a marine biology lab. What did they have in common? They were all going to take place on a floating raft hackerspace in a beautiful body of water in Manila.

This is a really crazy meta-project, and any of the sub-projects would be worth their own blog post. Even more so is the idea itself — building a floating hackerspace is just cool. The write-up on Hackaday.io linked above is pretty comprehensive, and the “Waterspace” book talks a bit more about the overarching process. Boat Lab is a great entry into the Citizen Science phase of the Hackaday Prize 2016.

But we also love the idea of hackerspaces in non-traditional places. The Cairo Hackerspace is working on a van-based space. And now we’ve seen a boat. What other mobile hackerspace solutions are out there? We’d love to hear!

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Pen-Plotter Firmware Written Completely In Ada

June 9, 2016 by Elliot Williams 43 Comments

[Fabian Chouteau] built a plotter out of CD-ROM parts. Yawn, you say? Besides being a beautiful physical build, this one has a twist. He wrote the software and firmware for the entire project himself, in Ada.

Ada is currently number two on our list of oddball programming languages that should be useful for embedded programming. It’s vaguely Pascal-y, but with some modern object-oriented twists. It was developed for safety-critical, real-time embedded systems (by the US Department of Defense), and is used in things like airplanes, rockets, and the French TGV trains. If that sounds like overkill for your projects, [Fabian]’s project shows that it’s still very tractable.

In his GitHub, he re-implements the GRBL G-code generator and then writes a GUI front-end for it. In his writeup, he mentions that the firmware and its simulator for the front-end use exactly the same code which is quite a nice trick, and guarantees no (firmware) surprises when moving from the modelled device to the real thing.

We looked quickly around for Ada resources and came up with: GNAT, the GNU Ada compiler, and its derivatives: GNAT for ARM (STM32-flavor), ARM-Ada (LPC21xx flavor), AVR-Ada, and MSP430-Ada.

Any of you out there use Ada in embedded work? We’d love to hear your thoughts.

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