Friction Welding… Wood?

November 8, 2015 by 62 Comments

You’d think writing for Hackaday means we probably don’t get surprised very often by projects… but then we see something we never thought was possible — in this case, the linear friction welding of wood to join it.

Friction welding (also known as stir welding), is the process of taking two pieces of material (typically metal, or plastic), and vibrating one of them super fast while pushing against a stationary piece of the same material — the resulting friction causes a massive heat buildup that can then literally weld the two pieces of material together.

It’s an easy way to bond plastic parts together using a dremel and some 3D printing filament, and while doing it with metal is significantly harder, it is possible to do at home as well.

But according to the video after the break — it’s actually possible to do this with wood.

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Casting Turbines For A World Speed Record Motorcycle

November 8, 2015 by 24 Comments

[Anders] is going to beat the land speed record for a turbine-powered motorcycle. It’s a project he’s been working on for years now, and just this week, he put the finishing touches on the latest part of the build. He successfully cast the compressor for a gas turbine engine that’s twice as powerful as the one he has now.

This compressor piece was first 3D printed, and this print was used as a positive for a sand – or more specifically petrobond – mold. The material used in the casting is aluminum, fluxed and degassed, and with a relatively simple process, [Anders] came away with a very nice looking cast that only needs a little bit of milling, lathing, and welding to complete the part.

In the interests of accuracy, and just to make sure there’s no confusion, this ‘jet’ engine is actually a gas turbine, of which there are many configurations and uses. The proper nomenclature for this engine is a ‘turboshaft’ because the power is directed to a shaft which drives something else. This is not a new build; we’ve been covering [Anders]’ build for the better part of two years now, and although [Anders] intends to break the world record at the Bonneville salt flats eventually, he won’t be beating the ultimate land speed record – that title goes to a car – and he won’t be beating the speed record for all motorcycles. Instead, [Anders] plans to break the record for experimental propulsion motorcycles, or motorcycles powered by electric motors, steam, jet engines, or in this case, ‘turboshafts’.

It should also be noted that [Anders] frequently does not wear hearing or eye protection when testing his gas turbine engine. That is an exceedingly bad idea, and something that should not be attempted by anyone.

As an additional note for safety, in the video below of [Anders] pouring aluminum into his mold, the ground looks wet. This is terrifically dangerous, and steam explosions can kill and maim even innocent bystanders. This is not something that should be attempted by anyone, but we do thank [Anders] for sharing his project with us.

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Weather Word Clock Warns You Of Impending Winter

November 8, 2015 by 3 Comments

Word clocks are pretty popular “artsy” ways of telling time, but [doktorinjh] wanted to try something a little different. So instead of showing the time — it shows the weather.

He’s using an Arduino Yun to access the Weather Underground API for data and then sends the data out to a grid of 100 individually addressable RGB LEDs — NeoPixels to be precise. The LEDs are overlayed with a laser cut acrylic sheet with various words and weather icons to allow for a pretty specific depiction of current (or future) weather conditions.

The frame is made out of colonial style molding and since it’s a weather clock, he turned the grid of LEDs into a rainbow effect, because, why not?

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Compressorhead: Best Robot Band Ever?

November 7, 2015 by 12 Comments

We’ve written about Compressorhead before but we’re writing about them again. Why? Because Compressorhead is the most amazing robot band you’ve ever seen, and because they’ve just opened up a Kickstarter to fund building a lead singer robot and recording an album.

And because they’ve released a bunch of new videos, one of which you’ll find below the break.

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Measuring Tire Pressure By Cutting A Hole In An Inner Tube

November 7, 2015 by 56 Comments

RFID tags are really very primitive pieces of technology. Yes, they harvest energy from an RFID reader and are able to communicate a few bits of data, but for a long time these tags have been unable to provide useful data beyond a simple ID number. [CaptMcAllister] found a new RFID sensor platform from TI and managed to make a wireless pressure sensor that fits in the inner tube of his bike.

The sensor [Capt] is using comes from TI’s RF430 series that include a few neat sensors that don’t require batteries, but are still able to communicate sensor data to a cell phone or other RFID reader. With a pressure sensor, this tiny microcontroller can receive power from an RFID reader and send it back to a phone app, all without wires.

[CaptMcAllister] cut open an inner tube for his bike, epoxied his PCB to a patch, and sealed everything back up again. After a quick test for leaks, [Capt] found the data coming from the sensor was extraordinarily accurate, and should hold up well enough to be used in his bike.

Air Quality Surveillance For Whole Cities

November 7, 2015 by 12 Comments

Air quality is becoming a major issue these days, and not just for cities like Beijing and Los Angeles. It’s important for health, our environment, and our economy no matter where we live. To that end, [Radu] has been working on air quality monitors that will be widely deployed in order to give a high-resolution air quality picture, and he’s starting in his home city of Timisoara, Romania.

[Radu] built a similar device to measure background radiation (a 2014 Hackaday Prize Semifinalist), and another to measure air quality in several ways (a 2015 Hackaday Prize Finalist and a Best Product Finalist; winners will be announced next weekend). He is using the platforms as models for his new meter. The device will use a VOC air sensor and an optical dust sensor in a mobile unit connected to a car to gather data, and from that a heat map of air quality will be generated. There are also sensors for temperature, pressure, humidity, and background radiation. The backbone of the project is a smart phone which will upload the data to a server.

We’ve seen other air quality meters before as well, and even ones based around the Raspberry Pi,  but this one has a much broader range of data that it is acquiring. Its ability to be implemented as an array of sensors to gather data for an entire city is impressive as well. We can envision sensor networks installed on public transportation but to get to all parts of every neighborhood it would be interesting to team up with the Google Streetview Cars, Uber, or UPS.

Low Power And Pin-Constrained

November 7, 2015 by 30 Comments

We’ve all been there. You’re building up a microcontroller project and you wish that you could just add “one more feature” but you’re limited by the hardware. Time to start thinking. (Or, arguably, buy the next model up.)

[Sam Feller] found himself in this position, adding a knob to set the time and a button to arm the alarm for his Analog Voltmeter Clock, and he came up with a way to implement an on-off switch, and poll a button and a potentiometer with only two pins of a microcontroller.

The problem with potentiometers in low-power designs is that they’re always leaking power. That is, unless you switch them off when you’re not using them. So the ideal solution is to power the potentiometer from one GPIO pin on the microcontroller, and read its value with another. That’s two GPIO pins just for the potentiometer. But [Sam] needed to read input from a button too, and he was out of pins.

Not pressed: pot sees VCC and VCC/2
Pressed: pot sees VCC/2 and GND

His clever solution is to switch two resistors in or out of the circuit depending on the status of the pushbutton, so that the voltage range at the potentiometer is between either VCC and VCC/2 when the switch is pressed, or between VCC/2 and GND when the switch is not pressed.

If the ADC reads something higher than VCC/2, the microcontroller knows that the button is pressed, and vice-versa. The potentiometer’s setting determines exactly where the voltage lies within either range.

Done and done. If you find yourself in the similar situation of needing to read in values from a whole bunch of buttons instead of a potentiometer, then you can try using an R-2R DAC wired up to the pushbuttons and reading the (analog) value to figure out which buttons are pressed. (If you squint your eyes just right, this solution is the same as the R-2R DAC one with the potentiometer replacing all but the most-significant bit of the R-2R DAC.)

Another tool for the toolbox. Thanks [Sam].