Flying Planes With Squirrel Cages

Fixed wing remote control planes are ridiculously overpowered. Whereas normal, manned fixed wing aircraft need to take into account things like density altitude, angle of attack, and weight limits, most RC aircraft can hover. This insane amount of power means there’s a lot of room for experimentation, especially in new and novel power plants. [Samm Sheperd] had an old squirrel cage fan taken from an electric wall heater and figured one man’s trash was an integral part of another man’s hobby and built a plane around this very unusual fan.

squirrel-cage-fan-wideThe only part of the squirrel cage fan [Samm] reused was the impeller. Every other part of this power plant was either constructed out of foam board, plywood, or in the case of the brushless motor turning the fan, stolen from the ubiquitous box of junk on every modeller’s workbench.

The design of the plane puts the blower fan directly under the wings, blasting the air backwards underneath the empennage. During testing, [Samm] found this blower pulled around 350W from the battery – exactly what it should draw if a properly sized propeller were attached to the motor. The thrust produced isn’t that great — only about 400g of thrust from an airframe that weights 863g. That’s very underpowered for an RC aircraft, but absurdly powerful for any manned flying machine.

Does the plane work? Of course it does. [Samm] took his plane for a few laps around the neighborhood and found the plane flies excellently. It is horrifically loud, but it is a great example of how much anyone can do with cheap RC planes constructed out of foam.

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32C3: A Free And Open Source Verilog-to-Bitstream Flow For ICE40 FPGAs

[Clifford] presented a fully open-source toolchain for programming FPGAs. If you don’t think that this is an impressive piece of work, you don’t really understand FPGAs.

The toolchain, or “flow” as the FPGA kids like to call it, consists of three parts: Project IceStorm, a low-level tool that can build the bitstreams that flip individual bits inside the FPGA, Arachne-pnr, a place-and-route tool that turns a symbolic netlist into the physical stuff that IceStorm needs, and Yosys which synthesizes Verilog code into the netlists needed by Arachne. [Clifford] developed both IceStorm and Yosys, so he knows what he’s talking about.

What’s most impressive is that FPGAs aren’t the only target for this flow. Because it’s all open source and modifiable, it has also been used for designing custom ASICs, good to know when you’re in need of your own custom silicon. [Clifford]’s main focus in Yosys is on formal verification — making sure that the FPGA will behave as intended in the Verilog code. A fully open-source toolchain makes working on this task possible.

If you’ve been following along with [Al Williams]’s FPGA posts, either this introduction or his more recent intermediate series that are also based on the relatively cheap Lattice iCEStick development kit, this video is a must-watch. It’s a fantastic introduction to the cutting-edge in free FPGA tools.

Desoldering Doesn’t Necessarily Suck

What’s your favorite way to fix soldering mistakes or get usable components off that board you found in a Dumpster? I’ve always been partial to desoldering braid, though I’ve started to come around on the vacuum pump depending on the situation. [Proto G] sent in an Instructable that outlines nine different ways to desolder components that take varying amounts of time and skill.

He starts with one that is often overlooked if you don’t have a solder pot. [Proto G] recommends this method only when you don’t want to keep the board. Cover the solder joints of the components you want to keep with flux and hold it over the solder pot while pulling out the components with pliers. The flux isn’t critical, but it makes removal faster and easier.

For boards in need of repair, [Proto G] uses a manual pump or copper desoldering braid that comes coated with flux. If you can afford one, a desoldering machine seems like the way to go—it combines the heat of a soldering iron with the vacuum of a manual pump. Desoldering tweezers and hot air rework stations look like great ways to remove surface mount components.

If you enjoyed this, check out [Bil Herd’s] guide on component desoldering. There are also few ways that [Proto G] doesn’t mention, like holding the board over an alcohol flame. Let us know your favorite desoldering method in the comments.

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Mobile Mini Green Recreates Coeur D’Alene’s Floating 14th Hole

Golf is an expensive obsession for some, with course fees on the most memorable and challenging courses running into the hundreds of dollars a game and beyond. If playing one of the most unusual holes in golf is simply beyond your means, there’s no need to fret – just do what [TVMiller] did and build a miniature mobile replica of the famous Coeur d’Alene Resort Floating 14th hole.

