A Virtual Touchscreen (3D Ultrasonic Radar)

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Producing items onto a screen simply by touching the air is a marvelous thing. One way to accomplish this involves four HC-SR04 ultrasonic sensor units that transmit data through an Arduino into a Linux computer. The end result is a virtual touchscreen that can be made at home.

The software of this device was developed by [Anatoly] who translated hand gestures into actionable commands. The sensors attached to the Arduino had an approximate scanning range of 3m, and the ultrasonic units were modified to broadcast an analog signal at 40 kHz. There were a few limitations with the original hardware design as [Anatoly] stated in the post. For example, at first, only one unit was transmitting at a time, so there was no way the Arduino could identify two objects on the same sphere. However, [Anatoly] updated the blog with a 2nd post showing that sensing multiple items at once could be done. Occasionally, the range would be finicky when dealing with small items like pens. But besides that, it seemed to work pretty well.

Additional technical specifications can be found on [Anatoly]‘s blog and videos of the system working can be seen after the break.

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Open Source Marker Recognition for Augmented Reality

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[Bharath] recently uploaded the source code for an OpenCV based pattern recognition platform that can be used for Augmented Reality, or even robots. It was built with C++ and utilized the OpenCV library to translate marker notations within a single frame.

The program started out by focusing in on one object at a time. This method was chosen to eliminate the creation of additional arrays that contained information of all of the blobs inside the image; which could cause some problems.

Although this implementation did not track marker information through multiple frames, it did provide a nice foundation for integrating pattern recognition into computer systems. The tutorial was straightforward and easy to ready. The entire program and source code can be found on Github which comes with a ZERO license so that anyone can use it. A video of the program comes up after the break:

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Hackaday Links: August 24, 2014

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Remember those ‘cocktail’ arcade cabinets? The Ikea Lack table has existed for years, so why not make one into an arcade table? Raspberry Pi with RetroPie as the brains,  and an ancient 4:3 monitor as the display.

Old Unixes! Running on PDPs, Novas, and IBMs! Thanks to Simh, you can emulate these old machines. [Matt] put up a guide to getting Simh running on a Pi that includes running Unix V5 on an emulated PDP-11.

Ever wanted to run your own telecom? The folks at Toorcamp did just that, 50 lines, 10,000 feet of 1-pair, and 1,500 feet of 2-pair. There’s a facebook album of all the pics.

Remember last week when Sparkfun said they shipped 2000 Microviews without a bootloader? Make interviewed [Marcus Schappi], the guy behind the MicroView. There’s also a tutorial on how to fix the issue.

Barbie needs an exorcism.

Remember the [Lord Vetinari] clock from way back when? It’s a clock that ticks 86400 times a day, but the interval between each second is just slightly random and enough to drive people insane. Here’s a kit on Tindie that makes it pretty easy to build a Ventinari clock, or a variety of other clocks that are sufficiently weird. There’s also a martian clock that’s 39 minutes and 36 seconds longer than normal, perfect for the folks at JPL.

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A Geiger Counter for an Off-Road Apocalypse Vehicle

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If the world comes to an end, it’s good to be prepared. And let’s say that the apocalypse is triggered by a series of nuclear explosions. If that is the case, then having a Geiger counter is a must, plus having a nice transport vehicle would be helpful too. So [Kristian] combined the two ideas and created his own Geiger counter for automotive use just on the off chance that he might need it one day.

It all started with a homemade counter that was fashioned together. Then a display module with a built-in graphics controller that was implemented to show all kinds of information in the vehicle. This was done using a couple of optocouplers as inputs. In addition, a CAN bus interface was put in place. As an earlier post suggests, the display circuit was based on a Microchip 18F4680 microcontroller. After that, things kind of got a little out of control and the counter evolved into more of a mobile communications center; mostly just because [Kristian] wanted to learn how those systems worked. Sounds like a fun learning experience! Later the CPU and gauge was redesigned to use low-quiescent regulators. A filtering board was also made that could kill transients and noise if needed.

The full project can be seen on [Kristian]‘s blog.

Phone Gyroscope Signals Can Eavesdrop on Your Conversations

A gyroscope is a device made for measuring orientation and can typically be found in modern smartphones or tablet PCs to enable rich user experience. A team from Stanford managed to recognize simple words from only analyzing gyroscope signals (PDF warning). The complex inner workings of MEMS based gyroscopes (which use the Coriolis effect) and Android software limitations only allowed the team to only sniff frequencies under 200Hz. This may therefore explain the average 12% word recognition rate that was achieved with custom recognition algorithms. It may however still be enough to make you reconsider installing an app that don’t necessarily need access to the on-board sensors to work. Interestingly, the paper also states that STMicroelectronics currently have a 80% market share for smartphone / Tablet PCs gyroscopes.

On the same topic, you may be interested to check out a gyroscope-based smartphone keylogging attack we featured a couple of years ago.

The Counter-Strike Airsoft Robot

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[Jon] and his brother converted an RC car into a robot that can fire airsoft pellets into the air. The little motorized vehicle was disassembled and a handheld was attached to the top. A pulling mechanism was put in place and a safety procedure was added to make sure no accidents occurred.

The chassis stand was created to hold the handle. The setup was then tested at this point, and a Raspberry Pi server was configured to have a camera that would act as the eyes for the robot. Once everything was in place, the wheels hit the ground and the vehicle was able to move around, positioning itself to aim the servos at a designated target. Footage was transmitted via the web showing what the robot was looking at.

A video of the remote-controlled counter-strike robot can be seen after the break. You could consider this your toy army. That makes this one your toy air force.

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FPGA with Open Source Propeller 1 Running Spin

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Open Sourcing something doesn’t actually acquire meaning until someone actually uses what has been unleashed in the wild. We’re happy to see a working example of Propeller 1 on an FPGA dev board. That link takes you to a short description and some remapping of the pins to work with a BeMicro CV board. But you’ll want to watch the video below, or rather listen to it, for a bit more explanation of what [Sylwester] did to get this working.

You’ll remember that Parallax released the Propeller 1 as Verilog code a few weeks back. This project first loads the code onto the FPGA, then proves it works by running SIDcog, the Commodore 64 sound emulation program written in Spin for p8x32a processors.

We do find this to be an interesting first step. But we’re still waiting to see what type of hacks are made possible because of the newly available Verilog code. If you have a proof of concept working on other hardware, certainly tell us about it below. If you’ve been hacking on it and have something you want to show off, what are you waiting for?

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