El Cheapo Phased-Array Sonar

December 4, 2015 by 14 Comments

Sonar is a great sensor to add to any small-scale robot project. And for a couple bucks, the ubiquitous HC-SR04 modules make it easy to do. If you’ve ever used these simple sonar units, though, you’ve doubtless noticed that you get back one piece of information only — the range to the closest object that the speaker is pointing at. It doesn’t have to be that way. [Graham Chow] built a simple phased-array using two SR04 modules, and it looks like he’s getting decent results.

PB211200The hack starts out by pulling off the microcontroller and driving the board directly, a hack inspired by [Emil]’s work on reverse engineering the SR04s. Once [Graham] can control the sonar pings and read the results back, the fun begins.

[Graham] uses TI’s Cortex M4F LaunchPad eval kit to generate a ping and receive the reflections. With normal sonar, the time between the ping being sent and its reception is determined by the range to the target. In a phased array, in this case just the two modules, the difference in the times it takes for the ping to return to each module is used to determine the angle to the target.

phased_array_sonar_tableau

If you’re DSP-savvy, [Graham] is using a phase-shifted square wave signal so that the correlations of the sent and returned signals have better peaks. This also helps the peaks in correlation across the two SR04s in the array. We think it’s pretty awesome that [Graham] is resolving a couple of degrees in angular separation when he moved his wine bottle. With a couple more SR04 units, [Graham] could start to get height information back as well.

For not much scratch, [Graham] has himself an experimental setup that lets him play with some pretty heavy signal processing. We’re impressed, and can’t wait to see what’s next. Special thanks to [Graham] for posting up the code.

And thanks [João] for the tip!

3 Nerds + 2 Days = Little Big Pixel

December 3, 2015 by 2 Comments

Two days at a company sponsored hackathon? Sounds like fun to us! And productive too – the end result for [GuuzG] and two of his workmates from their company’s annual “w00tcamp” was this festive and versatile 16×16 pixel mega display.

From the sound of it, [GuuzG] and his mates at q42.com are not exactly hardware types, but they came up with a nice build nonetheless. Their design was based on 16 WS2812 LED strips for a 256 pixel display. An MDF frame was whipped up with cross-lap joints to form a square cell for each pixel. Painted white and topped with a frosted Plexiglass sheet, each RGB pixel has a soft, diffuse glow yet sharply defined borders. Powered by a pair of 5A DIN rail DC supplies and controlled by a Raspberry Pi, the finished display is very versatile – users can draw random pixel art, play the Game of Life, or just upload an image. [GuuzG] and company are planning to add Tetris, naturally, and maybe a webcam for fun.

We’ve seen lots of uses for the ubiquitous WS2812 LEDs, from clocks to Ambilight clones to ground-effect lighting for an electric skateboard. But if you’re in the mood for a display that doesn’t use LEDs, there’s always this multithreading display.

[via Reddit]

Don’t Be A Drone Noob This Christmas

December 3, 2015 by 23 Comments

Traditionally, getting into the hobby of flying model aircraft required spending some serious coin, not to mention hours and hours of building and learning. All of that leading up to a white-knuckled, hair raising maiden flight. If you were extremely lucky, you’d head home with only a slightly damaged plane – but many of us did a nice death spiral straight into the ground – all just so we could go home, and then start all over. Perhaps one of the reasons we’re seeing so many (negative) drone related news stories recently is that the price of admission to join the club of flying machines has never been so low. That, and there always seems to be one kid in the class that wants to ruin it for the rest of us.

This year the FAA expects about a million people to wake up Christmas morning with a drone under the tree.  And that’s a lot of chances for people to mess up. So if you’re planning on taking a drone up this year, you might want to watch the video after the break; Or just forward it to those that you think need to see it. If you’re into any sort of flying models you should already have [FliteTest] in your YouTube subscriptions – they have some really informative video, especially for the beginner wanting to get into the hobby.

This video guide is meant to be just a short introduction of what not to do. Obviously it doesn’t cover everything.  And we wouldn’t be looking out for our readers if we didn’t say that your local laws may vary – so do your homework, stay safe, and don’t be a drone noob.

