Bike Pedals In Both Directions, Gets You To Your Destination AND Back

April 5, 2014 by Rich Bremer 48 Comments

[punamenon2] has built an interesting bike that moves forward regardless if it is pedaled forward or backwards! What? Yes, you read that correctly. Pedal forward or backwards and the bike goes forward. This project started off as any old cruiser with a free-wheeling rear hub. To pull off this mod a second free-wheel and sprocket had to be added to the current wheel assembly. One free-wheel and sprocket set is used when pedaling forward, the other set is used when pedaling in reverse. There is also a new chain tensioner that serves to not only keep the chain taut but also allows for the chain to change directions which ultimately allows this novel idea to work.

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Taking Pictures With A DRAM Chip

April 5, 2014 by Eric Evenchick 65 Comments

This picture was taken by using a DRAM chip as an image sensor (translated). A decapped 64k DRAM chip was combined with optics that could focus an image onto the die. By reading data out of the DRAM, the image could be constructed.

DRAM is the type of RAM you find on the RAM cards inserted into your motherboard. It consists of a massive array of capacitors and transistors. Each bit requires one transistor and one capacitor, which is quite efficient. The downside is that the memory needs to be refreshed periodically to prevent the capacitors from discharging.

Exposing the capacitor to light causes it to discharge faster. Once it has discharged past a certain threshold, the bit will flip from one to zero. To take a picture, ones are written to every bit in the DRAM array. By timing how long it takes a bit to flip from one to zero, the amount of light exposure can be determined. Since the DRAM is laid out in an array, each bit can be treated as a pixel to reconstruct the image.

Sure, modern CCDs are better, cheaper, and faster, but this hack is a neat way to totally re-purpose a chip. There’s even Turbo Pascal source if you’d like to recreate the project.

Thanks to [svofski] for the tip.

Web Interface For The FRAM LaunchPad

April 5, 2014 by Nick Conn 10 Comments

webUILaunchpad The Internet of Things is here in full force. The first step when adding to the Internet of Things is obvious, adding a web interface to your project. [Jaspreet] wrote in to tell us about his project that adds a web interface to his MSP430 based project, making it easy to add any project to the internet of things.

Creating a web interface can be a bit overwhelming if you have never done it before. This project makes it easy by using a dedicated computer running Linux to handle all of the web related tasks. The LaunchPad simply interfaces with the computer using USB and Python, and the computer hosts the webpage and updates it in real time using Node.js. The result is a very professional looking interface with an impressively responsive display that can control the on-board LEDs, read analog values from the integrated ADC, and stream accelerometer data. Be sure to see it in action after the break!

We could see this project being expanded to run on the Raspberry Pi with a multitude of sensors. What will you add a web interface to next? Home automation? A weather station? Let us know!

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Robot Cage Fighting Is Still A Thing!

April 4, 2014 by James Hobson 25 Comments

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Remember Battlebots? Turns out it is alive and well in Southern California at the National Tooling and Machining Association (NTMA) Robotics League. That’s right — high school students are getting to build remote controlled weaponized robots to battle to the death inside a poly-carbonate octagon arena. Awesome.

[Bradley Hanstad] wrote to us today to inform us of the 2014 Regional Competition — happening tomorrow at 10AM (PDT). We can’t make it there ourselves, but there is a live stream for everyone to see!

The league started just this fall which currently consists of 15 area high schools, community colleges, and technical schools. The goal of the league is to spark an interest in engineering and manufacturing in young students, while at the same-time providing hands-on education on the applied side of the sciences. It’s sometimes tricky to get students engaged in engineering competitions — but as soon as you say fighting robots you will have most peoples’ attention.

To see a teaser trailer for what is to come at these competitions, stick around after the break!

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Powering A RPi With Hydrogen

April 4, 2014 by Eric Evenchick 23 Comments

Looking for a new way to power your Raspberry Pi? The raspberryHy project aims to develop a small fuel cell designed for powering the credit card sized computer. It adds a proton exchange membrane (PEM) fuel cell, a battery, and custom control electronics to the Pi.

The system takes hydrogen in from a compressed hydrogen cartridge and feeds it through a regulator. This passes the hydrogen into the PEM fuel cell at the correct pressure, and creates a potential. The control electronics boost that voltage up to the 5 V required on the Pi’s USB port. There’s also an electronically controlled purge valve which periodically exhausts the fuel cell.

There’s a few reasons you might want to run your Pi with hydrogen. Run time of the fuel cell is limited only by the amount of hydrogen you can store. In theory, you could connect a large cylinder for very long run times. Combined with a battery, this could be quite useful for running Pis in remote locations, or for long-term backup power. The raspberryHy will be presented at Hannover Fair 2014 this month.

Building An Inductive Loop Vehicle Detector

April 4, 2014 by Mathieu Stephan 26 Comments

[Trax] was asked by a friend to build a device that could detect the presence of a car in front of his garage gate for it to open automatically. After searching the web for such a project and trying many of them, he decided to build his own detector based on an induction loop. As you may have guessed, this kind of detector works by detecting an inductance change in a wire loop (aka coil) buried in the road. Having a car pass several inches on top of it produces such an effect.

[Trax]’s write-up shows a very well thought and professional design. All the detector parameters can be adjusted using DIP switches and buttons: detection type (presence/pulse), signal filtering, main frequency and sensitivity. The wire loop is isolated from the main sensor electronics using a 1:1 isolation transformer and a Colpitts oscillator is used to drive the latter. Moreover, gas discharge tubes are also used for lightning protection.

The change in inductance translates to a change in resonant frequency which is later detected by the main microcontroller. The board is 24V AC powered and a diode bridge + LM2596 SMPS step-down converter are in charge of generating the required +5V in an efficient way.

As if this was not enough, [Trax] also made a PC-based tool that can change other platform settings using a serial connection. All the resources can be downloaded from his website and a few videos are embedded after the break.

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Sci-Fi Contest: Source Universe Roundup

April 4, 2014 by Mike Szczys 8 Comments

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The Hackaday Sci-Fi contest has 36 entries so far. Since there are fifteen prizes available, you stand an excellent chance of winning; but you can’t win if you don’t play. It’s pretty easy to be considered for the contest. You simply need to hack together something Sci-Fi related and show off your work. Head over to the contest page and check out the details. Ten of the prizes are popularity-based, so posting early is the best bet! For those that were put-off by the team requirement, there’s a hack to get around that.

Since this is a themed contest we thought we’d give you an update on where inspiration is coming from. Below is the break-down of each Sci-Fi universe that has been so-far adopted by the entrants. We’d like to point out that this isn’t limited to movies, as the bulk of inspiration is to be found in literature. Why don’t we get a comment thread going here to help brain-storm for people who want help locking onto an idea?

Oh, and if you’re wondering about the banner images. These were taken from three of the contest projects. The upper left is a GLaDOS replica controlled by Google Glass (complete with Nerf dart gun) inspired by Portal. Bottom left is a pair of Peril-Sensitive sunglasses inspired by A Hitchhiker’s Guide to the Galaxy. And the bottom right is a life-sign scanner inpired by Stargate Atlantis.