Hackaday Links: December 10, 2017

December 10, 2017 by Brian Benchoff 14 Comments

We have a contest going on right now challenging you to do the most with a coin cell. There are already quite a few interesting entries, and a few Hackaday writers are getting into the action by asking the question, ‘how do you open up a coin cell?’. The first thoughts were to open a lithium coin cell up while submerged in oil, but eBay came to the rescue with the cases for CR2025 cells. Of course that’s a thing.

Also falling into the, ‘of course that’s a thing’ category, there’s a project on Hackaday.io to execute arbitrary code on a calculator. A small group of calculator hackers have discovered an exploit on a line of Casio calculators running the obscure nX-U8/100 architecture. Right now, there’s not much to the project — just an LCD filled with bits of memory. However, this is a project we’re keenly watching, and we can’t wait to see what comes of it.

Hold onto your butts, because the ultimate multimeter is here. [Dave Jones] of the EEVBlog has released the 121GW Multimeter on Kickstarter. What’s cool about this meter? SD card logging, the ability to send data over Bluetooth, a 15V diode test voltage, a burden voltage display, and a whole bunch of hackable features. If you have a Fluke on your Christmas list, you would do well to check out the 121GW.

Also on Kickstarter, a new LattePanda board has been released. What’s a LattePanda? It’s a small single board computer built around a low-voltage Intel processor. This board features an Intel m3-7Y30 processor, comparable to the processor you’d get in a proper laptop that doesn’t have an i3, 8 gigs of DDR3, 64 gigs of eMMC, 802.11ac, BlueTooth 4.2, USB 3.0 with a Type C connector, HDMI, and a whole bunch of GPIOs. Yes, it runs Windows (but why would you?). If you need a somewhat beefy x86 system in a small form factor, there ‘ya go.

We’ve seen 3D printed remote-controlled airplanes, but never one this big. The guys at Flite Test printed a 1.6 meter Spitfire. It’s got flaps, it’s got retracts, and it’s friggin’ huge. The files for the print came from 3DLabPrint, and it flies beautifully, despite being a Spitfire. Want to see the video? Here ya go.

Fully-functional Oscilloscope On A PIC

December 10, 2017 by Bryan Cockfield 15 Comments

When troubleshooting circuits it’s handy to have an oscilloscope around, but often we aren’t in a lab setting with all of our fancy, expensive tools at our disposal. Luckily the price of some basic oscilloscopes has dropped considerably in the past several years, but if you want to roll out your own solution to the “portable oscilloscope” problem the electrical engineering students at Cornell produced an oscilloscope that only needs a few knobs, a PIC, and a small TV.

[Junpeng] and [Kevin] are taking their design class, and built this prototype to be inexpensive and portable while still maintaining a high sample rate and preserving all of the core functions of a traditional oscilloscope. The scope can function anywhere under 100 kHz, and outputs NTSC at 30 frames per second. The user can control the ground level, the voltage and time scales, and a trigger. The oscilloscope has one channel, but this could be expanded easily enough if it isn’t sufficient for a real field application.

All in all, this is a great demonstration of what you can accomplish with a microcontroller and (almost) an engineering degree. To that end, the students go into an incredible amount of detail about how the oscilloscope works since this is a design class. About twice a year we see a lot of these projects popping up, and it’s always interesting to see the new challenges facing students in these classes.

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Making Rubber Stamps With OpenSCAD

December 10, 2017 by Tom Nardi 21 Comments

There’s an old saying that goes “If you can’t beat ’em, join ’em”, but around these parts a better version might be “If you can’t buy ’em, make ’em”. A rather large portion of the projects that have graced these pages have been the product of a hacker or maker not being able to find a commercial product to fit their needs. Or at the very least, not being able to find one that fit their budget.

GitHub user [harout] was in the market for some rubber stamps to help children learn the Armenian alphabet, but couldn’t track down a commercially available set. With a 3D printer and some OpenSCAD code, [harout] was able to turn this commercial shortcoming into a DIY success story.

Rather than having to manually render each stamp, he was able to come up with a simple Bash script that calls OpenSCAD with the “-D” option. When this option is passed to OpenSCAD, it allows you to override a particular variable in the .scad file. A single OpenSCAD file is therefore able to create a stamp of any letter passed to it on the command line. The Bash script uses this option to change the variable holding the letter, renders the STL to a unique file name, and then moves on to the next letter and repeats the process.

This procedural generation of STLs is a fantastic use of OpenSCAD, and is certainly not limited to simple children’s stamps. With some improvements to the code, the script could take any given string and font and spit out a ready to print mold.