The Floating 14th is pretty spectacular as far as golf holes go. With a green located on an island about a hundred yards offshore of beautiful Lake Coeur d’Alene in northern Idaho, there’s little room for error – after all, it’s surrounded by a 49 square mile water trap. [TVMiller]’s replica green recreates the target quite accurately, although we doubt the Jolly Wrencher flag is regulation for championship play. But the best part is the motorized platform and smartphone app that can be used to send the mini green out as far as you feel like practicing. Sure, it could be a tad more realistic if the replica green actually floated, but asphalt fairways are a little easier to come by than Olympic-sized swimming pools.

A fun, tongue-in-cheek project, and we really enjoyed the faux TV coverage of the 2015 Hackaday Golf Championship in the video below. If real golf isn’t your thing, you might want to build a table-top golf course, or play a round of mini golf with a ball-incinerating Portal themed hole.

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The Effects Of Color On Material Properties Of 3D Printed Components

The strength of object printed on filament-based 3D printers varies by the plastic used, the G-code used by the printer, the percent infill, and even the temperature the plastic was extruded at. Everything, it seems, has an effect on the strength of 3D printed parts, but does the color of filament have an effect on the stress and strain a plastic part it can withstand? [Joshua M. Pearce] set out to answer that question in one of his most recent papers.

The methods section of the paper is about what you would expect for someone investigating the strength of parts printed on a RepRap. A Lulzbot TAZ 4 was used, along with natural, white, black, silver, and blue 3mm PLA filament. All parts were printed at 190°C with a 60°C heated bed.

The printed parts demonstrated yet again that a RepRap can produce parts that are at least equal in material strength to those produced by a proprietary 3D printer. But what about a difference in the strength among different colors? While there wasn’t a significant variation in the Young’s modulus of parts printed in different colors, there was a significant variation of the crystallization of differently colored printed parts, with white PLA producing the largest percent crystallinity, followed by blue, grey, black, and finally natural PLA. This crystallinity of a printed part can affect the tensile properties of a printed part, but [Pearce] found the extrusion temperature also has a large effect on the percentage of crystallinity.

Color Sonification Could Be Key To Rainbow Connection

Have you seen any loud sweaters this holiday season? Now there is a way to quantify their vibrancy and actually hear them at the same time. Cornell engineering students [Mengcheng Qi] and [Ryan Land] focused on the sonification of color and translated the visible spectrum into audible sounds.

They originally planned to use pixel samples from an OV7670 camera module, but weren’t able to extract any useful color data from it. We prefer their Plan B anyway, which was to use CdS photo resistors and the plastic color filters used for photography in red, blue, and green. The varying intensity of light falling on the photo resistors creates different patterns according to the voltage levels. The actual sound generation was done with FM sound synthesis.

There wasn’t a lot of natural sound variation between different RGB values, so in order to make it more fun, they created different instruments which play different patterns at variable speeds and pitch according to the colors. In addition to the audio feedback, the RGB values are displayed in real-time on a small TFT. Below those are dynamic bar graphs that show the voltages of each color.

Check out the demo after the break; they walk through the project and try it out on different things to hear their colors.

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Parts Bin Emergency Lights Deal With Tornado’s Aftermath

Sometimes having a deep inventory of parts in your shop is a pain – the clutter, the dust, the things you can’t rationally justify keeping but still can’t bear to part with. But sometimes the parts bin delivers and lets you cobble together some emergency lighting when a tornado knocks out your power.

It has been hard to avoid discussions of the weird weather in the US this winter. The eastern half of the country has had record warm temperatures, the west has been lashed by storms, and now December tornadoes have ripped through Texas and other parts of the south, with terrible loss of life and wide-ranging property damage. [TheTimmy] was close enough to one massive EF4 tornado to lose power on Saturday night, and after the charm of a candlelight Christmas evening wore off, he headed to the shop. He had a bunch of sealed lead acid batteries from old UPSs and a tangle of 12V LED modules, and with the help of some elastic bands and jumper clips he wired up a bunch of lights for around the house. Safer than candles by a long shot, and more omnidirectional than flashlights to boot.

The power came back before the batteries ran out of juice, so we don’t get to see any hacks for recharging batteries in a grid-down scenario. Still, it’s good to see how a deep parts bin and good mindset can make a positive impact on an uncomfortable situation. We’ve seen similar hacks before, like this hacked cordless tool battery pack or powering a TV with 18650 batteries. Be sure to share your story of epic power-outage hacks in the comments below.