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Windows 10 On A Tiny Board

December 3, 2015 by 105 Comments

Over the past few months, a number of companies and designers have started picking up the newest Intel SoCs. Intel has to kill ARM somehow, right? The latest of these single board x86 computers is the Lattepanda. It’s a tiny board that can run everything a 5-year-old desktop computer can run, including a full version of Windows 10.

This isn’t the first time we’ve seen a tiny x86 board in recent months. Last October, an x86 board that takes design cues from the Raspberry Pi 2 hit Kickstarter. These are proper PCs, with the ability to run Windows 10, Linux, and just about every other environment under the sun.

The specs for the Lattepanda include a quad-core Cherry Trail running at 1.8GHz. the RAM is either 2GB or 4GB depending on configuration, and 32GB of eMMC Flash. Peripherals include USB 3.0, Ethernet, WiFi, Bluetooth, and integrated graphics supporting either HDMI or a DSI connector.

But of course a computer is just a computer, and you can’t sell a machine that only runs Skype to the ‘maker’ market. The Lattepanda also includes an ATMega32u4 as a coprocessor, giving this board ‘Arduino functionality’. In my day we walked uphill both ways to get a parallel port, but I digress.

While these tiny x86 boards might not be available in a year’s time, and the companies behind them may fall off the face of the planet, the introduction of these devices portends a great war over the horizon. Intel wants the low-power SoC market, a space until now reserved entirely for ARM-based devices.

4 Port USB, Raspberry Pi Zero Piggy-Back Hack

December 3, 2015 by 54 Comments

[Frederick] decided his new Zero needed a USB hub. He noticed a small, on hand, USB hub was the same size as the Zero. As any good hacker would, he stripped it from its case to piggy-back it onto the Zero. What’s with the piggy-backing since we just saw that with another Zero hack that added a WiFi dongle? Is it something in the water? Nah, probably just a natural fit with the mini-sized Zero.

Foam and elastic bands make a next arrangement
Tricky wiring to the hub’s USB

It certainly helps that the USB and power pads on the back of the Zero are available and of a good size to accept direct, soldered wire connections. The USB connections on the hub were a little more tricky. The wires were soldered to the surface mount pins of the mini-B connector. But [Frederick] managed to get that done, also.

A nice advantage of this hack is that a couple of soldered jumper wires let the Zero draw power from the hub’s wall-wart, eliminating one cable from those needed to work with the Pi. Using hot glue for strain relief on the wiring is a nice touch. To keep the boards from shorting he put a piece of foam between them and help them together with elastic bands. Simple and easy.

Kay Igwe Explains Brain Gaming Through SSVEP

December 3, 2015 by 12 Comments

We had some incredible speakers at the Hackaday SuperConference. One of the final talks was given by [Kay Igwe], a graduate electrical engineering student at Columbia University. [Kay] has worked in nanotechnology as well as semiconductor manufacturing for Intel. These days, she’s spending her time playing games – but not with her hands.

Many of us love gaming, and probably spend way too much time on our computers, consoles, or phones playing games. But what about people who don’t have the use of their hands, such as ALS patients? Bringing gaming to the disabled is what prompted  [Kay] to work on Control iT, a brain interface for controlling games. Brain-computer interfaces invoke images of Electroencephalography (EEG) machines. Usually that means tons of electrodes, gel in your hair, and data which is buried in the noise.

[Kay Igwe] is exploring a very interesting phenomenon that uses flashing lights to elicit very specific, and easy to detect brain waves. This type of interface is very promising and is the topic of the talk she gave at this year’s Hackaday SuperConference. Check out the video of her presentation, then join us after the break as we dive into the details of her work.

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Retrocomputing On A Chip

December 3, 2015 by 10 Comments

New electrical components enable us to reconstruct old wiring more efficiently. Especially, the accessible and cheap FPGA kits which offer the possibility to put together wiring of many old computers as an “on-a-chip” solution.

When I managed to get a hold of an old bubble LED display and a pretty mechanical matrix keyboard, I decided to build a replica of an old single board computer. Logical options seemed to be to build either KIM-1 or Heathkit ET-3400. Replicas of KIM-1 already exist, even for Arduino, so my task would be reduced to connect the keyboard and display. But then I told myself that I would use the fact that my bubble display has 9 positions as an excuse to build the legendary Czechoslovak Single Board Computer PMI-80 which used the same display. My replica is an FPGA, or rather an FPGA emulator of this very computer.

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