With a full set of letter molds generated, they could then be printed out and sealed with a spray acrylic lacquer. A mold release was applied to each sealed mold, and finally they were filled with approximately 200ml of Simpact urethane rubber from Smooth-On. Once the rubber cures, he popped them out of the molds and glued them onto wooden blocks. The end result looks just as good as anything you’d get from an arts and crafts store.

The process used here is very similar to the 3D printed cookie molds we’ve covered recently, though we have to assume these little morsels would not be nearly as tasty. Of course, if you had access to a small CNC machine you could cut the stamps out of the rubber directly and skip the mold step entirely.

Tapping Into A Ham Radio’s Potential With SDRPlay

December 10, 2017 by Dan Maloney 18 Comments

Software-defined radios are great tools for the amateur radio operator, allowing visualization of large swaths of spectrum and letting hams quickly home in on faint signals with the click of a mouse. High-end ham radios often have this function built in, but by tapping into the RF stage of a transceiver with an SDR, even budget-conscious hams can enjoy high-end features.

With both a rugged and reliable Yaesu FT-450D and the versatile SDRPlay in his shack, UK ham [Dave (G7IYK)] looked for the best way to link the two devices. Using two separate antennas was possible but inelegant, and switching the RF path between the two devices seemed clumsy. So he settled on tapping into the RF stage of the transceiver with a high-impedance low-noise amplifier (LNA) and feeding the output to the SDRPlay. The simple LNA was built on a milled PCB. A little sleuthing with the Yaesu manual — ham radio gear almost always includes schematics — led him to the right tap point in the RF path, just before the bandpass filter network. This lets the SDRPlay see the signal before the IF stage. He also identified likely points to source power for the LNA only when the radio is not transmitting. With the LNA inside the radio and the SDRPlay outside, he now has a waterfall display and thanks to Omni-Rig remote control software, he can tune the Yaesu at the click of a mouse.

If you need to learn more about SDRPlay, [Al Williams]’ guide to GNU Radio and SDRPlay is a great place to start.

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Rock Out With The Nod Bang

December 10, 2017 by Will Sweatman 7 Comments

In our years here on Hackaday, we’ve seen our fair share of musical hacks. They even have their own category! (Pro Tip – you can find it under the drop down menu in the Categories section). But this one takes the cake. [Andrew Lee] is a student at New York University who had a task of creating a project for his physical computing class. In about 60 days time; he went from dinner napkin sketch to working project. The project is quite interesting – he’s made an instrument that plays music as you move your head.

It works as you would expect. An accelerometer in the user’s headphones feed data to an arduino. There are four (3D printed of course) buttons that are used to select the the type of audio being played. The operation goes as such:

Press button.
Bang head.

[Andrew] speaks of a particular satisfaction of hearing the music play in sync with the rhythm of head movement. Be sure to check out the video below to see the Nod Bang in action.

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Spice Up Your Dice With Bluetooth

December 10, 2017 by Sven Gregori 19 Comments

There’s no shortage of projects that replace your regular board game dice with an electronic version of them, bringing digital features into the real world. [Jean] however goes the other way around and brings the real world into the digital one with his Bluetooth equipped electronic dice.

These dice are built around a Simblee module that houses the Bluetooth LE stack and antenna along with an ARM Cortex-M0 on a single chip. Adding an accelerometer for side detection and a bunch of LEDs to indicate the detected side, [Jean] put it all on a flex PCB wrapped around the battery, and into a 3D printed case that is just slightly bigger than your standard die.

While they’ll work as simple LED lighted replacement for your regular dice as-is, their biggest value is obviously the added Bluetooth functionality. In his project introduction video placed after the break, [Jean] shows a proof-of-concept game of Yahtzee displaying the thrown dice values on his mobile phone. Taking it further, he also demonstrates scenarios to map special purposes and custom behavior to selected dice and talks about his additional ideas for the future.

After seeing the inside of the die, it seems evident that getting a Bluetooth powered D20 will unfortunately remain a dream for another while — unless, of course, you take this giant one as inspiration for the dimensions.

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FrankenKorg: The Modern Remote Keyboard

December 9, 2017 by James Hobson 7 Comments

On a dreary night in November, [Smecher] collected the instruments of electronic life around him to infuse a musical spark into FrankenKorg — a resurrected keytar.

This hack is a “re-braining” of a RK-100 Korg Keytar, replacing the original circuits with an ATMega32 — the original functionality and appearance are preserved allowing any restored version of the original boards to be seamlessly re-integrated. In light of that, the original boards were ditched after a brief investigation, and a haphazard building process on a protoboard began. Three LS138 3-8 demuxers that accompany the ATMega handle scanning the keys since there weren’t enough pins on the ATMega alone for all the Korg’s features. Check out [Smecher]’s breakdown of his process in the video after the break!

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